Re: Using python for writing models: How to run models in restricted python mode?
vinjvinj [EMAIL PROTECTED] writes: 1. restrict the user from doing any file io, exec, import, eval, etc. I was thinking of writing a plugin for pylint to do all the checks? Is this is a good way given that there is no restricted python. What are the things I should serach for in python code Um - I've got a restricted python module: rexec.py. Of course, it doesn't work correctly, in that it isn't really secure. Python is very powerful, and creating a secure sandbox is difficult - so much so that the task has never been accomplished. If you want something that will keep the obvious things from working, rexec.py might be for you - but don't kid yourself that it's secure. If you need real security, I'd consider switching to Jython, which at least has a VM which was designed with building such sandboxes as a possibility. 2. restrict the amount of memory a module uses as well. For instance how can I restrict a user from doing a = range(100) or similar tasks so that my whole compute farm does not come down. This is equivalent to trying to limit the amount of CPU time the module uses, which is better known as the halting problem. There's no algorithmic solution to that. If you want verify that some module will only use so much memory before executing it, the best you can do is verify that they don't do anything obvious. If you want to restrict them while they are running, you can probably get the OS to help. Exactly how will depend on your requirements, and the OS involved. Mike -- Mike Meyer [EMAIL PROTECTED] http://www.mired.org/home/mwm/ Independent WWW/Perforce/FreeBSD/Unix consultant, email for more information. -- http://mail.python.org/mailman/listinfo/python-list
Re: Web automation
[EMAIL PROTECTED] writes: but I supposed the everyone knew that web automation (and in general automation) is only a problem in Linux. I don't know it. I don't believe it, either. I automate web tasks on Unix systems (I don't use many Linux systems, but it's the same tool set) on a regular basis. In fact, I automate *lots* of tasks on Unix systems on a regular basis, and have been doing it for decades. Most Unix tools are very amenable to automation, much more so than I've found either Windows or OS X tools to be. mike -- Mike Meyer [EMAIL PROTECTED] http://www.mired.org/home/mwm/ Independent WWW/Perforce/FreeBSD/Unix consultant, email for more information. -- http://mail.python.org/mailman/listinfo/python-list
Re: Using python for writing models: How to run models in restricted python mode?
vinjvinj [EMAIL PROTECTED] writes: While I understand 2 is very hard (if not impossible) to do in single unix process. I'm not sure why 1 would be hard to do. Since I have complete control to what code I can allow or not allow on my grid. Can i not just search for certain strings and disallow the model if it fails certain conditions. It might not be 100% secure but will it not get me at 90%... Sure you can search for certain strings. Python lets you build strings dynamically, so you'd have to search for every possible way to create those strings. Further, Python provides lots of tools for introspection, meaning there are lots of ways to find these forbidden objects other than mentioning their name. You can get to *every* builtin function through any python module. For instance, are you going to prevent them from using regular rexpressions? If not, consider: getattr(re, ''.join([chr(x + 1) for x in [94, 94, 97, 116, 104, 107, 115, 104, 109, 114, 94, 94]]))['fi' + 'le'] is open True String searches only prevent the most obvious abuses, and may well miss things that are merely not quite so obvious. If you think of your security as a notice to the end user that they are doing something wrong, as opposed to a tool that will prevent them from doing it, then you'll have the right idea. In which case, I'd still recommend looking into the rexec module. mike -- Mike Meyer [EMAIL PROTECTED] http://www.mired.org/home/mwm/ Independent WWW/Perforce/FreeBSD/Unix consultant, email for more information. -- http://mail.python.org/mailman/listinfo/python-list
Re: Application monitor
dcrespo [EMAIL PROTECTED] writes: Main application starts This one starts the App Monitor of itself. (This means that if Main Application closes, the App Monitor restart it) And viceversa means that if App Monitor closes, the Main application restart it. How can I accomplish this? I've been thinking in wx.SingleInstanceChecker (from wxPython GUI library). If it doesn't exist, then call os.system(program_name). But I don't know if there's a better way. Better depends on what your requirements are. Personally, I use init as an app monitor. It doesn't need monitoring - if it's dead, your Unix has a lot worse problems than one application being down. mike -- Mike Meyer [EMAIL PROTECTED] http://www.mired.org/home/mwm/ Independent WWW/Perforce/FreeBSD/Unix consultant, email for more information. -- http://mail.python.org/mailman/listinfo/python-list
Re: Map of email origins to Python list
Claire McLister [EMAIL PROTECTED] writes: Thanks, Alan. You are absolutely right, we are not using the NNTP-Posting-Host header for obtaining the IP address. Yes, but what are you using? The Python list is unique among the lists that we have handled so far, in that it has a cross-posting mechanism with a net news. Hence, it seems we are getting many more wrong locations here than any other email list maps we've done so far. We've done them for Linux kernel, postresql, apache, tomcat, etc. You can find them by searching their names in the 'find' box. Not many people reported wrong locations on those maps. Hmm. Are you using a different method than you used for the mail lists? Because my mail and news follows the same path, using the same host name. The only difference is that my ISP uses supernews.com news servers, so my postings appear to go direct from my domain to supernews - but the only place this shows up is in the Path: header. For the record - I (and my servers) are in Virginia, the domain name I use is registered to an address in Oklahoma, and everything is relayed through my ISP in Berkeley. Your map has me in San Francisco. Ok, you nearly got my ISPs hardware. So, we'll have to go back and fix the script that is extracting the IP address (which is written in Python, btw). Let me know if someone is interested in taking a look at it and I can post it somewhere. What IP address it is extracting? Well, if you post it, I'll look at it and figure it out from that. mike -- Mike Meyer [EMAIL PROTECTED] http://www.mired.org/home/mwm/ Independent WWW/Perforce/FreeBSD/Unix consultant, email for more information. -- http://mail.python.org/mailman/listinfo/python-list
Re: [OT] Map of email origins to Python list
Claire McLister [EMAIL PROTECTED] writes: An interesting perspective. Not to increase your sense of 'creepy', but a lot of big corporations now have access to this kind of information and more. You mean my creditors are going to be looking for me in San Francisco, even though I'm in Virginia? Cool. mike -- Mike Meyer [EMAIL PROTECTED] http://www.mired.org/home/mwm/ Independent WWW/Perforce/FreeBSD/Unix consultant, email for more information. -- http://mail.python.org/mailman/listinfo/python-list
Re: how to modify code while debugging it without having to stop and then restart debugger
python [EMAIL PROTECTED] writes: i am a long time windows user and have had a great way to learn new api. There's a better way. See below. to write some code and then run it. if there is an error, the debugger will load. then i can figure out what the eror is, just touch up the ocde and continue to run the code. i do not have to stop the code, modify the code, rerun the code. often an error will only happen after a complex set of conditions and not have to completely stop the app is a fantastic way to debug. Yup. It's been around for decades. The cooler implementations will interpose a stage that offers you a set of proposed fixes as well as the ability to get to the debugger. so how can i use python to debug code and change that code without having to restart the code. Well, as James mentioned, you can use reload to reload your modules. But in general, this kind of thing doesn't work very well in OO languages in general, and in Python in particular. Here's an example of why: def f(): ... print Version 1 ... fp = f: def f(): ... print Version 2 ... f() Version 2 fp() Version 1 I changed the function f on the fly - just like you want to - but all the existing references to it will still refer to the *old* version of the function(*). To do the right thing, you need to fix all the references to the old code to refer to the new code as well. Unless your language has some ability to capture a code reference - first class functions, closures, or objects - that won't be a problem. But Python ha all those things, and every one of them causes problems like this. So you really can't continue your program from the debugger; you need to restart it to get everything that references code to reference the edited code. But if the point is to learn an API, then there's something a lot better than tweaking code inside a debugger. That's testing code inside the interpreter. When writing web scraping software with BeautifulSoup, writing the first guess at the scrape sequence and then tweaking it in the debugger would be ok. But being able to get the soup object in the interpreter, and try scrape sequences to see what they return directly is even better. Doing it in an Emacs buffer means I have a complete log of what I did to create the scrape, so I can reconstruct even complicated sequences if the need arises. If you hang out in this group long enough, you'll hear a lot about unit testing. It's an excellent idea, and I recommend it highly. However, it's always struck me as a very batch oriented approach. A more interactive approach is exploratory proramming, which is closer to what you're describing, and is appropriate when you don't know the problem space very well, or if - as when learning a new api - you don't know the tool set very well. Python is an excellent tool for this. It's not exactly like what you described, but different isn't necessarily inferior. mike *) This is a feature. Classic use is: oldfoo = foo def foo(*args, *kwds): # preprocess the arguments return oldfoo(*args, *kwds) -- Mike Meyer [EMAIL PROTECTED] http://www.mired.org/home/mwm/ Independent WWW/Perforce/FreeBSD/Unix consultant, email for more information. -- http://mail.python.org/mailman/listinfo/python-list
Re: Web automation
Paul Boddie [EMAIL PROTECTED] writes: Mike Meyer wrote: [EMAIL PROTECTED] writes: but I supposed the everyone knew that web automation (and in general automation) is only a problem in Linux. I don't know it. I don't believe it, either. I automate web tasks on Unix systems (I don't use many Linux systems, but it's the same tool set) on a regular basis. I imagine that Web automation is taken here to mean the automation of Web browsers Yeah, I know. It still seems like an ass-backwards approach to me. It's not at all clear that emulating user actions makes a sane model for scripting. I know the non-Unix systems I've seen that did things like that were clumsy compared to scripting interfaces that were designed from the ground up to be scripting interfaces. But that kind of thing varies from application to application on the systems that support scripting. The problem on non-Windows systems is the lack of a common (or enforced) technology for exposing application object models OS X has AppleScript. VM/CMS has Rexx. The Amiga had ARexx when MS was still peddling DOS. Plan 9 has files. I don't think any of them are enforced - then again, I don't think anything enforces exporting objects from Windows applications, either. The thing that sets all these apart from Unix is that the technology to export objects from applications came bundled as a core part of the OS. Unix still doesn't have that; instead it has a collection of languages that can be embedded in the application. Lots of applications do that, meaning they are automatable - but maybe not in the language you want to use for the project. Classic Unix (meaning pre-X) was automatable because programs were expected to produce output that could be processed by other programs. Those tools are still around and in daily use, and make task automation on Unix a common and easy thing. It's only when you restrict the meaning of automation to be driving a GUI app that you run into problems. mike -- Mike Meyer [EMAIL PROTECTED] http://www.mired.org/home/mwm/ Independent WWW/Perforce/FreeBSD/Unix consultant, email for more information. -- http://mail.python.org/mailman/listinfo/python-list
Re: problem generating rows in table
[EMAIL PROTECTED] writes:
hi
i wish to generate a table using cgi
toprint = [('nickname', 'justme', 'someplace')]
print '''table border=1
tr
tdUser/td
tdName/td
tdAddress/td
/tr
tr
'''
for i in range(0,len(toprint)-1):
for j in range(0,len(toprint[0])-1):
print td %s /td % toprint[i][j]
print '''/tr
/table'''
but it only prints out a table with User | Name | address
it didn't print out the values of toprint
is there mistake in code? please advise
You're not calling range right. It's designed for dealing with lists,
so range(n) returns [0, ..., n - 1], and range(to, bottom) returns
[top, ..., bottom - 1]. len(toprint) is 1, so len(toprint) - 1 is 0,
so you're calling range(0, 0), which is an empty list. So you make no
passes through the outer loop. Those two calls to range should be
range(len(toprint)) and range(len(toprint[i])) (n.b.: i, not 0, is
the index).
Of course, for is for walking elements of a list. You don't need the
indices at all. The pythonic way to write this loop would be:
for tup in toprint:
for el in tup:
print td %s /td % el
But your HTML is also broken. The loop as you have it will print one
row containing all the elements in toprint concatenated together. You
need to put each tuple in toprint into a separate row, like so:
for tup in toprint:
print tr
for el in tup:
print td %s /td % el
print /tr
print /table
and of course leave out the trailing tr in the print statement that
precedes the loop.
mike
--
Mike Meyer [EMAIL PROTECTED] http://www.mired.org/home/mwm/
Independent WWW/Perforce/FreeBSD/Unix consultant, email for more information.
