Re: Python obfuscation
Alex Martelli wrote: It's interesting, in this context, that Civilization IV is mostly written in Python (interfaced to some C++ via BoostPython). It took me 12 seconds with a search engine to determine that CivIV's protection uses SafeDisc 4.60 and 30 more seconds to research that issue enough to convince myself that there's enough information out there that I could develop a crack for the thing (if I was interested in so doing), quite apart from any consideration of the languages and libraries used to develop it -- and I'm not even a particularly good cracker, nor am I wired into any underground channels, just looking at information easily and openly available out on the web and in the index of a major search engine. Yes, I never said it's uncrackable. The cracks available are iffy and the alternatives are sufficiently inconvenient to dissuade the less-savvy user from attempting them. In which case, the copy protection has succeeded. What I think of this thesis is on a par of what I think of this way of spelling the possessive adjective its (and equally unprintable in polite company). If I could choose to eradicate only one of these two from the world, I'd opt for the spelling -- the widespread and totally unfounded belief in the worth of obfuscation is also damaging, but less so, since it only steals some time and energy from developers who (if they share this belief) can't be all that good anyway;-). The level of pedantry here is amazing and it doesn't apply only to programming languages. While we are discussing my typos, I'd like to note that I may accidentally interchange you're and your, there, they're, and their, and a bunch of other homonyms. I hadn't seen any damage done from misusing it's. Certainly not on par with the Sony case which Mike Meyer cites as evidence against copy protection (and presumably obfuscation, which was the topic of the discussion) This topic seems to be drifting. I thought I might clarify what I mean by code obfuscation to get things back on track. Code obfuscation is a transformation of the program (whether at source code level, intermediate object code level, binary executable level, etc) to hinder (prevention seems impossible) reverse engineering (attempts to determine the workings of the code, to modify the function of the code, etc). While there are many possible transformations that can be done on programs (compression, run-time optimizations, etc), the key here is the intent to hinder reverse engineering. I hope this is agreeable to everyone. Python already conveniently supports certain transformations on programs. Off the top of my head, I think of compiled bytecode (pyc and pyo files), and modules in zip archives. Any of these can be used as a means of obfuscation. (Compiled languages naturally undergo transformations which tend to have more effectiveness against reverse engineering) Now, to address points made by Mike Meyer. He says that obfuscation adds steps to the release process and also cites Sony's XCP fiasco as an example of unseen costs of copy protection. Indeed, everything has a cost, and I was wrong in saying free. However, if convenient language-supported transforms are used, the direct cost of using obfuscation would be miniscule in comparison to just about everything else. Implementing it should be one simple step, and testing it shouldn't be required (if you reasonably assume the language isn't broken). I am going to ignore certain aspects of the Sony XCP case, such as the bad EULA and the bad PR (we shall leave that to the lawyers and marketing folk and stick to something we programmers can actually fix). What we have left is a broken software implementation of copy protection. If language-supported (or even OS-supported, which would have helped Sony*) transformations are used, we can expect to rule out such brokenness, i.e. no obfuscation-induced incompatibilities and related help-desk calls. This further reduces the unexpected costs of code obfuscation to zero (did I miss anything?) This form of obfuscation is certainly weak, but given that the costs are so tiny, why not use it? Even if you could gain one customer (and a few dollars if you're a shareware developer), you have more than recuperated your costs. If you don't, you probably lost 5 minutes of development time. Is this a worthwhile gamble? I believe so. Mike Meyer may reiterate his point about keeping honest people honest and thus such obfuscation has little (insignificant) benefit. Whether this little difference is insignificant is up to the developer/publisher/etc to decide. My thesis (to borrow Alex Martelli's language) is that it is possible to obtain *some* benefit from obfuscation with *minimal* costs. There are physical examples of attempts to hinder reverse engineering: glueing the cases of devices shut and sealing integrated circuits in a blob of epoxy, among others. With such examples, I don't