--
http://mail.python.org/mailman/listinfo/python-list
Re: Using Which Version of Linux
Terry Hancock [EMAIL PROTECTED] writes: Similarly, I see RPMs by ones and twos all over the place, and only a few places with DEBs. But the DEB repositories are HUGE. Try rpmfind.net. It's not clear where the rpms reside, but it's not really important - it's a huge collection of RPMs. mike -- Mike Meyer [EMAIL PROTECTED] http://www.mired.org/home/mwm/ Independent WWW/Perforce/FreeBSD/Unix consultant, email for more information. -- http://mail.python.org/mailman/listinfo/python-list
Re: re sub help
[EMAIL PROTECTED] writes: i am still interested about using re, i find it useful. am still learning it's uses. so i did something like this for a start, trying to get everything in between [startdelim] and [enddelim] a = this\nis\na\nsentence[startdelim]this\nis\nanother[enddelim]this\nis\n t = re.compile(r\[startdelim\](.*)\[enddelim\]) t.findall(a) but it gives me []. it's the \n that prevents the results. why can't (.*) work in this case? Or am i missing some steps to read in the \n..? thanks. Newlines are magic to regular expressions. You use the flags in re to change that. In this case, you want . to match them, so you use the DOTALL flag: a = this\nis\na\nsentence[startdelim]this\nis\nanother[enddelim]this\nis\n t = re.compile(r\[startdelim\](.*)\[enddelim\], re.DOTALL) t.findall(a) ['this\nis\nanother'] mike -- Mike Meyer [EMAIL PROTECTED] http://www.mired.org/home/mwm/ Independent WWW/Perforce/FreeBSD/Unix consultant, email for more information. -- http://mail.python.org/mailman/listinfo/python-list
Re: Using Which Version of Linux
blahman ([EMAIL PROTECTED]) writes: ok, i m going to use Linux for my Python Programs, mainly because i need to see what will these fork() and exec() do. So, can anyone tell me which flavour of linux i should use, some say that Debian is more programmer friendly, or shold i use fedora, or Solaris. Because these three are the only ones i know of that are popular and free. You seem a bit confused. Solaris isn't a Linux distribution, it's (System V) Unix. Linux isn't Unix - it's a Unix look-like. *BSD is Unix, but they can't call it that for licensing reasons. Programmer-friendly is pretty vague. Gentoo is the only Linux distro I've run into (which excludes a *lot* of Unix distros) that I'd consider programmer friendly, because it doesn't split packages up into user stuff and developer stuff. That means you have to install two packages instead of one if you want to build things against that software. On the other hand, it uses it's own package manager - emerge - so you can't take advantage of rpms/debs from other systems (or you couldn't last time I looked into it). It also installs the least amount of bundled software, which I consider a programmer friendly behavior. Personally, I run FreeBSD - and I like gentoo because it has a lot in common with a BSD distribution. FreeBSD is the most popular of the BSDs. BSDs differ from Linuxen in that a BSD distribution is an integrated whole - the kernel and userland are maintained by the same group, in the same repository. So the number of BSD kernels to choose from is much greater than the number of Linux kernels, but the number of BSD distributions is much fewer. mike -- Mike Meyer [EMAIL PROTECTED] http://www.mired.org/home/mwm/ Independent WWW/Perforce/FreeBSD/Unix consultant, email for more information. -- http://mail.python.org/mailman/listinfo/python-list
Re: Using Which Version of Linux
Grant Edwards [EMAIL PROTECTED] writes: On 2005-11-05, Mike Meyer [EMAIL PROTECTED] wrote: Programmer-friendly is pretty vague. Gentoo is the only Linux distro I've run into (which excludes a *lot* of Unix distros) that I'd consider programmer friendly, because it doesn't split packages up into user stuff and developer stuff. That means you have to install two packages instead of one if you want to build things against that software. On the other hand, it uses it's own package manager - emerge - so you can't take advantage of rpms/debs from other systems (or you couldn't last time I looked into it). It also installs the least amount of bundled software, which I consider a programmer friendly behavior. I just switched one of my computers to gentoo, and I like it a lot. It's very no-nonsense, but there are alot of available packages and everything (so far) just works. However, it's not for the impatient (or at least not for the poor and impatient). Since it compiles packages from source, a full-featured desktop install on a slow machine can take days to finish. This is one of the things I love about the *BSD systems. The package system is two-headed. You an do pkg_add, and it'll act like yum or apt-get, and install binaries for the package and all the requirements for it. Or you can cd to /usr/ports/category/pkg-name and do make install, and it will download, compile and install all the required software and the port you're building (I do that to change the isntalltion prefix on the packages). If you want to create customized packages, you just do make package. I found creating a port (and hence package) to be much easier than creating a .deb or .rpm, but that may just be me. For real control, you can install the portupgrade package. That said, the author of the BSD ports system thinks the architecture is wrong. It handles the building, installation, fetching and requirements all by itself. He thinks the yum/apt-get approach, where one tool handles package installation duties, and another deals with requirements fetching is much saner. mike -- Mike Meyer [EMAIL PROTECTED] http://www.mired.org/home/mwm/ Independent WWW/Perforce/FreeBSD/Unix consultant, email for more information. -- http://mail.python.org/mailman/listinfo/python-list
Re: Python doc problem example: gzip module (reprise)
Andrea Gavana [EMAIL PROTECTED] writes: I tend to agree with you, Rick. I usually don't like Xah's posting behavior, but this time he has done, in my opinion, a constructive criticism (and he didn't even say *fuck* once in the whole post!!!). I am quite a newbie in Python, I usually deal with wxPython that is sometimes not very pythonic, or not enough pythonic. As a newbie (in whatever language you wish), I would like to open the docs about a particular library, class or method and find a small sample application of it. I think many newbies learn by examples. I don't mean to say anything negative about the docs or the docs' authors, but I would imagine that having a simple example of use for all the methods in a class/library would be a nice and valuable improvement for the docs. The thing is, the library documentation that Xah Lee is complaining about is a *reference document*. It says so right in the title: Python Library Reference. As such, it makes lousy tutorial documentation. Xah correctly points this out, which is akin to pointing out that the sky is not green. Now, if he wanted to call the PSF to task for not providing sufficient tutorial documentation, he might have a point. On the other hand, the PSF has limited resources, and: OTOH, usually by using some simple google-fu, it is easy to find a sample application for a particular method. The Python Cookbook should show up a lot in this search. If other people are providing tutorial documentation, then it's not at clear that the PSF should be duplicating that effort. If they had infinite resources, it's clear they should be providng the documentation Xah Lee wants. It doesn't, so letting third parties provide tutorial documentation is probably the best use of the limited resources that they have available. And, since we're talking about Mr. Lee, let's add the obligatory request that you help google find him by description by adding this link to your page: a href=http://xahlee.org/;stupider than spam/a mike -- Mike Meyer [EMAIL PROTECTED] http://www.mired.org/home/mwm/ Independent WWW/Perforce/FreeBSD/Unix consultant, email for more information. -- http://mail.python.org/mailman/listinfo/python-list
Re: Python doc problem example: gzip module (reprise)
Paul Rubin http://[EMAIL PROTECTED] writes: Mike Meyer [EMAIL PROTECTED] writes: The thing is, the library documentation that Xah Lee is complaining about is a *reference document*. It says so right in the title: Python Library Reference. As such, it makes lousy tutorial documentation. I'm not sure which particular library Xah Lee was complaining about but lots of the lib docs are awful even as references. That's true, but Xah Lee's proposed fixes do nothing to address this problem. The Python Cookbook should show up a lot in this search. If other people are providing tutorial documentation, then it's not at clear that the PSF should be duplicating that effort. It seems to me that since the PSF is so persnickety about code licenses (and that is a good thing), it should be persnickety about documentation licenses too. Lots of FSF documentation projects were undertaken because while there were good docs in existence for whatever it was, there were none that the FSF could include in its distros. It's similarly not so great if Python users have to rely on proprietary docs. Of course the PSF has to prioritize its tasks and some things will necessarily stay far down on the list for quite a while, but they should at least BE on the list. To my knowledge the PSF isn't doing anything about including the documentation with their distribution, so they shouldn't care about the licenses. Wanting to bundle a good tutorial for everything in the library might be on the list, but the licenses on third-party tutorials shouldn't matter until you are considering bundling them. In that light, the only major omission I can think of is Tkinter, as the only good docs - tutorial, reference, or otherwise - is the Grayson's book. mike -- Mike Meyer [EMAIL PROTECTED] http://www.mired.org/home/mwm/ Independent WWW/Perforce/FreeBSD/Unix consultant, email for more information. -- http://mail.python.org/mailman/listinfo/python-list
Re: Python doc problem example: gzip module (reprise)
Paul Rubin http://[EMAIL PROTECTED] writes: To my knowledge the PSF isn't doing anything about including the documentation with their distribution, so they shouldn't care about the licenses. Wanting to bundle a good tutorial for everything in the library might be on the list, but the licenses on third-party tutorials shouldn't matter until you are considering bundling them. It's only -because- of those licenses that there's any reason not to bundle. Actually, there are other reasons, just as there are reasons besides licensing for not simply including third party libraries into the standard library. Most important is the issue of maintenance: is someone going to commit to keeping an added document up to date with the distribution? Bundling out of date documentation is a bad thing. Bundling documentation that is going to be left out of the next release because nobody updated it isn't much better. The author of the documentation is the logical person to do this, but if they wanted the documentation bundled with Python, they probably would have submitted it as a PR (I know that's what I do for OSS projects). In that light, the only major omission I can think of is Tkinter, as the only good docs - tutorial, reference, or otherwise - is the Grayson's book. I found http://infohost.nmt.edu/tcc/help/lang/python/tkinter.html to be a pretty good tutorial, though incomplete as a reference. Thanks for the URL, but that's just a short list of links, most of which I've already seen. mike -- Mike Meyer [EMAIL PROTECTED] http://www.mired.org/home/mwm/ Independent WWW/Perforce/FreeBSD/Unix consultant, email for more information. -- http://mail.python.org/mailman/listinfo/python-list
Re: Python doc problem example: gzip module (reprise)
Paul Rubin http://[EMAIL PROTECTED] writes: Mike Meyer [EMAIL PROTECTED] writes: It's only -because- of those licenses that there's any reason not to bundle. Actually, there are other reasons, just as there are reasons besides licensing for not simply including third party libraries into the standard library. I'm not talking about 3rd party libraries, I'm talking about 3rd party documentation for modules that are already in the Python standard library. So am I. My point is that many of the considerations as to why you don't simply include a module in the library also apply when it comes to including documentation in the distribution. I gave some examples, including why they were important for *documentation*, but you carefully elided those. For example, if someone wrote a good Tkinter manual that were licensed in a way that the PSF could drop it into the Python distro, then PSF should certainly consider including it. The same goes for good docs about urllib2, or various other modules that currently have lousy docs. The key word is consider. They have to deal with all the issues I pointed out before, of which licensing is just the beginning. Sorry, I meant: http://infohost.nmt.edu/tcc/help/pubs/tkinter/ (html) http://www.nmt.edu/tcc/help/pubs/tkinter.pdf (pdf of same) You've probably seen this manual already. Yes, I have. I still say the only good documentation is Grayson's book. mike -- Mike Meyer [EMAIL PROTECTED] http://www.mired.org/home/mwm/ Independent WWW/Perforce/FreeBSD/Unix consultant, email for more information. -- http://mail.python.org/mailman/listinfo/python-list
Re: Class Variable Access and Assignment
Antoon Pardon [EMAIL PROTECTED] writes: Op 2005-11-03, Mike Meyer schreef [EMAIL PROTECTED]: Antoon Pardon [EMAIL PROTECTED] writes: What would you expect to get if you wrote b.a = b.a + 2? I would expect a result consistent with the fact that both times b.a would refer to the same object. Except they *don't*. This happens in any language that resolves references at run time. Python doesn't resolve references at run time. If it did the following should work. You left out a key word: all. a = 1 def f(): a = a + 1 f() If Python didn't resolve references at run time, the following wouldn't work: def f(): ... global a ... a = a + 1 ... a = 1 f() But letting that aside. There is still a difference between resolving reference at run time and having the same reference resolved twice with each resolution a different result. The second is a direct result of the first. The environment can change between the references, so they resolve to different results. Changing that would be changing a fundamental - and *important* - feature of Python. Arbitrary restrictions to prevent a single case of this from doing something people who aren't used to suvh behavior are kludges, and would constitute a wart on the language, pure and simple. Python already has its warts. If you want to argue that fixing this would make a bigger wart then the wart it is now. Fine I will accept that. I've already argued that the kludges suggested to solve this problem create worse problems than this. This is a simple case of something being unexpected to those used to less dynamic languages. The other solutions break useful functionality, and require adding special cases to the language - which aren't special enough to break the rules. mike -- Mike Meyer [EMAIL PROTECTED] http://www.mired.org/home/mwm/ Independent WWW/Perforce/FreeBSD/Unix consultant, email for more information. -- http://mail.python.org/mailman/listinfo/python-list
Re: Class Variable Access and Assignment
Would it be too much to ask that in a line like. x = x + 1. both x's would resolve to the same namespace? Yes. That's to much bondage for programmers who've become accustomed to freedom. Explain why this should be illegal: class C: ... def __getattr__(self, name): ... x = 1 ... return locals()[name] ... def __setattr__(self, name, value): ... globals()[name] = value ... o = C() o.x = o.x + 1 x 2 mike -- Mike Meyer [EMAIL PROTECTED] http://www.mired.org/home/mwm/ Independent WWW/Perforce/FreeBSD/Unix consultant, email for more information. -- http://mail.python.org/mailman/listinfo/python-list
Re: Class Variable Access and Assignment
Paul Rubin http://[EMAIL PROTECTED] writes: Mike Meyer [EMAIL PROTECTED] writes: I've already argued that the kludges suggested to solve this problem create worse problems than this. The most obvious solution is to permit (or even require) the programmer to list the instance variables as part of the class definition. Anything not in the list is not an instance variable, i.e. they don't get created dynamically. That's what most other languages I can think of do. Some Python users incorrectly think this is what __slots__ does, and try to use __slots__ that way. That they try to do that suggests that the approach makes some sense. That breaks the ability to add attributes dynamically, which is usefull. If you need an extra piece of data with some existing class, it's much easier to just add an attribute to hold it than to create a subclass for the sole purpose of adding that attribute. mike -- Mike Meyer [EMAIL PROTECTED] http://www.mired.org/home/mwm/ Independent WWW/Perforce/FreeBSD/Unix consultant, email for more information. -- http://mail.python.org/mailman/listinfo/python-list
Re: Class Variable Access and Assignment
Antoon Pardon [EMAIL PROTECTED] writes: Op 2005-11-04, Mike Meyer schreef [EMAIL PROTECTED]: Would it be too much to ask that in a line like. x = x + 1. both x's would resolve to the same namespace? Yes. That's to much bondage for programmers who've become accustomed to freedom. Explain why this should be illegal: class C: ... def __getattr__(self, name): ... x = 1 ... return locals()[name] ... def __setattr__(self, name, value): ... globals()[name] = value ... o = C() o.x = o.x + 1 x 2 I'll answer with a contra question. Please explain why this is illegal. x = 1 def f(): x += 1 f() It isn't illegal, it just requires a different syntax. mike -- Mike Meyer [EMAIL PROTECTED] http://www.mired.org/home/mwm/ Independent WWW/Perforce/FreeBSD/Unix consultant, email for more information. -- http://mail.python.org/mailman/listinfo/python-list
Re: Class Variable Access and Assignment
Antoon Pardon [EMAIL PROTECTED] writes: Op 2005-11-04, Mike Meyer schreef [EMAIL PROTECTED]: Antoon Pardon [EMAIL PROTECTED] writes: Op 2005-11-03, Mike Meyer schreef [EMAIL PROTECTED]: Antoon Pardon [EMAIL PROTECTED] writes: What would you expect to get if you wrote b.a = b.a + 2? I would expect a result consistent with the fact that both times b.a would refer to the same object. Except they *don't*. This happens in any language that resolves references at run time. Python doesn't resolve references at run time. If it did the following should work. You left out a key word: all. a = 1 def f(): a = a + 1 f() If Python didn't resolve references at run time, the following wouldn't work: def f(): ... global a ... a = a + 1 ... a = 1 f() Why do you think so? I see nothing here that couldn't work with a reference resolved during compile time. a - in the global name space - doedn't exist when f is compiled, and hence can't be dereferenced at compile time. Of course, sufficiently advanced analysis can figure out that a would exist before f is run, but that's true no matter how a is added. That isn't the way python works. But letting that aside. There is still a difference between resolving reference at run time and having the same reference resolved twice with each resolution a different result. The second is a direct result of the first. The environment can change between the references, so they resolve to different results. No the second is not a direct result of the first. Since there is only one reference, I see nothing wrong with the environment remebering the reference and reusing it if it needs the reference a second time. Please stay on topic: we're talking about a = a + 1, not a += 1. The former has two references, not one. I've already agreed that the semantics of += are a wart. mike -- Mike Meyer [EMAIL PROTECTED] http://www.mired.org/home/mwm/ Independent WWW/Perforce/FreeBSD/Unix consultant, email for more information. -- http://mail.python.org/mailman/listinfo/python-list
Re: Class Variable Access and Assignment
Steven D'Aprano [EMAIL PROTECTED] writes: equal? Some things are a matter of objective fact: should CPython use a byte-code compiler and virtual machine, or a 1970s style interpreter that interprets the source code directly? For the record, I've only seen one interpreter that actually interpreted the source directly. Pretty much all of the rest of them do a lexical analysis, turning keywords into magic tokens (dare I say byte codes) and removing as much white space as possible. Or maybe that's what you meant? mike -- Mike Meyer [EMAIL PROTECTED] http://www.mired.org/home/mwm/ Independent WWW/Perforce/FreeBSD/Unix consultant, email for more information. -- http://mail.python.org/mailman/listinfo/python-list
Re: Class Variable Access and Assignment
[EMAIL PROTECTED] (Bengt Richter) writes: On Thu, 03 Nov 2005 13:37:08 -0500, Mike Meyer [EMAIL PROTECTED] wrote: [...] I think it even less sane, if the same occurce of b.a refers to two different objects, like in b.a += 2 That's a wart in +=, nothing less. The fix to that is to remove += from the language, but it's a bit late for that. Hm, the fix? Why wouldn't e.g. treating augassign as shorthand for a source transformation (i.e., asstgt op= expr becomes by simple text substitution asstgt = asstgt op expr) be as good a fix? Then we could discuss what b.a = b.a + 2 should mean ;-) The problem with += is how it behaves, not how you treat it. But you can't treat it as a simple text substitution, because that would imply that asstgt gets evaluated twice, which doesn't happen. OTOH, we could discuss how you can confuse yourself with the results of b.a += 2 after defining a class variable a as an instance of a class defining __iadd__ ;-) You may confuse yourself that way, I don't have any problems with it per se. Or point out that you can define descriptors (or use property to make it easy) to control what happens, pretty much in as much detail as you can describe requirements ;-) I've already pointed that out. mike -- Mike Meyer [EMAIL PROTECTED] http://www.mired.org/home/mwm/ Independent WWW/Perforce/FreeBSD/Unix consultant, email for more information. -- http://mail.python.org/mailman/listinfo/python-list
Re: Class Variable Access and Assignment
[EMAIL PROTECTED] (Bengt Richter) writes: On 04 Nov 2005 17:53:34 -0800, Paul Rubin http://[EMAIL PROTECTED] wrote: [EMAIL PROTECTED] (Bengt Richter) writes: Hm, the fix? Why wouldn't e.g. treating augassign as shorthand for a source transformation (i.e., asstgt op= expr becomes by simple text substitution asstgt = asstgt op expr) be as good a fix? Then we could discuss what Consider a[f()] += 3. You don't want to eval f() twice. Well, if you accepted macro semantics IWT you _would_ want to ;-) Another one of those throw-away lines. I'd say that was true only if the macro was poorly written. Unless a macros is intended as a tool to repeatedly evaluate an argument, it should only evaluate it at most once. Of course, if you're using some rock-stupid textual macro system, you really don't have much choice in the matter. mike -- Mike Meyer [EMAIL PROTECTED] http://www.mired.org/home/mwm/ Independent WWW/Perforce/FreeBSD/Unix consultant, email for more information. -- http://mail.python.org/mailman/listinfo/python-list
Re: Class Variable Access and Assignment
Paul Rubin http://[EMAIL PROTECTED] writes: Steven D'Aprano [EMAIL PROTECTED] writes: It also allows you to do something like this: class ExpertGame(Game): current_level = 100 and then use ExpertGame anywhere you would have used Game with no problems. Well, let's say you set, hmm, current_score = 100 instead of current_level. Scores in some games can get pretty large as you get to the higher levels, enough so that you start needing long ints, which maybe are used elsewhere in your game too, like for the cryptographic signatures that authenticate the pieces of treasure in the dungeon. Next you get some performance gain by using gmpy to handle the long int arithmetic, and guess what? Eventually a version of your game comes along that enables the postulated (but not yet implemented) mutable int feature of gmpy for yet more performance gains. So now, current_score += 3000 increments the class variable instead of creating an instance variable, and whoever maintains your code by then now has a very weird bug to track down and fix. I'd say that's a wart with +=, not with Python's inheritance mechanisms. += is neither + nor =, but takes on different aspects of each depending on what it's operating on. While it's true that python is dynamic enough that the you can create classes that make this true for any operator, += is the only one that acts like that on the builtin types. mike -- Mike Meyer [EMAIL PROTECTED] http://www.mired.org/home/mwm/ Independent WWW/Perforce/FreeBSD/Unix consultant, email for more information. -- http://mail.python.org/mailman/listinfo/python-list
Re: re sub help
[EMAIL PROTECTED] writes: hi i have a string : a = this\nis\na\nsentence[startdelim]this\nis\nanother[enddelim]this\nis\n inside the string, there are \n. I don't want to substitute the '\n' in between the [startdelim] and [enddelim] to ''. I only want to get rid of the '\n' everywhere else. Well, I'm not an expert on re's - I've only been using them for three decades - but I'm not sure this can be done with a single re, as the pattern you're interested in depends on context, and re's don't handle that well. On the -- Mike Meyer [EMAIL PROTECTED] http://www.mired.org/home/mwm/ Independent WWW/Perforce/FreeBSD/Unix consultant, email for more information. -- http://mail.python.org/mailman/listinfo/python-list
Re: re sub help
[EMAIL PROTECTED] writes:
hi
i have a string :
a =
this\nis\na\nsentence[startdelim]this\nis\nanother[enddelim]this\nis\n
inside the string, there are \n. I don't want to substitute the '\n'
in between
the [startdelim] and [enddelim] to ''. I only want to get rid of the
'\n' everywhere else.