Re: about widget construction kit
very hard for me to understand the difference between try...except and try...finally -- http://mail.python.org/mailman/listinfo/python-list
about try statement
very hard for me to understand the difference between try...except and try...finally -- http://mail.python.org/mailman/listinfo/python-list
Re: Python obfuscation
Alex Martelli wrote: There is no effective manner of protecting your code, except running it only on well-secured machines you control yourself. If you distribute your code, in ANY form, and it's at all interesting to people with no interest in respecting the law, then, it WILL be cracked (and if users choose to respect the law, then you need no protecting). Indeed. An this extends to web services too. If you have input which can be observed (or even better, controlled) and output that can be observed too, one would be able to infer the workings of the code (reverse engineering in one of its purest forms). If your business strategy relies heavily on a proprietary algorithm or even something as weak as lock-in via a proprietary un-interoperable data format, then web services is not the final answer. It may work for certain applications (Microsoft's for example) where the cost of reverse engineering is equivalent to the cost of building from scratch. -- http://mail.python.org/mailman/listinfo/python-list
Re: about try statement
Shi Mu enlightened us with: very hard for me to understand the difference between try...except and try...finally Within a 'try' block, if an exception is called and a matching 'except' block is found, that block will be used to handle the expression. From the documentation of the return keyword: When return passes control out of a try statement with a finally clause, that finally clause is executed before really leaving the function. Note that there is no talk about exceptions in this. Sybren -- The problem with the world is stupidity. Not saying there should be a capital punishment for stupidity, but why don't we just take the safety labels off of everything and let the problem solve itself? Frank Zappa -- http://mail.python.org/mailman/listinfo/python-list
Re: help make it faster please
Bengt Richter enlightened us with:
I suspect it's not possible to get '' in the list from
somestring.split()
Time to adjust your suspicions:
';abc;'.split(';')
['', 'abc', '']
countDict[w] += 1
else:
countDict[w] = 1
does that beat the try and get versions? I.e., (untested)
try: countDict[w] += 1
except KeyError: countDict[w] = 1
OPs way is faster. A 'try' block is very fast, but trowing handling
an exception is slow.
countDict[w] = countDict.get(w, 0) + 1
I think this has the potential of being faster than OPs method,
because it's likely to be fully implemented in C.
Sybren
--
The problem with the world is stupidity. Not saying there should be a
capital punishment for stupidity, but why don't we just take the
safety labels off of everything and let the problem solve itself?
Frank Zappa
--
http://mail.python.org/mailman/listinfo/python-list
passing values from one form to another
hi i have 3 python cgi scripts created, one is a login page(login.py), another is the main page(main.py) with a lot of user inputs and the last one is a python cgi script results.py to process main.py In main.py, i am able to check for the value of the user and password field, eg if form.has_key(user) and form[button].value == Login and form.has_key(password): # show all fields how can i also check for the user field in the results.py script? ie , pass the value of the user to the python script..so that user must always login to get to results.py thanks.. -- http://mail.python.org/mailman/listinfo/python-list
JAPH
import sys charset = .JPacehknorstuy modulo = 17 s = 69859911049503515105680510599913390885187193231927247909305172858127641629 num = iter(range(2, )) while s != 1 : n = num.next() if s % n == 0 : sys.stdout.write(%s % charset[(n - 1) % modulo]) s /= n #end if #end while sys.stdout.write(\n) -- http://mail.python.org/mailman/listinfo/python-list
Re: [ x for x in xrange(10) when p(x) ]
Peter Otten wrote: [EMAIL PROTECTED] wrote: However, I found something interesting which I don't quite understand : list((x for x in [1,2,3] if x2 or stop())) works but a = [ x for x in [1,2,3] if x 2 or stop() ] doesn't. Here's how Carl Banks explained it to me when Bengt came up with this trick. http://mail.python.org/pipermail/python-list/2005-April/274051.html Thanks, but that is even more confusing for me. I thought it is the for that trap the StopIteration as in : for x in iteratables: pass But it said it is not ? -- http://mail.python.org/mailman/listinfo/python-list
Re: help make it faster please
Thank you Bengt Richter and Sybren Stuvel for your comments, my little procedure can be improved a bit in many ways, it was just a first quickly written version (but it can be enough for a basic usage). Bengt Richter: good way to prepare for split Maybe there is a better way, that is putting in just the accepted letters and accented letters, instead of the not accepted symbols. I suspect it's not possible to get '' in the list from somestring.split() You are probably right, the algorithm used is different if you don't give a splitting string: ' abc a '.split() ['abc', 'a'] '.abc..a.'.split(.) ['', 'abc', '', 'a', ''] does that beat the try and get versions? I.e., (untested) Yes. countDict[w] = countDict.get(w, 0) + 1 I think the if-else version is the fastest, I have tested it a long time ago... You can easely do a speed test to see if I am wrong. Bear hugs, bearophile -- http://mail.python.org/mailman/listinfo/python-list
Re: [ x for x in xrange(10) when p(x) ]
On Sat, 12 Nov 2005 08:12:43 +0100, Peter Otten [EMAIL PROTECTED] wrote: [EMAIL PROTECTED] wrote: However, I found something interesting which I don't quite understand : list((x for x in [1,2,3] if x2 or stop())) works but a = [ x for x in [1,2,3] if x 2 or stop() ] doesn't. Here's how Carl Banks explained it to me when Bengt came up with this trick. http://mail.python.org/pipermail/python-list/2005-April/274051.html Thanks (I guess, or is guilt being pinned? ;-) for the attribution. BTW, that thread is easier to follow on google: http://groups.google.com/group/comp.lang.python/browse_thread/thread/ca7ba6ca9d70d24c/fdcadd1e3eba61cd But googling shows I wasn't the first to come up with iter([]).next() to raise Stopiteration. Usual suspect: http://groups.google.com/group/comp.lang.python/browse_thread/thread/41495e4f5d3e1c2a/84c158ff18d08ece#84c158ff18d08ece It probably stuck subconsciously in my mind and just came back when I wanted a StopIteration expression for terminating a generator expression. Regards, Bengt Richter -- http://mail.python.org/mailman/listinfo/python-list
about array,arange
i got confused by the use of array and arange. arange get array and range get list, why we need the two different types? -- http://mail.python.org/mailman/listinfo/python-list
Re: Python obfuscation
The Eternal Squire [EMAIL PROTECTED] writes: Without copyright, how could one possibly earn a living writing a novel? This guy seems to be doing ok: http://craphound.com His publishers are the only ones allowed to sell his novels commercially, but you can download them all and print them out noncommercially for your own personal enjoyment or to share with your friends. No obfuscation is needed. And I submit that many ISD's are only a single person burning with that one software idea of a lifetime, the equivalent of the Great American Novel. Are we to punish that impulse by denying that person a legal monopoly on that idea? You know, there's lots of people who would like to make a living as actors or musicians or novelists or whatever, and maybe they even have enough talent and skill to do it, but for whatever reason it's just not in the cards for them, copyright or not. So they do other things instead. Maybe it's also not in the cards for some people to be programmers even though they'd like to be, so they do other things instead too. For the most part, I don't feel any sense of tragedy about this. I believe piracy is bad for everyone: the consumer, the writer, and the country as a whole. I don't oppose copyleft, but then, I don't oppose copyright either. Let's distribute the former for free, and honor the need for the writer of the latter to earn a living. Everyone has the right to try to earn a living from programming, but no one is entitled to be guaranteed success at it. -- http://mail.python.org/mailman/listinfo/python-list
Re: help make it faster please
On Sat, 12 Nov 2005 10:46:53 +0100, Sybren Stuvel [EMAIL PROTECTED] wrote:
Bengt Richter enlightened us with:
I suspect it's not possible to get '' in the list from
somestring.split()
Time to adjust your suspicions:
';abc;'.split(';')
['', 'abc', '']
I know about that one ;-)
I meant somestring.split() just like that -- without a splitter argument.
My suspicion remains ;-)
countDict[w] += 1
else:
countDict[w] = 1
does that beat the try and get versions? I.e., (untested)
try: countDict[w] += 1
except KeyError: countDict[w] = 1
OPs way is faster. A 'try' block is very fast, but trowing handling
an exception is slow.
Yes, so it's data sensitive. Same with the other one not mentioned:
countDict.setdefault(w, [0])[0] += 1 # accum count in
length one list vs as int
# too much
subscripting work though
countDict[w] = countDict.get(w, 0) + 1
I think this has the potential of being faster than OPs method,
because it's likely to be fully implemented in C.