Well, I'm not an expert on re's - I've only been using them for three
decades - but I'm not sure this can be done with a single re, as the
pattern you're interested in depends on context, and re's don't handle
that well.
On the other hand, this is fairly straightforward with simple string
operations:
a = this\nis\na\nsentence[startdelim]this\nis\nanother[enddelim]this\nis\n
sd = '[startdelim]'
ed = '[enddelim]'
s, r = a.split(sd, 1)
m, e = r.split(ed, 1)
a = s + sd + m.replace('\n', '') + ed + e
a
'this\nis\na\nsentence[startdelim]thisisanother[enddelim]this\nis\n'
mike
--
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Independent WWW/Perforce/FreeBSD/Unix consultant, email for more information.
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Re: Getting a function name from string
[EMAIL PROTECTED] (Bengt Richter) writes: For a lot of uses, it'd be better to build the dictionary by hand rather than relying on one of the tools that turns a namespace into a dictionary. IMO it would be nice if name lookup were as cleanly controllable and defined as attribute/method lookup. Is it a topic for py3k? I'm not sure what you mean by cleanly controllable and defined. I'd say name lookup is well defined and clean, as it's the same as it is in pretty much any language that supports nested scopes, modulo assignment creating things in the local scope. If you're talking about letting users control that mechanism, that's definitely py3k material, if not python-like-language-that's-not-python material. On the other hand, if you just want to provide tools that let users do name lookups the way they can do attribute lookups, that's easy, and we could add that now: getname(name) - returns the object name is bound to. setname(name, value) - binds the variable name. And maybe you want an optional third argument of a callable, which causes the functions to work on names starting in the callables name space. The real question is (as always) - what's the use case? In particular, what's the use case that we really want to encourage? As I said, you're usually better off separating dynamically built names into their own dictionary rather than trying to plug them into - or pull them out of - one of the language namespaces. If you plug them in, there's no way to get them back out except by mechanisms similar to how you got them in, so you might as well let those mechanisms include a dictionary. If you pull it out, you might as well have referenced the bare name rather than the string. If you constructed the name in some way, then changing the constructor to do a dictionary lookup should be straightforward. All of these technics avoid problems that come from overloading a language namespace. Of course, I'm not omniscient, so you may have something that doesn't fit those cases in mind - in which case, let's hear about it. You can even arrange to run python code with your dictionary as a namespace. Following are excerpts from a tool I'm currently not working on. class P: def __init__(self): self.variables = dict(In = self.set_input, Out = self.set_output, Labels = self.set_labels, Float = DoubleVar, String = StringVar, Int = IntVar) def calculate(self): for name, var in self.inputs.items(): self.variables[name] = var.get() self.variables['calculate']() for name, var in self.outputs.items(): var.set(self.variables[name]) def run(self): self.app.mainloop(self.calculate) def main(args): app = P() execfile(argv[1], app.variables) app.run() Here I create a dictionnary - P().variables - and populate it with names and their values. I then run the code of interest with that dictionary as the global namespace. The code will add things to the namespace - in particular, calculate. I then run a loop which will, at unspecified times, set names in the P().variables dictionary, run the calculate callable created by the code of interest, then copy values out of the dictionary. This works ilke a charm. If you don't want to deal with entire files, you can use exec, or even eval if you just want to get a value back. mike -- Mike Meyer [EMAIL PROTECTED] http://www.mired.org/home/mwm/ Independent WWW/Perforce/FreeBSD/Unix consultant, email for more information. -- http://mail.python.org/mailman/listinfo/python-list
Re: Class Variable Access and Assignment
Antoon Pardon [EMAIL PROTECTED] writes: What would you expect to get if you wrote b.a = b.a + 2? I would expect a result consistent with the fact that both times b.a would refer to the same object. Except they *don't*. This happens in any language that resolves references at run time. Changing that would be changing a fundamental - and *important* - feature of Python. Arbitrary restrictions to prevent a single case of this from doing something people who aren't used to suvh behavior are kludges, and would constitute a wart on the language, pure and simple. If you think this is bad, you should consider Jensen's device. It uses call-by-name, which Python doesn't have. This defers evauation of an argument until the actual use of the argument. You can fake it in python by passing strings that you eval and/or lambdas that you call - I'm not going to work out the details. Here's the function: real procedure SIGMA(x, i, n); value n; real x; integer i, n; begin real s; s := 0; for i := 1 step 1 until n do s := s + x; SIGMA := s; end The object referred to by x in the body of the loop is different *every pass through the loop*, at least in the expected usage. That usage is SIGMA(a(i), i, 10). Call-by-name evaluates a(i) when x is mentioned. Since i changes with each pass through the loop, a(i) is a different element in the array. So SIGMA(a(i), i, 10) is sum(a[:10]) (give or take). But SIGMA(a(i) * b(i), i, 10) is sum([a(i) * b(i) for i in xrange(10)]) (more or less). This isn't insane, it's a feature. It's a *very powerful* feature. Yes, it causes behavior that's unexpected and appears to be wrong to people who aren't used to resolving names at run time. They need to get used to it. Then they can start taking advantage of it. I think it even less sane, if the same occurce of b.a refers to two different objects, like in b.a += 2 That's a wart in +=, nothing less. The fix to that is to remove += from the language, but it's a bit late for that. mike -- Mike Meyer [EMAIL PROTECTED] http://www.mired.org/home/mwm/ Independent WWW/Perforce/FreeBSD/Unix consultant, email for more information. -- http://mail.python.org/mailman/listinfo/python-list
Re: Can Anyone Help me on this
[EMAIL PROTECTED] writes: If what you want is a reversed copy, you could just append list1 elements to list2, and use the reverse function such as ... for i in list1: ... list2.append(i) ... Don't do this by ahnd - let python do it for you: list2 = list(list1) or list2 = list1[:] mike list2.reverse() list1 ['1', '2', '3', '4', '5', '6', '7', '8', '9'] list2 ['9', '8', '7', '6', '5', '4', '3', '2', '1'] -- Mike Meyer [EMAIL PROTECTED] http://www.mired.org/home/mwm/ Independent WWW/Perforce/FreeBSD/Unix consultant, email for more information. -- http://mail.python.org/mailman/listinfo/python-list
Re: Class Variable Access and Assignment
Graham [EMAIL PROTECTED] writes: I just seems to me that instance.var shouldn't defer to the class variable if an instance variable of the same name does not exists, it should, at least how i understand it raise an exception. Is my thinking way off here? Yes. This behavior is how you get inheritted access to class variables. Consider: class Counter(object): A mutable counter. # implementation elided class A(object): instance_count = Counter() def __init__(self): self.instance_count.increment() class B(A): instance_count = Counter() This is sufficient to count instances of A and B. If self.instance_count raised an exception, you'd have to do something like A.instance_count in A.__init__, which would mean the __init__ B inherited from A would do the wrong thing. Currently, you can either reference class variables by explicit class, or via inheritance, and both behaviors are desirable. If you're going to disallow self.class_variable, you need to come up with a mechanism to replace the latter behavior. mike -- Mike Meyer [EMAIL PROTECTED] http://www.mired.org/home/mwm/ Independent WWW/Perforce/FreeBSD/Unix consultant, email for more information. -- http://mail.python.org/mailman/listinfo/python-list
Re: Class Variable Access and Assignment
Graham [EMAIL PROTECTED] writes: Many thanks your explaination cleared up many of the questions I had. I know think i can understand the purpose, regardless of my opinion, i do however think that one should be able to assign the value in the same way it is accessed. That's not true in lots of cases, and would be a serious restriction on the language. The rules for where a binding takes place are the way the are for good reason. Restricting lookups to those rules would make a number of things more difficult, and would make some features (cough-closures-cough) nearly useless. Given your previous example: class Counter(object): A mutable counter. # implementation elided class A(object): instance_count = Counter() def __init__(self): self.instance_count.increment() if you changed class A(object): instance_count = Counter() def __init__(self): self.instance_count.increment() to class A(object): instance_count = 0 def __init__(self): self.instance_count = self.instance_count + 1 It would not work as planned. I understand all the reasons why this occurs, but i dont understand why its implemented this way. Because it acts in a different way than you expect. No, it acts in a different way than *you* expect. It does exactly what I expect, which is why I didn't write it that way. It seems to me that self.instance_count should not create a new entry in the __dict__ if a class variable of that name is already present anywhere in that objects hierarchy. Does that make sense? Yes, but such behavior would make Python worse, not better. Right now, binding instance.name *always* works(*) on the value of the name attribute of instance. Creating a special case for when one of the classes instance belongs to happens to have an attribute name would be less consistent than the current behavior. Yes, the current behavior is surprising to people who aren't used to dynamic languages. But there are lots of such things - they're part of the power of dynamic languages. People who want to program in dynamic languages just have to get used to those things. That's a lesser price to pay than having a language cluttered with special cases just to avoid surprising people who aren't used to the language yet. Again thank you for explaination. You're welcome. mike *) I almost said binds, but that's not true. Attempting to bind an attribute can invoke arbitrary code - but it's got the instance and attribute name to work with. If you really wanted to, you could create a class for which trying to set an attribute behaved as you wanted. Be warned - it's not as easy as it looks. -- Mike Meyer [EMAIL PROTECTED] http://www.mired.org/home/mwm/ Independent WWW/Perforce/FreeBSD/Unix consultant, email for more information. -- http://mail.python.org/mailman/listinfo/python-list
Re: If Statement Error (Tic Tac Toe)
[EMAIL PROTECTED] writes: Nevermind my previous reply: I've been fixing up the code and understand it. I'm at a nifty 80 lines where I am at now rather than 209 lines in the previous version! The changes are immense! The only problem I have is whenever player two goes, it says the cell is filled. But the code: if gameboard[cell] not in 'OX': gameboard[cell] = 'X' else: print This cell is already filled. turnnumber = turnnumber - 1 is not any different than the code I am using for player one. Anything I have to change regarding 'OX' or something else? Make sure you're setting cell properly - you didn't show that. Also, the above code is a syntax error; I assume your running code has the correct indentation. mike -- Mike Meyer [EMAIL PROTECTED] http://www.mired.org/home/mwm/ Independent WWW/Perforce/FreeBSD/Unix consultant, email for more information. -- http://mail.python.org/mailman/listinfo/python-list
Re: Xah's edu corner: the Journey of Foreign Characters thru Internet
Peter Hansen [EMAIL PROTECTED] writes: Mike Meyer wrote: Xah Leh is incompetent, but apparently well-intentioned. In your view is that (well-intentioned) an established fact at this point? I was still waiting for conclusive evidence. No, it's not an established fact, which is why I said apparently. I think *he* thinks he is doing the world a favor by ignoring established netiquette in his postings. But he's clearly incompetent, and that's sufficient to explain his behavior. And there's a saying about malice and incompetence. mike -- Mike Meyer [EMAIL PROTECTED] http://www.mired.org/home/mwm/ Independent WWW/Perforce/FreeBSD/Unix consultant, email for more information. -- http://mail.python.org/mailman/listinfo/python-list
Re: If Statement Error (Tic Tac Toe)
[EMAIL PROTECTED] writes: The code's indentation was fine - I forgot to declare cell in player two's section and not just in player one. The code (including the win check, for once!) is working. The last obstacle is my tie checker; it doesn't seem to like what I have: if ((gameboard[0:9] is 'X' or 'O') and (win == 0)): print Tie. win = 2 Will the [0:9] range not work in this? Should I write out each option? Or is there some way to check if all things in the list are NOT ' '? I tried if ((gameboard[0:9] is not ' ')) Yes, those tests are not doing what you want them to do. On the other hand, you can still test this in one swell foop with in: if ' ' not in gameboard and win == 0: print Tie. win = 2 That does assume that gameboard and gameboard[0:9] are the same thing. But they should be. For that matter, the defaults for the slice should be 0 and 9, so that gameboard[:] is the same thing yet again. But since you're not changing the board but reading it, there's no need to make a copy, which is what the sliced versions do. mike -- Mike Meyer [EMAIL PROTECTED] http://www.mired.org/home/mwm/ Independent WWW/Perforce/FreeBSD/Unix consultant, email for more information. -- http://mail.python.org/mailman/listinfo/python-list
Re: dictionary that have functions with arguments
[EMAIL PROTECTED] writes:
hi
i have a dictionary defined as
execfunc = { 'key1' : func1 }
to call func1, i simply have to write execfunc[key1] .
but if i have several arguments to func1 , like
execfunc = { 'key1' : func1(**args) }
how can i execute func1 with variable args?
using eval or exec?
Whenever you think should I use eval or exec for this, you should
*immediately* stop and think What am I doing wrong?.
Others have suggested using a tuple to hold the function and
arguments, and pointed out the mistake in your invocation.
Whenever you're thinking about doing an evalu with a fixed string, you
can replace it with a lambda. That looks like:
execfunc = dict(key1 = lambda: func1('hello'))
def func1(x): print x
...
execfunc['key1']()
hello
You can use the tuple format, and then use apply and the extended call
syntax to keep it in one line:
execfunc = dict(key1 = (func1, ('hello',)))
apply(*execfunc['key1'])
hello
Note that applly is depreciated - you're supposed to use the extended
call syntax instead. This particular use case for apply can't be
handled by the extended call syntax.
Using dictionaries instead of a fixed arg is a trivial change to both
these examples.
mike
--
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Independent WWW/Perforce/FreeBSD/Unix consultant, email for more information.