Not sure what you mean. Don't forget, all those expressions are evaluated
dynamically
step by step with byte codes being switched on in c, but still a bunch of
steps. I.e.,
import dis
dis.dis(compile('countDict[w] = countDict.get(w, 0) + 1', '', 'exec'))
1 0 LOAD_NAME0 (countDict)
3 LOAD_ATTR1 (get)
6 LOAD_NAME2 (w)
9 LOAD_CONST 0 (0)
12 CALL_FUNCTION2
15 LOAD_CONST 1 (1)
18 BINARY_ADD
19 LOAD_NAME0 (countDict)
22 LOAD_NAME2 (w)
25 STORE_SUBSCR
26 LOAD_CONST 2 (None)
29 RETURN_VALUE
Looks like if you succeed most of the time without a KeyError, the try/except
might be
a tad faster, depending on what the exception block setup/teardown costs.
dis.dis(compile(\
... try: countDict[w] += 1
... except KeyError: countDict[w] = 1
... , '', 'exec'))
1 0 SETUP_EXCEPT20 (to 23)
3 LOAD_NAME0 (countDict)
6 LOAD_NAME1 (w)
9 DUP_TOPX 2
12 BINARY_SUBSCR
13 LOAD_CONST 0 (1)
16 INPLACE_ADD
17 ROT_THREE
18 STORE_SUBSCR
19 POP_BLOCK
20 JUMP_FORWARD29 (to 52)
223 DUP_TOP
24 LOAD_NAME2 (KeyError)
27 COMPARE_OP 10 (exception match)
30 JUMP_IF_FALSE 17 (to 50)
33 POP_TOP
34 POP_TOP
35 POP_TOP
36 POP_TOP
37 LOAD_CONST 0 (1)
40 LOAD_NAME0 (countDict)
43 LOAD_NAME1 (w)
46 STORE_SUBSCR
47 JUMP_FORWARD 2 (to 52)
50 POP_TOP
51 END_FINALLY
52 LOAD_CONST 1 (None)
55 RETURN_VALUE
Regards,
Bengt Richter
--
http://mail.python.org/mailman/listinfo/python-list
Re: about widget construction kit
Shi Mu wrote: I tried again and got the follwoing message: *** cannot find Tcl/Tk headers and library files change the TCL_ROOT variable in the setup.py file but i have already installed TCL under python23 hmm. I still think it would be easier if you used a prebuilt version, like everyone else. (if you insist on using an old source release instead of the latest binaries, follow the instructions, and make sure the TCL_ROOT variable points to the location of the Tcl/Tk development libraries (the directory that con- tains Tcl's include and lib directories, that is)) /F -- http://mail.python.org/mailman/listinfo/python-list
911, need drvmcdb.sys desperately
Hi, Sorry to post this message, but I need emergency help, please help me out! I couldn't get drvmcdb.sys from internet, which I accidentally deleted last night, my laptop (XP) couldn't reboot anymore, but I need to keep my data. If anybody can send me this file: which is located in c:\windows\system32\drivers\drvmcdb.sys Please send it to [EMAIL PROTECTED], coz I couldn't use this account from tomorrow I will appreciate your BIG HELP so much! You are my life saver! Regards, James -- http://mail.python.org/mailman/listinfo/python-list
Re: JAPH
charset, modulo, japh = .JPacehknorstuy, 17, s = 69859911049503515105680510599913390885187193231927247909305172858127641629 for n in xrange(2,): if s%n==0: japh += charset[(n - 1) % modulo] s /= n if s==1: break print japh -- http://mail.python.org/mailman/listinfo/python-list
Re: Recommendation please: forming an XML toolkit
[EMAIL PROTECTED] wrote: I guess you're right... I think its just cold feet from the possibility of getting involved and discovering specific gotchas later. What I'm hearing you tell me is *go and play it*. uche posted an interesting taxonomy here: http://article.gmane.org/gmane.comp.python.xml/3605 once you decide what kind of XML processing you're doing, you can usually find one or two best-of-breed toolkits within each category. /F -- http://mail.python.org/mailman/listinfo/python-list
Re: about try statement
On Sat, 12 Nov 2005 10:20:08 +0100, Sybren Stuvel [EMAIL PROTECTED] wrote: Shi Mu enlightened us with: very hard for me to understand the difference between try...except and try...finally Within a 'try' block, if an exception is called and a matching 'except' block is found, that block will be used to handle the expression. From the documentation of the return keyword: When return passes control out of a try statement with a finally clause, that finally clause is executed before really leaving the function. Note that there is no talk about exceptions in this. Which is because in the finally block the exception is still live and will take effect as soon as the finally block is left, e.g., try: ... try: 1/0 ... finally: print 'exception can not bypass finally' ... except Exception, e: ... print '%s: %s' %(e.__class__.__name__, e) ... exception can not bypass finally ZeroDivisionError: integer division or modulo by zero Or to make the point about return def foo(den): ... try: ... try: return 1/den ... finally: print 'exception can not bypass finally' ... except Exception, e: ... print '%s: %s' %(e.__class__.__name__, e) ... return 'succeeded in returning something' ... foo(0) exception can not bypass finally ZeroDivisionError: integer division or modulo by zero 'succeeded in returning something' foo(1) exception can not bypass finally 1 Regards, Bengt Richter -- http://mail.python.org/mailman/listinfo/python-list