--
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Re: how to check for unix password
[EMAIL PROTECTED] writes: i created a login page that authenticate the user and his/her password to the unix ssystem. what modules can i used to compare the unix password with what the user typed in the cgi form? the password is encrypted (shadowed) so i need to decrypt it first before comparing to what the user typed. or this cannot be done at all? As has already been pointed out, users authenticate to Unix systems with a lot more than passwords. Also, it's not a good idea to make a web page use a system password. Web page passwords tend to be poorly protected. Finally, you can't decrypt a Unix password file password. The algorithm is to encrypt what the user typed (with crypt.crypt) then compare that with the entry in the password file. You pass crypt.crypt the user-entered pasword as the first argument, and the password from the password file as the second, and compare the returned value to the password from the password file. mike -- Mike Meyer [EMAIL PROTECTED] http://www.mired.org/home/mwm/ Independent WWW/Perforce/FreeBSD/Unix consultant, email for more information. -- http://mail.python.org/mailman/listinfo/python-list
Re: Most efficient way of storing 1024*1024 bits
Tor Erik Sønvisen [EMAIL PROTECTED] writes: I need a time and space efficient way of storing up to 6 million bits. Time efficency is more important then space efficency as I'm going to do searches through the bit-set. Six megabytes is pretty much nothing on a modern computer. I'd store the things as a string of 0 and 1, and then use .find (or maybe the in keyword) for doing the searches. This doesn't work very well if you're going to mutate the string, though. mike -- Mike Meyer [EMAIL PROTECTED] http://www.mired.org/home/mwm/ Independent WWW/Perforce/FreeBSD/Unix consultant, email for more information. -- http://mail.python.org/mailman/listinfo/python-list
Re: How to print random strings
[EMAIL PROTECTED] writes: Im at the end of chapter 3 of Python Programming For The Absolute Beginner, Michael Dawson and he asks to make a fortune program that displays a fortune each time its ran, and to have 5 unique fortunes. Whats confusing is that, he never discussed how to do this. The only thing he talked about was using random.randrange() and I tried that with text but it seems like its only for integers as it complains when I put text in the argument. So how would I go about have 5 strings, and running a program that will randomly pick one of those to print? I think he may have forgot to cover something? Well, randrange can be used to do this, but random.choice is more pythonic. mike -- Mike Meyer [EMAIL PROTECTED] http://www.mired.org/home/mwm/ Independent WWW/Perforce/FreeBSD/Unix consultant, email for more information. -- http://mail.python.org/mailman/listinfo/python-list
Re: another beginner sort of question
John Salerno [EMAIL PROTECTED] writes: [Wants to learn C# and Python simultaneously.] So my question is, is this feasible? Should be. It might be faster to do them sequentually. Or does learning Python require (or entail) learning all the details behind it? Not really. There are some traps you can fall into that are obvious if you know how the underlying implementation works, but even for those, you just need the general idea, not the details. Also, do I need to know anything about C or C++? No. In fact, the less you know about them, the less you'll have to unlearn to use Python effectively. Python seems to connected to those languages that I'm afraid learning Python by itself might not be practical, but hopefully that's unfounded. CPython (the implementation most people mean when they say Python) is written in C, and has well-defined APIs for putting an interpreter into a C program, or making functionality from a C library available to a CPython program. Other implementations have similar hooks for different languages. Unless you want to get into the internals of an implementation, to embed Python in an application, or to write a Python extension (usually because you're wrapping an existing library), you won't need to worry about any of these. One thing. While Python is called a scripting language, it doesn't have facilities for dealing with shell scripting that other scripting languages have. As such, it's harder to do shell scripting type things in Python than in those languages. On the other hand, it's easier than doing them in C, for the same reason that doing pretty much anything in Python is easier than doing it in C. On the gripping hand, if you do things pythonically instead of like you'd do them in a shell script, you may find that Python is easier than the shell script. mike -- Mike Meyer [EMAIL PROTECTED] http://www.mired.org/home/mwm/ Independent WWW/Perforce/FreeBSD/Unix consultant, email for more information. -- http://mail.python.org/mailman/listinfo/python-list
Re: Pychecker Re: Nested List Question
Roman Suzi [EMAIL PROTECTED] writes: On Thu, 3 Nov 2005, Chris McCoy wrote: gridSystemId = [[None]*columns]*rows You've made gridSystemID a list of `rows` references to the SAME inner list, so the behavior you observe is the only possible one. If you want copies instead, ASK for copies...: gridSystemId = [ [None]*columns for x in xrange(rows) ] Interesting, could not pychecker recognize such situations in Python code and give warnings? Well, it could always just issue warnings everytime it saw a list multiplied by something. But that would get annoying in the cases where that idiom doesn't have problems - which is naturally most such usages. Your example included one such, which is why the translation wasn't to: gridSystemId = [[None for y in xrange(columns)] for x in xrange(rows)] WRONG [None] * columns doesn't have problems. Nor does any other immutable object. So to avoid spurious warnings, pychecker would have to know whether the objects in the list were immutable or not. It could guess that if the objects are builtin types, but not for other types. mike -- Mike Meyer [EMAIL PROTECTED] http://www.mired.org/home/mwm/ Independent WWW/Perforce/FreeBSD/Unix consultant, email for more information. -- http://mail.python.org/mailman/listinfo/python-list
Re: Xah's edu corner: the Journey of Foreign Characters thru Internet
[EMAIL PROTECTED] writes: Interesting opinions this man has, I must say. A Sith of Computing he may be? No. Sith are competent but evil. Xah Leh is incompetent, but apparently well-intentioned. Some of his opinions are correct, but that appears to be more by accident than anything else, and there's no easy way to distinguish those from his usual work. He has been accurately described as stupider than spam. Please help Google find him that way by adding an appropriater link to your web site: a href=http://xahlee.org/;stupider than spam/a mike -- Mike Meyer [EMAIL PROTECTED] http://www.mired.org/home/mwm/ Independent WWW/Perforce/FreeBSD/Unix consultant, email for more information. -- http://mail.python.org/mailman/listinfo/python-list
Re: extracting numbers from a file, excluding words
Kristina Kudriaðova [EMAIL PROTECTED] writes:
1 Nov 2005 09:19:45 -0800, [EMAIL PROTECTED] [EMAIL PROTECTED]:
Hi, I have a file with this content:
z zzz z
...
xxx xx x 34.215
zzz zz
...
Hi,
I'd suggest doing this:
f = file('...')
for line in f:
if 'xxx xx x' in line:
var = float(line[len('xxx xx x'):].strip())
f.close()
Alternatively:
start = len('xxx xx x')
for line in f:
if line.startswith('xxx xx x'):
var = float(line[start:].strip())
mike
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Re: If Statement Error (Tic Tac Toe)
filled.
turnnumber = turnnumber - 1
if row == 3 and column == 3:
if gameboard[8] != ('O' or 'X'):
gameboard[8] = ('X')
else:
print This cell is already filled.
turnnumber = turnnumber - 1
turnnumber = turnnumber + 1
if (((gameboard[0] and gameboard[1] and gameboard[2]) ==
'X') or ((gameboard[3] and gameboard[4] and gameboard[5]) == 'X') or
((gameboard[6] and gameboard[7] and gameboard[8]) == 'X')\
or ((gameboard[0] and gameboard[3] and gameboard[6]) ==
'X') or ((gameboard[1] and gameboard[4] and gameboard[7]) == 'X') or
((gameboard[2] and gameboard[5] and gameboard[8]) == 'X')\
or ((gameboard[0] and gameboard[4] and gameboard[8]) ==
'X') or ((gameboard[2] and gameboard[4] and gameboard[6]) == 'X')):
print Player 2 wins!
win = 1
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Re: Python's website does a great disservice to the language
CppNewB [EMAIL PROTECTED] writes: My thoughts weren't to add a flash demo or develop some 500K logo or fixing the font size. But the logos look like they were done in Paint and maybe a readable default font is in order. So what's wrong with the fonts they use - where they didn't let your browser pick them, anyway. In the latter case, the fault is yours, not theirs. mike -- Mike Meyer [EMAIL PROTECTED] http://www.mired.org/home/mwm/ Independent WWW/Perforce/FreeBSD/Unix consultant, email for more information. -- http://mail.python.org/mailman/listinfo/python-list
Re: If Statement Error (Tic Tac Toe)
[EMAIL PROTECTED] writes: Thank you. It seems I didn't understand logic statements as much as I thought I did! The one remaining question I have deals with this: if gameboard[cell] not in 'OX': gameboard[cell] = 'O' else: print This cell is already filled. turnnumber -= 1 (gameboard[cell] not in 'OX' is the gameboard[cell] != 'OX' text I sort of used in my code, right?) I am confused about OX: what exactly *is* it? After that, I plan to rewrite all the code... :) OX is a string. Saying shortstring in longstring is one way of asking if shortstring is contained in longstring. In your case, shortstring is one character long, but that's a string to Python. Python doesn't have a distinct character data type. While I'm at it, don't be confused by single quotes vs. double quotes. Unlike other languages, in Python they have the same meaning. The only difference is what you have to do to get a single (double) quote in the string. mike -- Mike Meyer [EMAIL PROTECTED] http://www.mired.org/home/mwm/ Independent WWW/Perforce/FreeBSD/Unix consultant, email for more information. -- http://mail.python.org/mailman/listinfo/python-list
Re: Arguments for button command via Tkinter?
[EMAIL PROTECTED] [EMAIL PROTECTED] writes: Recently, I have been needing to do this alot and I can never find a way around it, the main reason I want to do this is because for example in the application I am making right now, it creates a grid of buttons in a loop and they all have the same purpose so they need to call the same method, within this method they need to change the background color of the button clicked, I've tried stuff like... button['command'] = lambda: self.fill(button) def fill(self, wid): button['bg'] = '#ff' But that's no good, everytime it I do click a button the lambda method I have setup keeps getting recreated so all of the button commands point to the same lambda method, I have also tried appending them to an array, and calling them from that. Anyone have any clue as of what to do? Thanks. People have pointed out how to do this with a class, but you can do it with lambdas as well. I suspect the problem you're having is that python is binding values at call time instead of at definition time, but it's hard to tell without more of your source code. If I'm right, one solution is to make the values you want bound at definition time optional arguments to the lambda, bound to the correct value then. So you'd do: button['command'] = lambda b = button: self.fill(b) The version you used will look up the name button when the lambda is invoked. My version will look it up when the lambda is defined. mike -- Mike Meyer [EMAIL PROTECTED] http://www.mired.org/home/mwm/ Independent WWW/Perforce/FreeBSD/Unix consultant, email for more information. -- http://mail.python.org/mailman/listinfo/python-list
Re: Expanding Python as a macro language
Jorgen Grahn [EMAIL PROTECTED] writes: On 29 Oct 2005 17:25:58 -0700, [EMAIL PROTECTED] [EMAIL PROTECTED] wrote: ... Michel wrote: ... Linux can run perfectly happily without any form of windowing environment. I know, but nowadays almost any relevant application has a GUI. Side note: lots of people would disagree with that. For example, from my perspective, almost all relevant applications /lack/ a GUI. (And some that has one would be better off without it.) This brings up an interesting point for scripting unix applications. One common approach is to provide the application functionaliity in a library, then wrap that in various ways, of which a GUI is only one. You script the application by wrapping the library for your favorite scripting language, and the script will never open a GUI. In fact, it'll work fine in an environment where the GUI couldn't open at all. mike -- Mike Meyer [EMAIL PROTECTED] http://www.mired.org/home/mwm/ Independent WWW/Perforce/FreeBSD/Unix consultant, email for more information. -- http://mail.python.org/mailman/listinfo/python-list
Re: Microsoft Hatred FAQ
David Schwartz [EMAIL PROTECTED] writes: Mike Meyer [EMAIL PROTECTED] wrote in message news:[EMAIL PROTECTED] Microsoft's behavior consisted of arguments, that is, did not involve force, the threat of force, fraud, or the threat of fraud. This is perhaps the most vital distinction that there is. Wrong. Either your definition of force is to narrow, or you're wrong that it's the distinction is even vaguely vital. If I convince everyone who might make food available to you not to do so - for example, by paying them more than their interaction with you is worth to them, I can starve you to death. I'd say I've used force against you - an economic force. Right, you would say that, because you don't see the difference between guns and arguments. Except I'm willing to allow your definition. All it takes is reading the next paragraph for you to see that. Of course, you've dropped the real point, which is your own inabillity to distinguish between, as you put it, guns and arguments. You always act as if every mention of a crime committed by someone other than microsoft involved guns, even when most of them don't. You have as yet to offer any explanation for that other than that you're following MS's orders. This is the kind of force that MS wields illegally. I'm willing to admit this isn't a usual definition of force, and won't argue if you want to say that it isn't force. But in that case, the fact that I didn't use force against you is irrelevant to you - you're just as dead. No, it is completely relevant. You are trying to say the means don't matter if the same end is achieved. But if you're going to say that, you might as well say there's no difference between shooting someone and letting them die of natural causes. Another straw man argument. I'm not trying to say anything of the sort. mike -- Mike Meyer [EMAIL PROTECTED] http://www.mired.org/home/mwm/ Independent WWW/Perforce/FreeBSD/Unix consultant, email for more information. -- http://mail.python.org/mailman/listinfo/python-list
Re: Microsoft Hatred FAQ
David Schwartz [EMAIL PROTECTED] writes: Mike Meyer [EMAIL PROTECTED] wrote in message news:[EMAIL PROTECTED] Of course, you've dropped the real point, which is your own inabillity to distinguish between, as you put it, guns and arguments. You always act as if every mention of a crime committed by someone other than microsoft involved guns, even when most of them don't. You have as yet to offer any explanation for that other than that you're following MS's orders. Your sole evidence for this claim is that I once equated theft with force. Yes, you are correct that it's possible to steal something without using force. Even in this case, from context, it was quite clear that forceful theft was intended. No, my evidence for this claim, as I've repeatedly pointed out, is that *every* time someone compares MS with any other criminal activity, you whine about guns and refuse to deal with the issue. You've gone from claiming that you don't do this, to claiming you only do this when people refer to guns, to ducking the issue. There is a fundamental category difference between the fundamental inter-personal wrongs of force and fraud and every other invented wrong. People are making a concerted attempt in this thread to obliterate that distinction, and I include you in those making that attempt. Another straw man. I'm not trying to oblitarate that difference, I'm trying to find out why you regularly ignore that difference for everyone but MS. You respond by falsely claiming that you aren't doing so, or by ducking the issue. mike -- Mike Meyer [EMAIL PROTECTED] http://www.mired.org/home/mwm/ Independent WWW/Perforce/FreeBSD/Unix consultant, email for more information. -- http://mail.python.org/mailman/listinfo/python-list
Re: Microsoft Hatred FAQ
David Schwartz [EMAIL PROTECTED] writes: I'm trying to find out why you regularly ignore that difference for everyone but MS. To substantiate that claim, you'd have to point to some cases where I talk about something other than MS. You do that *every time* someone compares MS with other criminals - you immediately refer to criminals with guns and refuse to discuss the issue further. And yes, you've already claimed that you only do that when the other reference is to actual use of force, and I've already disproved that. But if you do a little research, you'll find I'm completely consistent and have said similar things about numerour other entities. Not in this thread, you haven't. The only consistency here has been trying to treat MS's crimes as somehow different from other peoples crimes. I'm still waiting for you to quit trying to lie (or, as you would say, argue) your way out of it, and come up with a reason for this behavior other than doing so at MS's orders. mike -- Mike Meyer [EMAIL PROTECTED] http://www.mired.org/home/mwm/ Independent WWW/Perforce/FreeBSD/Unix consultant, email for more information. -- http://mail.python.org/mailman/listinfo/python-list
Re: Microsoft Hatred FAQ
David Schwartz [EMAIL PROTECTED] writes: Mike Meyer [EMAIL PROTECTED] wrote in message news:[EMAIL PROTECTED] David Schwartz [EMAIL PROTECTED] writes: I'm trying to find out why you regularly ignore that difference for everyone but MS. To substantiate that claim, you'd have to point to some cases where I talk about something other than MS. You do that *every time* someone compares MS with other criminals - you immediately refer to criminals with guns and refuse to discuss the issue further. And yes, you've already claimed that you only do that when the other reference is to actual use of force, and I've already disproved that. You have not disproved that. The closest you've come to a disproof is one case where the word theft was used (while earlier in the thread, actual physical force had been used, but not in that specific spot) where the context strongly suggested that it meant theft by force. Now you're simply lieing. I never discussed force earlier in the thread. You are correct that it is possible to steal something without actually using physical force. But that's not an important difference. The hugely important difference, and the one that you and others *are* seeking to obliterate, is the difference between inherently unjust actions such as force and fraud and actions that are neither forceful nor fraudulent. And now you change your story again. You've gone from referring to all other criminal acts as criminals with guns to actual use of force to using force or fraud. The only consistency here has been trying to treat MS's crimes as somehow different from other peoples crimes. That's because the only crimes that have come up in this thread are Microsoft's crimes (that don't involve force or fraud) and other crimes (such as theft, threats of force, and the like) which do. Duh. Actually, they don't necessarily, but that's relevant. You simply label *all* crime other than MS's as criminals with guns and refuse to discuss them. There were a few narrow cases where Microsoft was actually accused of actions that I do consider force or fraud. That's true. They committed a fraud - by lieing to federal officials in court - and *you* responded by calling those federal officials criminals with guns, and using that to *excuse* MS's criminal acts in this case. Which is more of the same old song and dance from you: treating MS's criminal acts as somehow different from any other criminals acts. mike -- Mike Meyer [EMAIL PROTECTED] http://www.mired.org/home/mwm/ Independent WWW/Perforce/FreeBSD/Unix consultant, email for more information. -- http://mail.python.org/mailman/listinfo/python-list
Re: Automatic binding of **kwargs to variables
[EMAIL PROTECTED] [EMAIL PROTECTED] writes: Peter Hansen wrote: Do you mean this instead? elif name in expected_form1_kwargs and name not in kwargs: What you wrote doesn't do what you think it does... it actually tests for whether True or False is a key in kwargs, depending on whether name in expected_form1_kwargs returns True or False. Hi Peter, you're right... the code needed also other fixes and I didn't find a way to do it other than this: def foo(**kwargs): expected_form1_kwargs = [arg1, arg2] for name in expected_form1_kwargs: if name not in kwargs: kwargs[name]=None for name in kwargs: if name in kwargs and name not in expected_form1_kwargs: raise ValueError, Unrecognized keyword: + name print kwargs You're contorting things horribly, and - not unexpected when you do that kind of thing - running code that has no effect. To wit, the second loop goes through every key in kwargs. The first thing it does is test to see if the key you just selected from kwargs is in kwargs. This test is always true. IIUC, the reason you're going through these contortions is that the argument list is long and repeated in a number of different places. So you're going to declare expected_form1_kwargs in one place and use it repeatedly. Presumably, you can also bundle the set/check code up in a function that you pass kwargs to as well. Have you thought about generating the more readable form from code you write? One of the most powerful tools available to programmers is code that writes code. This seems to be the perfect case for such a tool. You could, for instance, run your code through m4 to generate the Python that actually gets run. A trivial script that looks for ^def and then replaced **kwargs with your list could serve as a custom preprocessor. To be particulary perverse, you could try using a Cheetah template to generate your code - I've not tried generating Python with it, but it creates Makefiles quite nicely. mike -- Mike Meyer [EMAIL PROTECTED] http://www.mired.org/home/mwm/ Independent WWW/Perforce/FreeBSD/Unix consultant, email for more information. -- http://mail.python.org/mailman/listinfo/python-list
Re: Controlling output using print with format string
Paul Watson [EMAIL PROTECTED] writes: It is clear that just using 'print' with variable names is relatively uncontrollable. However, I thought that using a format string would reign the problem in and give the desired output. Must I resort to sys.stdout.write() to control output? No. You can control the output of print to whatever degree you want - just convert the printed objects to strings by hand before printing them. $ python Python 2.4.1 (#1, Jul 19 2005, 14:16:43) [GCC 4.0.0 20050519 (Red Hat 4.0.0-8)] on linux2 Type help, copyright, credits or license for more information. s = 'now is the time' for c in s: ... print c, ... n o w i s t h e t i m e for c in s: ... print %c % (c), ... n o w i s t h e t i m e for c in s: ... print %1c % (c), ... n o w i s t h e t i m e On the other hand, you can't keep print from putting a space between all the objects it prints. So you have to convert all the objects into a single string before printing that string. mike -- Mike Meyer [EMAIL PROTECTED] http://www.mired.org/home/mwm/ Independent WWW/Perforce/FreeBSD/Unix consultant, email for more information. -- http://mail.python.org/mailman/listinfo/python-list
Re: need start point for getting html info from web
[EMAIL PROTECTED] writes: i have a small app that i am going to need to get information from a few tables on different websites. i have looked at urllib and httplib. the sites i need to get data from mostly have this data in tables. So that, i think would make it easier. Anyone suggest a good starting point for me to find out how to do this, or know of a link to a good how-to? Don't have a link to a howto. But you're halfway there. urllib (and urllib2) will get HTML text from the websites. Pulling data from it sort of depends on the nature of the HTML. If it's well-structured XHTML, you can use your favorite xml library. if it's well structured HTML, you can try htmllib, but it's pretty primitive. If it's not well-structured, you can use BeautifulSoup. I've used it to pull data from tables. The problem with any of this is that your code really depends on the structure - or lack thereof - of the HTML you're scraping. If they change it, your code breaks. mike -- Mike Meyer [EMAIL PROTECTED] http://www.mired.org/home/mwm/ Independent WWW/Perforce/FreeBSD/Unix consultant, email for more information. -- http://mail.python.org/mailman/listinfo/python-list
Re: Expanding Python as a macro language
[EMAIL PROTECTED] (Alex Martelli) writes: ... But the problem is that in Linux you can't even send a keystroke to a running GUI application! Actually, if the app is running under X11 you may try to fake out a keystroke event (with low level calls, but ctypes might let you use it from Python). Of course, the app WILL be told that the keystroke is fake, through a special flag if it cares to check for it, for security reasons; but if the app doesn't specifically defend itself in this way. I'm pretty sure that python-xlib can do this without having to go to low level calls. mike -- Mike Meyer [EMAIL PROTECTED] http://www.mired.org/home/mwm/ Independent WWW/Perforce/FreeBSD/Unix consultant, email for more information. -- http://mail.python.org/mailman/listinfo/python-list
Re: Automatic binding of **kwargs to variables
[EMAIL PROTECTED] [EMAIL PROTECTED] writes:
Mike Meyer wrote:
[snip]
for name, value in kwargs.items():
if name in ('a', 'list', 'of', 'valid', 'keywords'):
exec %s = %s % (name, value)
else:
raise ValueError, Unrecognized keyword + name
Others will probably tell you that you really shouldn't be using exec.
What about using setattr?
for name, value in kwargs.items():
if name in ('a', 'list', 'of', 'valid', 'keywords'):
setattr(self, name, value)
else:
raise ValueError, Unrecognized keyword + name
You clipped my description of what's wrong with setattr: it doesn't
bind the names in the local namespace, it binds them to an
object. This may be acceptable, but wasn't what the OP asked for.
I'd probably turn the list of valid keywords into another dictionary to
make it easy to specify default values for all the parameters as well.
If you're going to do that, why not just specify them explicitly in
the function definition instead of using **kwargs? That takes care of
everything - binding, checking, and providing a default value - in one
swoop.
mike
--
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Re: Scanning a file
Paul Watson [EMAIL PROTECTED] writes: Mike Meyer [EMAIL PROTECTED] wrote in message news:[EMAIL PROTECTED] Paul Watson [EMAIL PROTECTED] writes: ... Did you do timings on it vs. mmap? Having to copy the data multiple times to deal with the overlap - thanks to strings being immutable - would seem to be a lose, and makes me wonder how it could be faster than mmap in general. The only thing copied is a string one byte less than the search string for each block. Um - you removed the code, but I could have *sworn* that it did something like: buf = buf[testlen:] + f.read(bufsize - testlen) which should cause the the creation of three strings: the last few bytes of the old buffer, a new bufferfull from the read, then the sum of those two - created by copying the first two into a new string. So you wind up copying all the data. Which, as you showed, doesn't take nearly as much time as using mmap. Thanks, mike -- Mike Meyer [EMAIL PROTECTED] http://www.mired.org/home/mwm/ Independent WWW/Perforce/FreeBSD/Unix consultant, email for more information. -- http://mail.python.org/mailman/listinfo/python-list
Re: Recursive generators and backtracking search
Talin [EMAIL PROTECTED] writes: As an alternative, I'd like to present the following implementation. If you compare this one with the one in lib/test/test_generator.py you will agree (I hope) that by using recursive generators to implement backtracking, the resulting code is a little more straightforward and intuitive: I'd propose one change to that... def qsearch( qarray = () ): for q in range( 0, bsize ):# Try each position if not threaten( qarray, q ): # If not threatened pos = qarray + ( q, ); # Append to the pos array if len( pos ) = bsize:# Are we done? yield pos # Yield the answer else:# recursively call new generator for pos in qsearch( pos ): yield pos Um - do you really want to reuse the variable pos here? Yeah, it works, but this strikes me as very confusing. I'm not sure that it might not be implementation dependent. mike -- Mike Meyer [EMAIL PROTECTED] http://www.mired.org/home/mwm/ Independent WWW/Perforce/FreeBSD/Unix consultant, email for more information. -- http://mail.python.org/mailman/listinfo/python-list
Re: Expanding Python as a macro language
[EMAIL PROTECTED] writes: My answer is the same as that given to Michael about low level programming. But I must thank anyway Alex for giving informations to such a level (I didn't know that under Linux there was such a level of sophistication with the possibility for an application to discover fake keystrokes...). If this fake keystroke is used to fire an event (like pressing a button), the fake flag is propagated to the action taken by the button? The action is internal to the application, so whether or not it propogates the fake flag is up to the application. In between the X event and the action is the GUI library, which may also choose to not propogate the flag. For the other Alex observations (about Mac OsX and my examples of automation centered on web automation) I have a PC, and the fact that Python is very good at dealing with the web, doesn't help too much in this case... In any case a macro language like AutoIt is a general purpose application. At last I must thank Mike Meyer for his suggestion to use python-xlib to avoid low level programming... Just to clarify - python-xlib will let you avoid the need for C functions to do things like send X events. In that sense, it helps you avoid low-level programming. On the other hand, you're still sending X events, so in *that* sense, you're not avoiding low-level programming. In general, application scripting facilities are one thing that Unix hasn't dealt with well. Windows and OS X both do better (but neither do as well later versions of AmigaDOS). Whereas those systems come with a (or a selection) mechanism that applications can use to allow macro programming, Unix doesn't, so each application is left up to it's own devices. The most popular solution is to embed a custom language for scripting - which is where something like Python comes in. Some of them now export APIs that can be hooked up to a variety of languages. IIRC, Gnome has embraced CORBA as an interface for such, but it didn't seem well supported the last time I looked. The bottom line is that when it comes to scripting applications on Unix, your solution is going to be tailored to the application. The Unix variant with the best system-provided scripting facility is probably Plan 9. Some Linux variants are moving in that direction, but I don't know of any Linux applications that provide support for it. mike -- Mike Meyer [EMAIL PROTECTED] http://www.mired.org/home/mwm/ Independent WWW/Perforce/FreeBSD/Unix consultant, email for more information. -- http://mail.python.org/mailman/listinfo/python-list
Re: Scanning a file
Andrew McCarthy [EMAIL PROTECTED] writes: On 2005-10-28, [EMAIL PROTECTED] [EMAIL PROTECTED] wrote: I'm now down to: f = open(filename, rb) s = f.read() sub = \x00\x00\x01\x00 count = s.count(sub) print count Which is quite fast. The only problems is that the file might be huge. I really have no need for reading the entire file into a string as I am doing here. All I want is to count occurences this substring. Can I somehow count occurences in a file without reading it into a string first? Yes - use memory mapping (the mmap module). An mmap object is like a cross between a file and a string, but the data is only read into RAM when, and for as long as, necessary. An mmap object doesn't have a count() method, but you can just use find() in a while loop instead. Except if you can't read the file into memory because it's to large, there's a pretty good chance you won't be able to mmap it either. To deal with huge files, the only option is to read the file in in chunks, count the occurences in each chunk, and then do some fiddling to deal with the pattern landing on a boundary. mike -- Mike Meyer [EMAIL PROTECTED] http://www.mired.org/home/mwm/ Independent WWW/Perforce/FreeBSD/Unix consultant, email for more information. -- http://mail.python.org/mailman/listinfo/python-list
Re: Typing tutor help script needed, please
Throw [EMAIL PROTECTED] writes: G'day everyone! I would like to design typing tutor exercises for Afrikaans (and other languages possibly). This is for a GPL project. For this, I need a script that can extract words from a long list of words, based on which letters those words contain, and write then write output to a file. Does anyone know of an existing script for this, or can anyone write me one, please? This sounds nearly trivial in Python. More specifics would help. Preferably I must be able to extract words which contain only certain letters (they need not contain all of those letters, but they may not contain any other letters). It would be nice if I can also extract words which do not contain certain letters. Again, this sounds nearly trivial in Python. For instance. to get a list of all words that don't contain 'a', you'd do something like: f = open(textfile) words = f.read().split() f.close() selected = [word for word in words if 'a' not in word] and then selected has the list of words that don't have an 'a' in them. Tweaking the test the other way - to select words with an 'a', remove the 'not'. You can combine the tests with 'and' and 'or'. But without a UI, that's pretty much useless - and you haven't said what you want the UI to be. mike -- Mike Meyer [EMAIL PROTECTED] http://www.mired.org/home/mwm/ Independent WWW/Perforce/FreeBSD/Unix consultant, email for more information. -- http://mail.python.org/mailman/listinfo/python-list
Re: Newbie question: string replace
[EMAIL PROTECTED] [EMAIL PROTECTED] writes: Now it works: rex = re.compile(r'(^.*username *=[^]*)([^]*)(.*$)') for line in fileinput.input(FILE, inplace=1): m = rex.match(line) if m is not None: line = %s%s%s\n % (m.group(1), new_name, m.group(3)) print line But there is an extra line break after each line in FILE. Why is that? Because print prints a newline after all the values you pass it. I tried to line = %s%s%s % (m.group(1), new_name, m.group(3)) but it turns out there are two extra line breaks after each line... It's not clear what you mean by this. I would have expected this change to solve the problem. Where do you get two extra newlines? mike -- Mike Meyer [EMAIL PROTECTED] http://www.mired.org/home/mwm/ Independent WWW/Perforce/FreeBSD/Unix consultant, email for more information. -- http://mail.python.org/mailman/listinfo/python-list
Re: Microsoft Hatred FAQ
David Schwartz [EMAIL PROTECTED] writes: Mike Meyer [EMAIL PROTECTED] wrote in message news:[EMAIL PROTECTED] The quote about the mafia doesn't compare MS's actions to actual use of force. I'm sorry, that's just absurd. I won't speculate on what motivates you to engage in such crazy distortion. Of course the quote about the Mafia compares MS's actions to actual use of force. Maybe true, maybe not - but it doesn't matter. The point is that you respond to *every* comparison of MS with other criminals as a comparison to criminals with guns, and then refuse to discuss the issue, with utter disregard as to what the other person said. That you might be right in one case is irrelevant - we're talking about a pattern of behavior. If MS had been found guilty of abuse of monopoly power in one instance, few people would care. People do make mistakes. That they have been found guilty of such abuse repeatedly, on multiple continents, and were recently caught doing it yet again - that's what makes them criminals. It's the pattern of behavior that matters, not the single instances. I'm still waiting for you to come up with an explanation for the pattern of your behavior other than that you're taking orders from MS. But I expect yout to deny that it exists. mike -- Mike Meyer [EMAIL PROTECTED] http://www.mired.org/home/mwm/ Independent WWW/Perforce/FreeBSD/Unix consultant, email for more information. -- http://mail.python.org/mailman/listinfo/python-list
Re: Automatic binding of **kwargs to variables
[EMAIL PROTECTED] [EMAIL PROTECTED] writes:
I have a very long list of parameters coming from a web form to my
method foo(self, **kwargs)
I would like to avoid manually binding the variables to the values
coming through the **kwargs dictionary, just to keep the code cleaner,
I'd like to bind them automatically
I was adviced against doing it by adding stuff to locals such as:
locals()[x] = 5
since the Python Docs say:
Warning: The contents of this dictionary should not be modified;
changes may not affect the values of local variables used by the
interpreter.
Is there a way to do this? Maybe object.__setattr__() or something that
involves metaclasses?
.__setattr__() will modify the instance variables, not the local
variables.
As I might go touching something that I shouldn't (like locals()) I'd
like some advice from you before deciding which way to go.
Reference the keyword arguments through the dictionary. Looking up
values by name is what dictionaries are for. Trying to move the names
from a dictionary into the local (or global) namespace is usually a
bad idea. If you don't know all the names in advance, you risk
collisions between the items in the dictionary and the legitimate
inhabitants of the namespace. If you do know all the names in advance,
you need to make sure the keys in the dictionary are in the list of
values you expect, so you need an explicit list.