Re: about array,arange
Shi Mu wrote: i got confused by the use of array and arange. arange get array and range get list, why we need the two different types? When you're asking questions about a third-party module, it's a good idea to mention the module. In this case you're asking about scipy_core (hopefully) or else numarray or Numeric. The answer to your question is that sometimes we need to get largish arrays (not lists) of consecutive numbers quickly. array(range(N)) is wasteful of memory and time because it has to create a list of Python ints that are simply going to be thrown away once we're done converting to the needed array. -- Robert Kern [EMAIL PROTECTED] In the fields of hell where the grass grows high Are the graves of dreams allowed to die. -- Richard Harter -- http://mail.python.org/mailman/listinfo/python-list
Re: about array,arange
On 11/12/05, Robert Kern [EMAIL PROTECTED] wrote: Shi Mu wrote: i got confused by the use of array and arange. arange get array and range get list, why we need the two different types? When you're asking questions about a third-party module, it's a good idea to mention the module. In this case you're asking about scipy_core (hopefully) or else numarray or Numeric. The answer to your question is that sometimes we need to get largish arrays (not lists) of consecutive numbers quickly. array(range(N)) is wasteful of memory and time because it has to create a list of Python ints that are simply going to be thrown away once we're done converting to the needed array. -- Robert Kern [EMAIL PROTECTED] sorry to forget to mention the module name : Numeric -- http://mail.python.org/mailman/listinfo/python-list
Re: weird problem with os.chmod
Mike Meyer wrote: Strange that int doesn't recognize the leading 0. But you can use the second argument to int: int(0600, 16) 1536 int is designed for humans, not C programmers. humans tend to view e.g. 08 as a valid decimal number (*), not a ValueError. to get programmer behaviour, pass in 0 as the base: int(10, 0) 10 int(010, 0) 8 int(0x10, 0) 16 /F *) unless you're living in sweden, in which case 08 is quite often used as an insult. -- http://mail.python.org/mailman/listinfo/python-list
Re: about widget construction kit
On 11/12/05, Fredrik Lundh [EMAIL PROTECTED] wrote: Shi Mu wrote: I tried again and got the follwoing message: *** cannot find Tcl/Tk headers and library files change the TCL_ROOT variable in the setup.py file but i have already installed TCL under python23 hmm. I still think it would be easier if you used a prebuilt version, like everyone else. (if you insist on using an old source release instead of the latest binaries, follow the instructions, and make sure the TCL_ROOT variable points to the location of the Tcl/Tk development libraries (the directory that con- tains Tcl's include and lib directories, that is)) what is Tcl/Tk development libraries? I have a tcl folder under c:\python23. Is that what you mean? Regards, -- http://mail.python.org/mailman/listinfo/python-list
Re: Python obfuscation
Yu-Xi Lim [EMAIL PROTECTED] wrote: Code obfuscation is a transformation of the program (whether at source code level, intermediate object code level, binary executable level, etc) to hinder (prevention seems impossible) reverse engineering (attempts to determine the workings of the code, to modify the function of the code, etc). While there are many possible transformations that can be done on programs (compression, run-time optimizations, etc), the key here is the intent to hinder reverse engineering. That's a workable definition. I hope this is agreeable to everyone. The definition is agreeably solid. The intention is disagreeably sickening. -- \ Room service? Send up a larger room. -- Groucho Marx | `\ | _o__) | Ben Finney -- http://mail.python.org/mailman/listinfo/python-list
Re: tutorial example
That is the diference between a method and a function. A method do something and a function return something. Example: def psum(n, m): print (n + m) def rsum(n, m): return (n +m) Then try this... psum(2, 3) a = psum(2, 3) a a = rsum(2, 3) a You see it? -- http://mail.python.org/mailman/listinfo/python-list
Re: What do you use as symbols for Python ?
Gary == Gary Herron [EMAIL PROTECTED] writes:
Gary Erik Max Francis wrote:
Pierre Barbier de Reuille wrote:
When you need some symbols in your program, what do you use in
Python ?
For example, an object get a state. This state is more
readable if expressed as a symbols, for example opened,
closed, error. Typically, in C or C++, I would use an
enum for that: enum OBJECT_STATE { opened, closed, error
}
OPENED, CLOSED, ERROR = range(3)
object.state = OPENED
Gary Another similar approach that keeps those values together in
Gary a single namespace is this (my favorite):
Gary class State: OPENED, CLOSED, ERROR = range(3)
Gary Then you can refer to the values as State.OPENED
Gary State.CLOSED State.ERROR
Gary The extra clarity (and slight wordiness) of the dotted
Gary notation seems, somehow, quite Pythonic to me.
Gary Gary Herron
I think Zoran Isailovski has the last word on the topic:
http://aspn.activestate.com/ASPN/Cookbook/Python/Recipe/413486
--
http://mail.python.org/mailman/listinfo/python-list
Re: about widget construction kit
Shi Mu wrote: I tried again and got the follwoing message: *** cannot find Tcl/Tk headers and library files change the TCL_ROOT variable in the setup.py file but i have already installed TCL under python23 hmm. I still think it would be easier if you used a prebuilt version, like everyone else. (if you insist on using an old source release instead of the latest binaries, follow the instructions, and make sure the TCL_ROOT variable points to the location of the Tcl/Tk development libraries (the directory that con- tains Tcl's include and lib directories, that is)) what is Tcl/Tk development libraries? the stuff you get if you install tcl-devel/tk-devel on unix, or a complete Tcl/Tk distribution on Windows (e.g. ActiveTcl). I have a tcl folder under c:\python23. Is that what you mean? if you set TCL_ROOT to that directory and setup still says that it cannot find the development files, the answer is most likely no. can you explain why you cannot use a prebuilt version? /F -- http://mail.python.org/mailman/listinfo/python-list
Re: about array,arange
On 11/12/05, Robert Kern [EMAIL PROTECTED] wrote: Shi Mu wrote: i got confused by the use of array and arange. arange get array and range get list, why we need the two different types? When you're asking questions about a third-party module, it's a good idea to mention the module. In this case you're asking about scipy_core (hopefully) or else numarray or Numeric. The answer to your question is that sometimes we need to get largish arrays (not lists) of consecutive numbers quickly. array(range(N)) is wasteful of memory and time because it has to create a list of Python ints that are simply going to be thrown away once we're done converting to the needed array. -- Robert Kern [EMAIL PROTECTED] still not clear. can you give an example? Thanks! it is from numeric module (really confused by the documentation) -- http://mail.python.org/mailman/listinfo/python-list
Re: tutorial example
Not in python. For example, what would you call the following? def rsum(n, m): print n+m return n+m In python a method is callable attached to an object. A function is a callable object constructed with a def statement. max -- http://mail.python.org/mailman/listinfo/python-list
Re: about array,arange
Shi Mu wrote: On 11/12/05, Robert Kern [EMAIL PROTECTED] wrote: Shi Mu wrote: i got confused by the use of array and arange. arange get array and range get list, why we need the two different types? When you're asking questions about a third-party module, it's a good idea to mention the module. In this case you're asking about scipy_core (hopefully) or else numarray or Numeric. The answer to your question is that sometimes we need to get largish arrays (not lists) of consecutive numbers quickly. array(range(N)) is wasteful of memory and time because it has to create a list of Python ints that are simply going to be thrown away once we're done converting to the needed array. still not clear. can you give an example? Thanks! it is from numeric module (really confused by the documentation) An example of what? How to use arange()? I can't explain it any more clearly than the docstring does. In [1]: from Numeric import arange In [2]: arange? Type: builtin_function_or_method Base Class: type 'builtin_function_or_method' String Form:built-in function arange Namespace: Interactive Docstring: arange(start, stop=None, step=1, typecode=None) Just like range() except it returns an array whose type can be specified by the keyword argument typecode. -- Robert Kern [EMAIL PROTECTED] In the fields of hell where the grass grows high Are the graves of dreams allowed to die. -- Richard Harter -- http://mail.python.org/mailman/listinfo/python-list