That said, the most straightforward way to do this that I can think of
is with exec:
for name, value in kwargs.items():
if name in ('a', 'list', 'of', 'valid', 'keywords'):
exec %s = %s % (name, value)
else:
raise ValueError, Unrecognized keyword + name
Others will probably tell you that you really shouldn't be using exec.
mike
--
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Re: Microsoft Hatred FAQ
David Schwartz [EMAIL PROTECTED] writes: Mike Meyer [EMAIL PROTECTED] wrote in message news:[EMAIL PROTECTED] David Schwartz [EMAIL PROTECTED] writes: Mike Meyer [EMAIL PROTECTED] wrote in message news:[EMAIL PROTECTED] Maybe true, maybe not - but it doesn't matter. The point is that you respond to *every* comparison of MS with other criminals as a comparison to criminals with guns, and then refuse to discuss the issue, with utter disregard as to what the other person said. That you might be right in one case is irrelevant - we're talking about a pattern of behavior. That is not true. I make a serious distinction between crimes that involve the use of force and crimes that don't. Microsoft was convicted of crimes that do *not* involve use of force. I am trying very hard to make sure that distinction is preserved. Except you treat *every* mention of any crime other than abuse of monopoly power as a crime that involves the use of force - whether it does or not. In the example I quoted, you did it with theft - without reference to how the theft happened. There are lots of forms of theft that don't involve use of force - abuse of monopoly power is one of them, but so is embezzlement. Yet you accused me of equating arguments with guns. I'm still waiting for you to come up with an explanation for the pattern of your behavior other than that you're taking orders from MS. But I expect yout to deny that it exists. The pattern of my behavior is that it is vital to me to preserve the distinction between force and non-force. If it that vital, then you need to make the distinction yourself, and quit treating *any* crime not committed by MS as if it involved the use of force. Guns and arguments represent two fundamentally different categories of human behavior. And I reject the moral claim that it is okay to respond to arguments with guns. Oh, we know you reject it. You never miss an opportunity to say so - even if it's not at all relevant. As predicted, you denied the truth of what I said, then provided an excuse for a behavior that you don't follow. So we're still waiting for an explanation for your actual behavior other than your being a shill for MS. Microsoft's behavior consisted of arguments, that is, did not involve force, the threat of force, fraud, or the threat of fraud. This is perhaps the most vital distinction that there is. Wrong. Either your definition of force is to narrow, or you're wrong that it's the distinction is even vaguely vital. If I convince everyone who might make food available to you not to do so - for example, by paying them more than their interaction with you is worth to them, I can starve you to death. I'd say I've used force against you - an economic force. This is the kind of force that MS wields illegally. I'm willing to admit this isn't a usual definition of force, and won't argue if you want to say that it isn't force. But in that case, the fact that I didn't use force against you is irrelevant to you - you're just as dead. mike -- Mike Meyer [EMAIL PROTECTED] http://www.mired.org/home/mwm/ Independent WWW/Perforce/FreeBSD/Unix consultant, email for more information. -- http://mail.python.org/mailman/listinfo/python-list
Re: Scanning a file
Paul Watson [EMAIL PROTECTED] writes: Here is a better one that counts, and not just detects, the substring. This is -much- faster than using mmap; especially for a large file that may cause paging to start. Using mmap can be -very- slow. #!/usr/bin/env python import sys fn = 't2.dat' ss = '\x00\x00\x01\x00' be = len(ss) - 1# length of overlap to check blocksize = 64 * 1024# need to ensure that blocksize overlap fp = open(fn, 'rb') b = fp.read(blocksize) count = 0 while len(b) be: count += b.count(ss) b = b[-be:] + fp.read(blocksize) fp.close() print count sys.exit(0) Did you do timings on it vs. mmap? Having to copy the data multiple times to deal with the overlap - thanks to strings being immutable - would seem to be a lose, and makes me wonder how it could be faster than mmap in general. Thanks, mike -- Mike Meyer [EMAIL PROTECTED] http://www.mired.org/home/mwm/ Independent WWW/Perforce/FreeBSD/Unix consultant, email for more information. -- http://mail.python.org/mailman/listinfo/python-list
Re: how do i run another script from my python script
Daniel Schüle [EMAIL PROTECTED] writes: Steve already answeared to your question, regaring PHP script if this would be python script, you could run it by import'ing it That's not very pythonic. Better is to provide a function in the script to run it (say run), then run that in the script iff it's the script is being executed: if __name__ == '__main__': run() Then to use it from another script, you'd do something like: import myscript myscript.run() or maybe using threading Launching new threads as part of the import process is *dangerous*. There are some nasty bugs lurking there that cause things like your import never finishing. If you need to start a thread in a module, the approach outlined above avoids those bugs. mike -- Mike Meyer [EMAIL PROTECTED] http://www.mired.org/home/mwm/ Independent WWW/Perforce/FreeBSD/Unix consultant, email for more information. -- http://mail.python.org/mailman/listinfo/python-list
Re: How to replace all None values with the string Null in a dictionary
dcrespo [EMAIL PROTECTED] writes: Hi all, How can I replace all None values with the string 'Null' in a dictionary? Iterate over everything in the dictionary: for key, item in mydict.items(): if item is None: mydict[key] = 'Null' mike -- Mike Meyer [EMAIL PROTECTED] http://www.mired.org/home/mwm/ Independent WWW/Perforce/FreeBSD/Unix consultant, email for more information. -- http://mail.python.org/mailman/listinfo/python-list
Re: Microsoft Hatred FAQ
Paul Rubin http://[EMAIL PROTECTED] writes: Sorry to be pedantic, but I think it's an important point that no court ever found that Microsoft illegally acquired a monopoly. So to characterize the monopoly itself as illegal is simply erroneous. Who is paying you to tell these ridiculous crap? The monopoly is illegal if maintained by anticompetitive means regardless of how it was acquired. From http://cyber.law.harvard.edu/msdoj/conclusions-l.html: Section 2 of the Sherman Act declares that it is unlawful for a person or firm to monopolize . . . any part of the trade or commerce among the several States, or with foreign nations . . . . 15 U.S.C. § 2. This language operates to limit the means by which a firm may lawfully either acquire or perpetuate monopoly power. Specifically, a firm violates sec. 2 if it attains or preserves monopoly power through anticompetitive acts. The threshold element of a sec 2 monopolization offense being the possession of monopoly power in the relevant market... Which means that the successful exercise of monopoly power is sufficient to demonstrate the existence of a monopoly. A claim that David Schwartz has never bothered to answer. David Schwartz, I have a direct question for you: are you on Microsoft's payroll? I've noticed something strange that makes me wonder the same thing. Everytime someone compares MS's behavior with that of any other criminals, he responds about MS's activity being equated to that of criminals with guns, and refuses to discuss the issue. Ironically, while no one else has so much as compared MS to criminals with guns - after all, they're white collar criminals - David Schwartz called the DOJ official who were investigating MS criminals with guns pointed out [MS officers] heads. It seems like he's trying to avoid (further) tarnishing MS's reputation by avoiding having MS associated with other criminals. You have to wonder what could caause that kinnd of behavior. mike -- Mike Meyer [EMAIL PROTECTED] http://www.mired.org/home/mwm/ Independent WWW/Perforce/FreeBSD/Unix consultant, email for more information. -- http://mail.python.org/mailman/listinfo/python-list
Re: Microsoft Hatred FAQ
David Schwartz [EMAIL PROTECTED] writes: Mike Meyer [EMAIL PROTECTED] wrote in message news:[EMAIL PROTECTED] I've noticed something strange that makes me wonder the same thing. Everytime someone compares MS's behavior with that of any other criminals, he responds about MS's activity being equated to that of criminals with guns, and refuses to discuss the issue. Ironically, while no one else has so much as compared MS to criminals with guns - after all, they're white collar criminals - David Schwartz called the DOJ official who were investigating MS criminals with guns pointed out [MS officers] heads. I can't understand why you would post an outright lie like this. I, on the other hand, understand why you accuse me of lying. You don't have an answer to the claim, so you call the claim false. SOP for you. Ironically, while no one else has so much as compared MS to criminals with guns. I defy you to find *one* place where I complain that MS behavior is equated to the actual use of force where that is not in fact done in precisely the thread I'm replying to. The first one is at: http://groups.google.com/group/comp.lang.python/msg/8422f41c9fe137b0?dmode=sourcehl=en The original comment was: No, they didn't ask for more than Windows were worth. They tilted the playing field against MS competitors by causing consumers to pay MS money for products they didn't receive. In most countries, taking money from unwilling victims without giving them anything in exchange is called theft. Note that no mention is made of guns or force - just a definition of theft. Unless you're so narrowminded that nothing short of pointing a gun at someone and demanding money from them is stealing from them, there is no way that this can be equated to the actual use of force. And if you do believe that definition of stealing, I'll do your bookkeeping for free - and I won't steal from you. Your reply: It is not theft if you can simply say no to the deal and all that happens is that you don't get the product. Your argument is preposterous. If you accept arguments that equate guns with arguments, the next step is that using a gun is a rational response to an argument one doesn't like. Oh wait, you're already there. Wherein you accuse me of equating MS's actions with using guns, which is *exactly* what I said you do. There are lots more examples of you doing this kind of thing. Like I said, everytime someone compares MS's behavior with some less controversial criminal behavior, you act like they accused MS of holding people up at gunpoint. mike -- Mike Meyer [EMAIL PROTECTED] http://www.mired.org/home/mwm/ Independent WWW/Perforce/FreeBSD/Unix consultant, email for more information. -- http://mail.python.org/mailman/listinfo/python-list
Re: specify arbitrary library directory directly in code?
[EMAIL PROTECTED] writes: ### Initial Findings After searching around a bit, it appears that python does not have a built-in mechanism for specifying arbitrary directories as the first place to look for module code. There are options that allow one to specify alternate directories, but all these options require changes to environment variables, or changes (or additions) to the files in the standard package directories. But if you define 'built-in mechanism' meaning a change that only requires modifying the code in 'faa_script.py' ... then there is no 'built-in mechanism'. ### Question Are the initial findings correct? If not, can you specify the code (or the link to the documentation) that specifies how to do what I am trying to do? If the initial findings are correct, are there any alternative workarounds to allow faa_script.py to automatically discover module code in specific sibling directories? No, the findings aren't correct. You can manipulate the search path directly. import sys sys.path.insert(0, /directory/to/search) will cause future imports to search /directory/to/search before all other directories. Likewise, sys.append(/directory/to/search) will search it after other directories. Docs here: http://www.python.org/doc/2.2.3/tut/node8.html#SECTION00820 mike -- Mike Meyer [EMAIL PROTECTED] http://www.mired.org/home/mwm/ Independent WWW/Perforce/FreeBSD/Unix consultant, email for more information. -- http://mail.python.org/mailman/listinfo/python-list
Re: Microsoft Hatred FAQ
David Schwartz [EMAIL PROTECTED] writes: Mike Meyer [EMAIL PROTECTED] wrote in message news:[EMAIL PROTECTED] Ironically, while no one else has so much as compared MS to criminals with guns. I defy you to find *one* place where I complain that MS behavior is equated to the actual use of force where that is not in fact done in precisely the thread I'm replying to. The first one is at: http://groups.google.com/group/comp.lang.python/msg/8422f41c9fe137b0?dmode=sourcehl=en The original comment was: No, they didn't ask for more than Windows were worth. They tilted the playing field against MS competitors by causing consumers to pay MS money for products they didn't receive. In most countries, taking money from unwilling victims without giving them anything in exchange is called theft. Note that no mention is made of guns or force - just a definition of theft. Unless you're so narrowminded that nothing short of pointing a gun at someone and demanding money from them is stealing from them, there is no way that this can be equated to the actual use of force. And if you do believe that definition of stealing, I'll do your bookkeeping for free - and I won't steal from you. Your reply: It is not theft if you can simply say no to the deal and all that happens is that you don't get the product. Your argument is preposterous. If you accept arguments that equate guns with arguments, the next step is that using a gun is a rational response to an argument one doesn't like. Oh wait, you're already there. Wherein you accuse me of equating MS's actions with using guns, which is *exactly* what I said you do. This thread is large and complex, and I can't always know exactly what's a reply to what reply to what. So what's said in what part of a thread may carry over to another part of that same thread. So follow the link and read it. I quoted the comment and reply directly to make life easier on the readers. I quoted them exactly in context. That you try and deny they illustrate you doing exactly what I said you do is only to be expected. There are lots more examples of you doing this kind of thing. Like I said, everytime someone compares MS's behavior with some less controversial criminal behavior, you act like they accused MS of holding people up at gunpoint. They are. Read the quotes. Here they are again: So what? That doesn't change the essential truth of my statement - that you react to *every* comparison of MS's activities with less controversial criminal activity with the You're comparing them to criminals with guns. I won't discuss that. It really does make me think that you're more interested in protecting MS's reputation than in any discussinon. Unless you're so narrowminded that nothing short of pointing a gun at someone and demanding money from them is stealing from them, there is no way that this can be equated to the actual use of force. And if you do believe that definition of stealing, I'll do your bookkeeping for free - and I won't steal from you. You are seriously saying that people in this thread have not consistently described Microsoft's actions as analogous to an actual use of force? Have you read any of the thread? Do I need to dig out more quotes? Yes, I've read the thread. It's full of you creating straw men, calling those who disagree with you liars, calling the government crooks, and the like. I'd be interested in seeing *one* quote that compare MS's actions to the actual use of force. And I want what I gave you - the link to the google groups page the quote came from, and enough context to find it. The quote about the mafia doesn't compare MS's actions to actual use of force. It compares MS to people who are willing to use force to get their ends. But there is no actual use of force. These are all from early in the thread, long before the posts you are complaining about: The choice was go along with MS arm twisting or go out of business. No, this wasn't long before the post I quoted; it occured well after it. And while this really does refer to the actual use of force, anyone even vaguely familiar with common english usage will recognize the phrase arm twisting as an idiomatic usage for a being extremely persuasive, with no actual use of force taking place. If that's the best you can do, you really haven't got an argument. To my way of thinking what MS did was similar to a the only magasine wholesaler in town telling retailers it had to sell kiddie porn under the table or pay full retail for all magazines. No actual use of force in this one, either. This is a *very* apt comparison. The only real difference between this and what MS did is that it replaces something mildly objectionable - charging people for something they aren't getting - with something very objectionable - selling kiddie porn. However, you may be right that some of my replies to you may not have been justified as responses to just
Re: a Haskell a Day
Erik Max Francis [EMAIL PROTECTED] writes: Xah Lee wrote: This is my learning notes on Haskell. I call it a-Haskell-a-day. Interesting. Xah Lee's orginals don't show up in the Python newsgroup. No big loss. In any case, please help google find Xah Lee under the proper search terms. Add a link to his website with the anchor stupider than spam. A typical usage might be: And pointing out that some people are a href=http://xahlee.org/;stupider than spam/a. Thanks, mike -- Mike Meyer [EMAIL PROTECTED] http://www.mired.org/home/mwm/ Independent WWW/Perforce/FreeBSD/Unix consultant, email for more information. -- http://mail.python.org/mailman/listinfo/python-list
Re: Double replace or single re.sub?
Iain King [EMAIL PROTECTED] writes:
I have some code that converts html into xhtml. For example, convert
all i tags into em. Right now I need to do to string.replace calls
for every tag:
html = html.replace('i','em')
html = html.replace('/i','/em')
I can change this to a single call to re.sub:
html = re.sub('([/]*)i', r'\1em', html)
Would this be a quicker/better way of doing it?
Maybe. You could measure it and see. But neither will work in the face
of attributes or whitespace in the tag.
If you're going to parse [X]HTML, you really should use tools that are
designed for the job. If you have well-formed HTML, you can use the
htmllib parser in the standard library. If you have the usual crap one
finds on the web, I recommend BeautifulSoup.
mike
--
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Re: Set an environment variable
Jorgen Grahn [EMAIL PROTECTED] writes: On Wed, 26 Oct 2005 07:42:19 -0700, Alex Martelli [EMAIL PROTECTED] wrote: Grant Edwards [EMAIL PROTECTED] wrote: On 2005-10-24, Eric Brunel [EMAIL PROTECTED] wrote: The only think you can export an environment variable to is a child process Well, you know that, and I know that too. From my experience, many people don't... True. Using Unix for 20+ years probably warps one's perception of what's obvious and what isn't. This specific issue is identical in Windows, isn't it? I do not know any OS which does have the concept of environment variable yet lets such variables be ``exported'' to anything but a child process. AmigaDOS, if I recall correctly. Its ENV: drive/namespace is global, and that's its closest thing to Unix environment variables. AmigaDOS had both global environment variables (using the ENV: device) and local environment variables, that worked like the Unix version. You manipulated them in a similar way in the shell, and they had a similar API for programmers: one call with a flag to indicate which you wanted. The ENV: device was an implementation detail that let you save/restore the state of the global environment with file commands. The posix calls checked the local then global variables. Of course, this is now 10+ year old memory, and I may not RC. mike -- Mike Meyer [EMAIL PROTECTED] http://www.mired.org/home/mwm/ Independent WWW/Perforce/FreeBSD/Unix consultant, email for more information. -- http://mail.python.org/mailman/listinfo/python-list
Re: Read/Write from/to a process
Dennis Lee Bieber [EMAIL PROTECTED] writes: Followed by the Amiga... The Amiga IPC used message ports (linked lists owned by the creating process to which, if public [named], other processes could send message packets). The Amiga port of REXX made use of message ports as its native IPC... address SOME_APPLICATION would redirect all non-REXX statements to the message port named SOME_APPLICATION; the default being address COMMAND -- a shell interpreter. Then, any non-REXX statement would be processed by the shell interpreter -- and the easiest way to force a non-REXX statement was to put a quote mark around it (or the first word of it) delete my_file_var would translate my_file_var to whatever had been assigned to it earlier, and pass a delete command to the shell. address ED would now route such statements to the ed editor These things weren't unique to the Amiga port of Rexx. Rexx on VM/CMS did all these things. Tying them to the native IPC mechanism as a brilliant move. Add in the shared library for supporting Rexx so that adding Rexx support to an application (or to a language!) was trivial, and Rexx the end result was that Rexx was used far more heavily on the Amiga than on VM/CMS. The downside was that variables had a default value of their name in upper case, and any statement that wasn't recognized evaluated as a string expresion and then fed to the current command processor. So that the quote marks weren't needed - if you hadn't assigned a value to the variable delete, then you could just do delete my_file_var and it would do the right thing. Of course, almost anything you typed like that was valid, creating interesting bugs. I made it a habit to keep 0 and 1 commands around that just logged errors, as those would catch such things. mike -- Mike Meyer [EMAIL PROTECTED] http://www.mired.org/home/mwm/ Independent WWW/Perforce/FreeBSD/Unix consultant, email for more information. -- http://mail.python.org/mailman/listinfo/python-list
Re: security
Mattia Adami [EMAIL PROTECTED] writes: Hi to all. I'm intristing in write a plugin for browsers that can execute python code. I know the main problem is security. Many thread were opened about this in the ng. I would know if fork python rewriting some library could avoid problems. I.e. one problem is the possibility to access files. If I rewrite the open() function so that raises exception if the program try to access a file out of a defined directory. I'm sure not a security expert, so please be patient if my question is stupid. People who *are* security experts have looked into modifying Python to make it secure, and given up on the project as unrealistic. Generally, taking an existing project that wasn't designed with security in mind and making it secure is hard. Not impossible, but not easy. You might consider using Jython and jythonc to produce objects to run in the JVM. Not only was that designed with security in mind, but most browsers come with a JVM already installed. mike -- Mike Meyer [EMAIL PROTECTED] http://www.mired.org/home/mwm/ Independent WWW/Perforce/FreeBSD/Unix consultant, email for more information. -- http://mail.python.org/mailman/listinfo/python-list
Re: [OT] Re: output from external commands
Terry Hancock [EMAIL PROTECTED] writes: I think Mr. Lundh's point was only that the output from glob.glob is already guaranteed to be strings, so using either '%s'%f or str(f) is superfluous. Just for the record - this was why I asked what the point was in the first place. mike -- Mike Meyer [EMAIL PROTECTED] http://www.mired.org/home/mwm/ Independent WWW/Perforce/FreeBSD/Unix consultant, email for more information. -- http://mail.python.org/mailman/listinfo/python-list
Re: Newbie question: string replace
[EMAIL PROTECTED] [EMAIL PROTECTED] writes: So how to overwrite the config file directly in script.py instead of running script.py with two params? Don't overwrite the file directly. Save a copy, then rename it. That way, you don't replace the new version until you know the old version is safely written to disk, thus avoid accidently losing the data in the file. def modfile(filein, mod): fileout = filein + ' temp' fin = open(filein, 'r') fout = open(fileout, 'w') fout.write(mod(fin.read())) fin.close() fout.close() os.unlink(filein) os.rename(fileout, filein) The truly paranoid will replace os.unlink(filein) with os.rename(filein, filein + '.back'). mike -- Mike Meyer [EMAIL PROTECTED] http://www.mired.org/home/mwm/ Independent WWW/Perforce/FreeBSD/Unix consultant, email for more information. -- http://mail.python.org/mailman/listinfo/python-list
Re: Microsoft Hatred FAQ
Not Bill Gates [EMAIL PROTECTED] writes: [EMAIL PROTECTED] wrote... On Tue, 25 Oct 2005 15:35:47 +, Not Bill Gates wrote: Heck, I dunno. Like you, I don't even really care all that much. You don't care that innovation in desktop software has been crippled by the actions of the monopoly player Microsoft? You need to first prove innovation in desktop software has been crippled, don't you? MS took desktop software through pretty much the same sequence of offerings that the mainframe and minicomputer software industry had been throgh: flat file systems and single-tasking OS's in a command line environment, adding nested file systems, adding TSRs, adding a windowing environment, adding true multitasking and finally multiprocessor systems. This took them what - 20+ years? While MS was innovating by giving us directories, others who had learned the lessons from mainframe and minicomputer systems were offering us desktop systems with all those features - and an office suite that ran in the windowing systems - for a fraction of the price of anything that was capable of running MS-DOS. MS managed to kill off or drive into niche markets the companies who were actually doing innovative work on desktop systems, and it's taken the desktop software industry two decades to recover from that. I'll accept that as crippling until a better definition comes along. mike -- Mike Meyer [EMAIL PROTECTED] http://www.mired.org/home/mwm/ Independent WWW/Perforce/FreeBSD/Unix consultant, email for more information. -- http://mail.python.org/mailman/listinfo/python-list
Re: Top-quoting defined [was: namespace dictionaries ok?]
On Tuesday 25 October 2005 00:31, Duncan Booth wrote: P.S. James, *please* could you avoid top-quoting James Stroud [EMAIL PROTECTED] writes: I'm sorry if I can't find a dumb terminal for a VAX with which to read my email. Perhaps, if i could, I would understand your frustration a little better. You don't need a VAX. All it takes is trying to dethread a top-posted conversation. I've given up in frustration on more than one such venture. The only reason I'm making a point of this is that many people come to python from fields other than computer science or hacker-ology. Posting styles will vary considerably among these people, so deal with the deviants carefully. I belive Duncan did so. He asked you to please* avoid to top-posting. Their differences in styles, like mine, probably arise from the culture of their respective fields. Most, like me, may not even know what the heck you are talking about. Also, here is a well written synopsis of the arguments in favor of top-posting and they may even be strong enough to legitimize the practice: http://alpage.ath.cx/toppost/toppost.htm Well, if I could find a 300 baud modem, I might understand his objection to not top-posting (he really only has one). His comments about why people shouldn't complain about top-posting are full of suggestions that don't generally work on netnews and mail, though they may be valid elsewhere, and his suggestion about when to top-post leaves out the *very important* criteria that you don't expect to read any replies to your comment, and don't care if you make life difficult for those who have different expectations. He's right about inadequately-trimmed repklies, though. Not being on a 300 baud modem, I don't think they're as annoying as top-posting, but they are certainly something that we can do without. In light of these arguments, I hereby reserve the right to revert to top-posting if the compulsion overwhelms me. That's your right. Be aware that people will ignore, correct and/or complain about you doing so. mike -- Mike Meyer [EMAIL PROTECTED] http://www.mired.org/home/mwm/ Independent WWW/Perforce/FreeBSD/Unix consultant, email for more information. -- http://mail.python.org/mailman/listinfo/python-list
Re: Microsoft Hatred FAQ
Not Bill Gates [EMAIL PROTECTED] writes: [EMAIL PROTECTED] wrote... Not Bill Gates [EMAIL PROTECTED] writes: [EMAIL PROTECTED] wrote... On Tue, 25 Oct 2005 15:35:47 +, Not Bill Gates wrote: Heck, I dunno. Like you, I don't even really care all that much. You don't care that innovation in desktop software has been crippled by the actions of the monopoly player Microsoft? You need to first prove innovation in desktop software has been crippled, don't you? MS took desktop software through pretty much the same sequence of offerings that the mainframe and minicomputer software industry had been throgh: flat file systems and single-tasking OS's in a command line environment, adding nested file systems, adding TSRs, adding a windowing environment, adding true multitasking and finally multiprocessor systems. This took them what - 20+ years? shrug Being pissed off about how things could have been done better is a losing proposition. I'm not pissed off about it - I've got better things to do. You asked for prove that desktop software development was crippled by MS. I provided it. mike -- Mike Meyer [EMAIL PROTECTED] http://www.mired.org/home/mwm/ Independent WWW/Perforce/FreeBSD/Unix consultant, email for more information. -- http://mail.python.org/mailman/listinfo/python-list
Re: output from external commands
darren kirby [EMAIL PROTECTED] writes: If all you want is filenames this will work: import glob files = [%s % f for f in glob.glob(*)] What's the point of doing %s % f? How is this different from just file = [f for f in glob.glob(*)]? mike -- Mike Meyer [EMAIL PROTECTED] http://www.mired.org/home/mwm/ Independent WWW/Perforce/FreeBSD/Unix consultant, email for more information. -- http://mail.python.org/mailman/listinfo/python-list
Re: Importing at runtime
David Poundall [EMAIL PROTECTED] writes: I have several .py files in a directory that I would like to import at run time. Each file contains a state machine that requires to be run in its own thread. Imports happen at run time. Beware starting threads in the code run at import time in each module, though - there are some nasty bugs lurking there. Instead, start the threads in functions invoked from the main routine. The first problem I have is how can I import the code in all of the .py files without knowing the file names in advance. Can this be done ?? Yes. Use the __import__ builtin. mike -- Mike Meyer [EMAIL PROTECTED] http://www.mired.org/home/mwm/ Independent WWW/Perforce/FreeBSD/Unix consultant, email for more information. -- http://mail.python.org/mailman/listinfo/python-list
Re: Microsoft Hatred FAQ
entropy [EMAIL PROTECTED] writes: [EMAIL PROTECTED] wrote... [EMAIL PROTECTED] wrote... In comp.lang.perl.misc David Schwartz [EMAIL PROTECTED] wrote: Mike Meyer [EMAIL PROTECTED] wrote in message Sorry, but nobody but the government actually owns property. In most places, you can't make non-trivial changes to your property without permission from the government. They even charge you rent on your property, only they call it property tax. I see you are a totalitarianist or perhaps a communist. If you want to live in America and discuss things that are relevent to America, let me know. Why would you say that - Mike Meyer made a point to which you have obviously no answer. Or do you deny that his comments on this matter of property are true? Methinks David simply missed that Mike was being facetious. (Irony and facetiousness don't translate well into print, as Frank Zappa once noted.) Uh, you _were_ being facetious there, weren't you Mike? No, I wasn't. The statements I made are true: the government charges you taxes on your property, and in most places restricts the changes you can make to it and the things you can do in it. I used the words rent and ownership in an unconventional way to emphasize the point. The conventional usage of ownwership ignores these kinds of facts. So you can talk about your house even if you're renting it, or if the bank still owns most of the house. There are political groups that are unhappy with these facts, and like to point out the inconsistencies in the usage of the word ownership. See URL: http://www.huppi.com/kangaroo/L-propertyrights.htm and URL: http://magazine.14850.com/9307/politics.html for examples of this. David claimed that everyone had a right to do whatever they wanted with their property. This is simply false throughout most of the civilized world - zoning laws control what kinds of business you can run on your property, various laws designed to control the looks of the town dictate what you can do to the exterior or lawn, flood and earthquake laws state what kinds of structural changes you can make, and so on. I took the view of a political extremist to point out that he was wrong. David predictably used that to tar me as an extremist from the other end of the spectrum. mike -- Mike Meyer [EMAIL PROTECTED] http://www.mired.org/home/mwm/ Independent WWW/Perforce/FreeBSD/Unix consultant, email for more information. -- http://mail.python.org/mailman/listinfo/python-list
Re: Microsoft Hatred FAQ
David Schwartz [EMAIL PROTECTED] writes: Instead, you outline a class of actions and tag them all as illegal. That's why we have laws against assault and battery and unsafe driving. And laws against exercising monopoly power in an unfair manner. Interesting how you, again, equate a gun and an argument. It is very important to you to justify responding to arguments with guns. However, I reject that premise at its roots, not just in your application of it. Another straw man. I never mentioned the word gun at all, and none of the crimes I discussed require a gun. You apparently aren't interested in constructive intercourse on the question. You're just interesting in knocking down your own arguments. Personally, I'd rather not watch you masterbate. mike -- Mike Meyer [EMAIL PROTECTED] http://www.mired.org/home/mwm/ Independent WWW/Perforce/FreeBSD/Unix consultant, email for more information. -- http://mail.python.org/mailman/listinfo/python-list
Re: how to count and extract images
Joe [EMAIL PROTECTED] writes:
start = s.find('a href=somefile') + len('a
href=somefile')
stop = s.find('Save File/a/B',
start) fileName = s[start:stop]
and then construct the url with the filename to download the image
which works fine as cause every image has the Save File link and I can
count number of images easy the problem is when there is more than image I
try using while loop downlaod files, wirks fine for the first one but
always matches the same, how can count and thell the look to skip the fist
one if it has been downloaded and go to next one, and if next one is
downloaded go to next one, and so on.
To answer your question, use the first optional argument to find in both
invocations of find:
stop = 0
while end = 0:
start = s.find('a href=somefile', stop) + len('a href=somefile')
stop = s.find('Save File/a/B', start)
fileName = s[start:stop]
Now, to give you some advice: don't do this by hand, use an HTML
parsing library. The code above is incredibly fragile, and will break
on any number of minor variations in the input text. Using a real
parser not only avoids all those problems, it makes your code shorter.
I like BeautifulSoup:
soup = BeautifulSoup(s)
for anchor in soup.fetch('a'):
fileName = anchor['href']
to get all the hrefs. If you only want the ones that have Save File
in the link text, you'd do:
soup = BeautifulSoup(s)
for link in soup.fetchText('Save File'):
fileName = link.findParent('a')['href']
mike
--
Mike Meyer [EMAIL PROTECTED] http://www.mired.org/home/mwm/
Independent WWW/Perforce/FreeBSD/Unix consultant, email for more information.