Re: tutorial example
On 11/12/05, Max Erickson [EMAIL PROTECTED] wrote: Not in python. For example, what would you call the following? def rsum(n, m): print n+m return n+m In python a method is callable attached to an object. A function is a callable object constructed with a def statement. You are right, i was trying to explain the concept outside the objects. PD: I would call your example: a function. Without the return declaration, a routine or a method. -- http://mail.python.org/mailman/listinfo/python-list
SciPy python 2.4 wintel binaries
Hi, I dearly miss having the power of SciPy on my python 2.4 installation. The topic of SciPy python 2.4 wintel binaries has been discussed before on this list, but I haven't been able to find a compiled binary. I'm one of the 'compiled-challenged'; anything more complex than 'python setup.py build' leaves me at the grace of the non-challenged... SciPy is a complex software engineering project, so I'm hangin on the mercy of others here... Is anyone on this list aware of such a binary? Thanks, -jelle -- http://mail.python.org/mailman/listinfo/python-list
convert string to the escaped string
Hi, I am trying to convert string to the escaped string. example: from 0xf I need \0xf I am able to do it like: a=0xf escaped_a=(\%s % a ).decode(string_escape) But it looks a little bit complicated in this beautiful language to me Regards Petr Jakes -- http://mail.python.org/mailman/listinfo/python-list
Re: convert string to the escaped string
small mistake in my previous posting, sorry from 0xf I need \xf of course and mentioned code gives me \0xf of course. Thanks for your postings Petr Jakes -- http://mail.python.org/mailman/listinfo/python-list
Re: convert string to the escaped string
Petr Jakes wrote: I am trying to convert string to the escaped string. example: from 0xf I need \0xf I am able to do it like: a=0xf escaped_a=(\%s % a ).decode(string_escape) But it looks a little bit complicated in this beautiful language to me I suspect that optimizing for people who want to turn 0xf into chr(0) + xf isn't exactly a priority... if that's really what you want, of course. are you sure you didn't mean to write, say chr(int(0xf, 0)) (that is, convert 0xf to a character) or repr(chr(int(0xf, 0))) (that is, convert 0xf to a character, and convert that character to a string literal) ? /F -- http://mail.python.org/mailman/listinfo/python-list
Re: changeing users on linux
On Fri, Nov 11, 2005 at 11:25:56PM -0500, Mike Meyer wrote: You didn't say what the password was for, so I skipped asking for it. You're a real comedian. Jeff pgpxqmFz5jalu.pgp Description: PGP signature -- http://mail.python.org/mailman/listinfo/python-list
Re: tutorial example
Ruben Charles wrote: That is the diference between a method and a function. A method do something and a function return something. This is not quite correct. The difference between a method and a function is that the method is associated with a type or class object, a function is not. A method can be bound to a particular instance of an object or it can be unbound. In the latter case the first argument of the method call should be an instance of the type or class object. However, there is no builtin check to ensure that the first argument is in fact an instance. Please see the little example below. Colin W. # areaToy.py class Point(object): def __init__(self, x, y): self.x= x self.y= y class Area(object): def __init__(self, *pts): ''' pts is a list of points describing the enclosing polygon, in clockwise order, instances of Point. ''' self.pts= pts[0] def size(self): nPts= len(self.pts) if nPts 3: return 0 elif nPts == 3: return 0.5 # replace this with triangle area calc else: pts= self.pts return Area(pts[0:2] + [pts[-1]]).size() +\ Area(pts[1:]).size() pts= [Point(*pt) for pt in [(0, 1), (1, 1), (1, 0), (0, 0)]] area= Area(pts) size= area.size() print 'points:', pts print 'size:', size print 'Area.size:', Area.size print 'area.size:', area.size Example: def psum(n, m): print (n + m) def rsum(n, m): return (n +m) Then try this... psum(2, 3) a = psum(2, 3) a a = rsum(2, 3) a You see it? -- http://mail.python.org/mailman/listinfo/python-list
Re: What do you use as symbols for Python ?