--
http://mail.python.org/mailman/listinfo/python-list
Re: Syntax across languages
Tom Anderson [EMAIL PROTECTED] writes: On Sun, 23 Oct 2005, Fredrik Lundh wrote: [EMAIL PROTECTED] wrote: - ~== for approximate FP equality str(a) == str(b) This is taken from the AI 754 standard, i take it? :) Seriously, that's horrible. Fredrik, you are a bad man, and run a bad railway. However, looking at the page the OP cites, the only mention of that operator i can find is in Dylan, and in Dylan, it's nothing to do with approximate FP equality - it means 'not identical', which we can spell is not. What would approximate FP equality even mean? How approximate? Hopefully user defined. Rexx has a global control that lets you set the number of digits to be considered significant in doing an FP equality test. mike -- Mike Meyer [EMAIL PROTECTED] http://www.mired.org/home/mwm/ Independent WWW/Perforce/FreeBSD/Unix consultant, email for more information. -- http://mail.python.org/mailman/listinfo/python-list
Re: output from external commands
James Colannino [EMAIL PROTECTED] writes: Hey everyone. First off, I'm new to the list. I had had a little bit of experience with Perl before discovering Python. The more Python I learn, the more I love it :) I just have a quick question to ask. I know that this is probably a simple question, but I've been googling around, and partly because I'm not sure exactly what to search for, I've been unsuccessful at finding an answer. What I'd like to do is be able to take the output of an external command and assign it as an array of strings. So, for example, in Perl I could do something like: @files = `ls`; So I guess I'm looking for something similiar to the backticks in Perl. Forgive me if I've asked something that's a bit basic for this list. Any help would be greatly appreciated :) Thanks very much in advance. This is a scripting language feature. Python doesn't have direct support for it, any more than C++ does. To get that functionality, you want to use either the os.popen function, or - preferable, but only available in newer Pythons - the subprocess module. mike -- Mike Meyer [EMAIL PROTECTED] http://www.mired.org/home/mwm/ Independent WWW/Perforce/FreeBSD/Unix consultant, email for more information. -- http://mail.python.org/mailman/listinfo/python-list
Re: Syntax across languages
Dennis Lee Bieber [EMAIL PROTECTED] writes: On Sun, 23 Oct 2005 20:59:46 -0400, Mike Meyer [EMAIL PROTECTED] declaimed the following in comp.lang.python: Hopefully user defined. Rexx has a global control that lets you set the number of digits to be considered significant in doing an FP equality test. That's the good part about the REXX model... The bad part? It's based on the number of significant digits... Rather than a true epsilon. Depends on what you mean by a true epsilon. If you mean I want the two values to differ by at most 10^-5, then number of significant digits is a better option. If you mean I want the two values to differ by at most 1 part in 10^5, then number of significant digits is a slightly less flexible option. You really, *really* don't want to specify the acceptable difference as a fixed value. You want it to be relative to the size of objects being compared. The latter is what number of significant digits gives you. The downside is that you're restricted to values that are a power of 10, and can't specify things like I want the two values to differ by at most one part in 34,000 or some such oddity. On the up side, number of significant digits is (maybe was - been a long time since I did any serious number crunching) a common form for expressing the accuracy of a calculation. mike -- Mike Meyer [EMAIL PROTECTED] http://www.mired.org/home/mwm/ Independent WWW/Perforce/FreeBSD/Unix consultant, email for more information. -- http://mail.python.org/mailman/listinfo/python-list
Re: best way to replace first word in string?
Steven D'Aprano [EMAIL PROTECTED] writes: py def tester(n): ... s1 = ... s2 = %s * n ... bytes = tuple([chr(i % 256) for i in range(n)]) ... t1 = time.time() ... for i in range(n): ... s1 = s1 + chr(i % 256) ... t1 = time.time() - t1 ... t2 = time.time() ... s2 = s2 % bytes ... t2 = time.time() - t2 ... assert s1 == s2 ... print t1, t2 ... py py tester(x) 3.24212408066 0.01252317428 py tester(x) 2.58376598358 0.01238489151 py tester(x) 2.76262307167 0.01474809646 The string formatting is two orders of magnitude faster than the concatenation. The speed difference becomes even more obvious when you increase the number of strings being concatenated: The test isn't right - the addition test case includes the time to convert the number into a char, including taking a modulo. I couldn't resist adding the .join idiom to this test: def tester(n): ... l1 = [chr(i % 256) for i in range(n)] ... s1 = ... t1 = time.time() ... for c in l1: ... s1 += c ... t1 = time.time() - t1 ... s2 = '%s' * n ... l2 = tuple(chr(i % 256) for i in range(n)) ... t2 = time.time() ... s2 = s2 % l2 ... t2 = time.time() - t2 ... t3 = time.time() ... s3 = ''.join(l2) ... t3 = time.time() - t3 ... assert s1 == s2 ... assert s1 == s3 ... print t1, t2, t3 ... tester(x) 0.0551731586456 0.0251281261444 0.0264830589294 tester(x) 0.0585241317749 0.0239250659943 0.0256059169769 tester(x) 0.0544500350952 0.0271301269531 0.0232360363007 The order of magnitude now falls to a factor of two. The original version of the test on my box also showed an order of magnitude difference, so this isn't an implementation difference. This version still includes the overhead of the for loop in the test. The join idiom isn't enough faster to make a difference. py tester(x*10) 2888.56399703 0.13130998611 tester(x * 10) 1.22272014618 0.252701997757 0.27273607254 tester(x * 10) 1.21779584885 0.255345106125 0.242965936661 tester(x * 10) 1.25092792511 0.311630964279 0.241738080978 Here we get the addition idiom being closer to a factor of four instead of two slower. The .joim idiom is still nearly identical. mike -- Mike Meyer [EMAIL PROTECTED] http://www.mired.org/home/mwm/ Independent WWW/Perforce/FreeBSD/Unix consultant, email for more information. -- http://mail.python.org/mailman/listinfo/python-list
Re: Question about inheritance...
KraftDiner [EMAIL PROTECTED] writes: I have a base class called Shape And then classes like Circle, Square, Triangle etc, that inherit from Shape: My quesiton is can a method of the Shape class call a method in Circle, or Square etc...? Yup: class Shape(object): ... def commented_draw(self): ... print Drawing, self.__class__.__name__ ... self.draw() ... class Circle(Shape): ... def draw(self): ... print Drawing a Circle ... c = Circle() c.commented_draw() Drawing Circle Drawing a Circle Or maybe you meant invoking them directly, which a method in Shape would do by calling Circle.draw(self). The latter is ugly - you should use self.draw() to invoke the draw routine that's correct for self. mike -- Mike Meyer [EMAIL PROTECTED] http://www.mired.org/home/mwm/ Independent WWW/Perforce/FreeBSD/Unix consultant, email for more information. -- http://mail.python.org/mailman/listinfo/python-list
Re: High Order Messages in Python
[EMAIL PROTECTED] [EMAIL PROTECTED] writes: I'm reading about high order messages in Ruby by Nat Pryce, and thinking if it could be util and if so, if it could be done in Python. Someone already tried? Yes, I'm pretty sure it could be done in Python. All it really needs is the ability to catch references to undefined attributes, which Python has. You make the HOM of your collection class return an object with a reference to self, and the __getattr__ method of that classs then invokes getattr on each object in the referenced collection instance for the undefined method, manipulating the result as appropriate for that HOM, and returning a new list. But this really isn't a very good fit for Python. This is really a feature for more aggressively OO languages. To make the examples HOMs described really useful, you want to add them to some base class for collections. But that base class doesn't exist in Python - Python just isn't that OO. You could add various HOMs to lists, tuples, generators and iterators - but then anyone who wanted to create a new sequence class would have to add all of the HOMs that their clients might want to use. The pythonic way would be to add a function that works with all the various sequence types - which would then automatically work with any user-defined classes that quacked like a sequence. It's not very OO - but it is pythonic. In fact, Python already has functions that capture the functionality of the example HOMs in the links you posted: where and unless are handled by filter. in_order_of and in_reverse_order_of are handled by sorted. do is is handled by map. Of course, recent versions of python provide list comprehensions as preferable to some of these functions. That said, HOM's are a *very* powerful mechanism. The examples - and my discussion of them - cover just one very broad use case. There may be others where they are a better fit with Python. Having examples of how to do these kinds of things around is probably worthwhile. mike -- Mike Meyer [EMAIL PROTECTED] http://www.mired.org/home/mwm/ Independent WWW/Perforce/FreeBSD/Unix consultant, email for more information. -- http://mail.python.org/mailman/listinfo/python-list
Re: Microsoft Hatred FAQ
that both OSX and Linux competed with it. I guess it hasn't sunk in yet that the existence of competition doesn't keep a company from being a monopoly. But it does. Companies that owned less of their market than MS owns of it's market have been broken up. A classic monopoly behavior is to want the competition to survive just barely, because that gives them leverage in court. Which is why MS has helped out Apple in the past. There is no way Microsoft could have expected the market to be defined in this way and no way to argue that Microsoft had any reason to believe their conduct was illegal. Microsoft have lawyers. Microsoft destroyed emails and at least one senior manager perjured himself in court. Microsoft created a fake video demonstration which they then gave as evidence. Do you really believe that Microsoft's executives are so incompetent that they don't get legal advice before writing up contracts? Or that nobody in authority at Microsoft realised that destroying evidence and lying to a judge are crimes? When a criminal willing to use force points a gun at your head, you lie to him. You sound like an anarchist to me. This wasn't a criminal, this was the government. Lieing to random individuals isn't a crime. Lieing to the government is. In any case, even if you are right that Microsoft had no ideas... so what? Ignorance of the law never has been an excuse for criminal behaviour. It has always been every individual's responsibility to make sure that they do not act illegally, and that goes for companies as well. I am not saying Microsoft did not know the law. I am saying that no rational person could have expected the law to be applied to Microsoft that way it was. The law *must* put a person on notice of precisely what conduct it prohibits. However, in this case, the law's applicability was conditioned on an abritrary and irrational choice of what the relevant market was. MS has a long history of dancing with the DOJ, and has been repeatedly warned about the legality - or lack thereof - of their behavior. No rational person who knew of that history could expect the law to be applied to MS in any way other than the way it was. mike -- Mike Meyer [EMAIL PROTECTED] http://www.mired.org/home/mwm/ Independent WWW/Perforce/FreeBSD/Unix consultant, email for more information. -- http://mail.python.org/mailman/listinfo/python-list
Re: Python vs Ruby
Steven D'Aprano [EMAIL PROTECTED] writes: On Fri, 21 Oct 2005 13:03:29 +0100, Alex Stapleton wrote: Perl is more like a CISC CPU. There are a million different commands. Python is more RISC like. Line count comparisons = pointless. Not so. Every line = more labour for the developer = more cost and time. Every line = more places for bugs to exist = more cost and time. There were studies done in the 70s that showed that programmers produced the same number of debugged lines of code a day no matter what language they used. So a language that lets you build the same program with fewer lines of code will let you build the program in less time. I find it sometimes helps to imagine extreme cases. Suppose somebody comes to you and says Hi, I want you to develop a web scrapping application to run on my custom hardware. You look at the project specifications and realise that the hardware has no OS, no TCP/IP, no file manager, no compiler. So you have to quote the potential customer on writing all these layers of software, potentially tens of millions of lines of code. Even porting an existing OS to the new hardware is not an insignificant job. Think how much time and money it would take. Then factor in the profits to be reaped from selling the ported OS/compilers :-). mike -- Mike Meyer [EMAIL PROTECTED] http://www.mired.org/home/mwm/ Independent WWW/Perforce/FreeBSD/Unix consultant, email for more information. -- http://mail.python.org/mailman/listinfo/python-list
Re: Binding a variable?
Steven D'Aprano [EMAIL PROTECTED] writes: On Fri, 21 Oct 2005 13:33:18 -0400, Mike Meyer wrote: Paul Dale [EMAIL PROTECTED] writes: Hi everyone, Is it possible to bind a list member or variable to a variable such that temp = 5 list = [ temp ] Don't use the names of built-in functions as variables. temp == 6 list would show list = [ 6 ] No. You need to either put a mutable in the list, or subclass list so that indexing gets the value, looks it up in the appropriate namespace, and returns that value. Or something even conceptually simpler than having to muck about with looking up different namespaces: [elided] Um, that's the *first* solution I proposed: putting a mutable on the list. mike -- Mike Meyer [EMAIL PROTECTED] http://www.mired.org/home/mwm/ Independent WWW/Perforce/FreeBSD/Unix consultant, email for more information. -- http://mail.python.org/mailman/listinfo/python-list
Re: Microsoft Hatred FAQ
David Schwartz [EMAIL PROTECTED] writes: Mike Meyer [EMAIL PROTECTED] wrote in message news:[EMAIL PROTECTED] Neither I, nor you, nor the government of any nation, should care a monkey's toss specifically for Microsoft's success. Microsoft is one special interest, out of a potentially unbounded number of possible players in the economy of a country and the world. No, not at all. It is the gravest act of self-contradiction to maintain that one should be allowed to pursue one's own interest while denying that same right to others. Not at all. No one is denying anyones right to purssue their own interest. What's being denied is the right to use illegal means to do so. If MS restricted themselves to legal means, no one would have a problem with them. The conclusion that the means were illegal is predicated on the definition of the relevent market as desktop operating systems for 32-bit x86 computers. Conduct is not illegal unless some law puts people on adequate notice that their conduct is illegal. What law put Microsoft on notice that the relevent market would be defined in the bizarre and almost nonsensical way? Not at all. The conclusion that the means were illegal was because *they worked*. If MS didn't have monopoly power, the people they were dealing with would have laughed at them. Unless you or I are specifically shareholders in Microsoft, we should not care about their specific success; and the government should be entirely agnostic about who are the winners and losers in an economy. We should certainly care that Microsoft be allowed to pursue their own success. The government should be agnostic about who the winners and losers are, but must respect each entity's right to attempt to be that winner. Nice thought. Unfortunately, the government doesn't work that way. They believe that a practical monopoly is a bad thing, and limit the things such a company can do, and have been known to disassemble companies they believe are harming the economy in general. In other words, they believe the rights of Microsoft to do what they please with what is theirs is subservient to some general obligation to help the economy as a whole. I am saying that Microsoft has no obligaiton to the economy as a whole but instead has an obligation to its stockholders. It would be the gravest dereliction of that obligation for Microsoft to sacrifice itself for some general benefit. You do like straw men, don't you? Nowhere in the what I said does the word help appear; you pulled it out of thin air, and what you said in general has *nothing* to do with what you quoted above. The statements don't contradict each other in any way, and both happen to be true. The government's role should be to ensure a level playing field, and minimum levels of health, safety and environmental standards. There is no place for government giving special-interests like Microsoft favours. The problem is, people complain when the playing field is in fact level. For example, Microsoft's exclusionary Windows agreements didn't ask for more than Windows was worth (or nobody would have agreed to them). Yet they are considered examples of the playing field not being level. No, they didn't ask for more than Windows were worth. They tilted the playing field against MS competitors by causing consumers to pay MS money for products they didn't receive. In most countries, taking money from unwilling victims without giving them anything in exchange is called theft. It is not theft if you can simply say no to the deal and all that happens is that you don't get the product. Your argument is preposterous. If you accept arguments that equate guns with arguments, the next step is that using a gun is a rational response to an argument one doesn't like. Oh wait, you're already there. Yup, we're there - and you brought us there, by referring to federal judges as criminals pointing guns. Of course, there are lots more straw men in this argument. I didn't mention guns at all - you manufactured that from nothing. Theft doesn't have to involve guns. Hell, it doesn't even have to involve the knowledge of the victim, which is the case here. Everyone buying a system from those that MS bullied paid for an MS OS, whether they got one or not, and wether they knew it or not - and MS got the money. They didn't even realize they were being robbed, so saying no was never an option. Microsoft's behaviour over-all has been just as anti-social, anti-competitive and harmful to the over-all running of the economy as a hypothetical Walmart or Safeway that regularly parked their trucks in the middle of the main road for a few hours while they unloaded. The problem is, the government does not own the economy. So it does not get to manage it the way it gets to manage the roads it in fact owns. Sorry, but you're wrong. The government *does* own the econnomy
Re: Python vs Ruby
[EMAIL PROTECTED] (Alex Martelli) writes: Mike Meyer [EMAIL PROTECTED] wrote: Every line = more labour for the developer = more cost and time. Every line = more places for bugs to exist = more cost and time. There were studies done in the 70s that showed that programmers produced the same number of debugged lines of code a day no matter what language they used. So a language that lets you build the same program with fewer lines of code will let you build the program in less time. Of course, these results only apply where the complexity (e.g., number of operators, for example) in a single line of code is constant. I'm not sure what you're trying to say here. The tests ranged over things from PL/I to assembler. Are you saying that those two languages have the same complexity in a single line? for item in sequence: blaap(item) or for item in sequence: blaap(item) are EXACTLY as easy (or hard) to write, maintain, and document -- it's totally irrelevant that the number of lines of code has doubled in the second (more standard) layout of the code!-) The studies didn't deal with maintenance. They only dealt with documentation in so far as code was commented. On the other hand, studies of reading comprehension have shown that people can read and comprehend faster if the line lengths fall within certain ranges. While it's a stretch to assume those studies apply to code, I'd personally be hesitant to assume they don't apply without some reseach. If they do apply, then your claims about the difficulty of maintaining and documenting being independent of the textual line lengths are wrong. And since writing code inevitable involves debugging it - and the studies specified debugged lines - then the line length could affect how hard the code is to write as well. mike -- Mike Meyer [EMAIL PROTECTED] http://www.mired.org/home/mwm/ Independent WWW/Perforce/FreeBSD/Unix consultant, email for more information. -- http://mail.python.org/mailman/listinfo/python-list