Peter Otten wrote: You should ditch what follows and instead add just def __iter__(self): return iter(self.__keys) Mhh. I should start learning the builtins ... :) To see the problem with your original code (an object serving as its own iterator) try the following example: friends = Enum(Eric, Kyle, Stan, Kenny) if Kyle in friends: print Hi Kyle print My friends:, , .join(friends) Only Stan and Kenny show up in the last print statement because the containment test did not iterate over all friends. Never would have thought of this... Makes it even easier. Also, Type.__name seems redundant. Just class Type(str): pass should do the job. Right, works just fine. I'm not used to types, meanwhile I replaced Type(str) by a simple class Type, works as well. Thanks a lot, I was starting to integrate this solution in my code, now I can fix it before it's even used :) Daniel -- http://mail.python.org/mailman/listinfo/python-list
Re: Dynamically Update Class Definitions?
Jean-Paul Calderone wrote: There are lots of cases where you cannot rebind the __class__ attribute. For a comprehensive treatment of this idea (but still not a completely functionality implementation), take a look at http://cvs.twistedmatrix.com/cvs/trunk/twisted/python/rebuild.py?view=markuprev=11450. On another note, the usage of threads in this code is totally insane and unsafe. Even for strictly development purposes, I would expect it to introduce so many non-deterministic and undebuggable failures as to make it cost more time than it saves. You really want to stop the rest of the program, then update things, then let everything get going again. I used a thread to quickly detect changes in the source code, but you're absolutely right. In any non-toy application you'll definitely need control over when the upgrade process occurs. Thanks for the help. Chris -- http://mail.python.org/mailman/listinfo/python-list
Tkinter and the re/sizing of columns in a grid
I'm using grid() to lay out a column of Labels and a column of Entries in a frame. If the user changes an Entry so that it's bigger than its allotted space, i'd like to widen that column to show the entire string. I've tried parentFrame.columnconfigure(1, minsize=newSize), but that doesn't change anything. I'm obviously missing something. How should i go about this? More generally, can anyone point me to info on how to do calculated sizing and resizing of grids? thanks, Eric -- A strong smell of turpentine prevails throughout. -- Dr. Oliver Wendell Holmes -- http://mail.python.org/mailman/listinfo/python-list
Re: weird problem with os.chmod
Gary Herron wrote:
James Colannino wrote:
James Colannino wrote:
So then I entered the command print 0600, and saw that the actual
number being output was 384 (why would it output 384?!)
Ok, so further research revealed that 0600 is actually the octal
representation for 384 (which makes sense.) So then, I guess my
question would have to be, is there a way for me to make Python aware
that the 0600 I'm passing to int() is octal and not decimal so that I
will get 384 instead of 600?
int('0600',8) will do, but why would you want to do that?
Any of
x = 0600
x = 384
x = 0x180
x = int('0600',8)
will bind x to the same value (11000 in binary if you care).
But once you've got the valued defined, through whatever human readable
representation you want, the command
chmod(filename, x)
can be issued without further thought.
He reads the string ('0600' in this case, but I guess it can be any
permission) from a file. So he doesn't have the numerical value to begin
with.
BTW, I guess it's safer to do int(permission, 8) than int(permission,
0), since the first digit isn't guaranteed to be zero: it is used for
set user ID, set group ID and the sticky bit.
--
If I have been able to see further, it was only because I stood
on the shoulders of giants. -- Isaac Newton
Roel Schroeven
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Re: tutorial example
Ruben Charles wrote: That is the diference between a method and a function. A method do something and a function return something. I'd rather say it's the difference between a procedure and a function, as it is used in e.g. Pascal. Procedures in Pascal don't return anything, more or less analogue to functions returning void in C/C++. -- If I have been able to see further, it was only because I stood on the shoulders of giants. -- Isaac Newton Roel Schroeven -- http://mail.python.org/mailman/listinfo/python-list
Re: passing values from one form to another
[EMAIL PROTECTED] wrote: hi i have 3 python cgi scripts created, one is a login page(login.py), another is the main page(main.py) with a lot of user inputs and the last one is a python cgi script results.py to process main.py In main.py, i am able to check for the value of the user and password field, eg if form.has_key(user) and form[button].value == Login and form.has_key(password): # show all fields how can i also check for the user field in the results.py script? ie , pass the value of the user to the python script..so that user must always login to get to results.py Use a session. Or pass the values as hidden form-fields, which gets pretty tedious. Diez -- http://mail.python.org/mailman/listinfo/python-list
ANN: pynakotheka v1.0
Hello out there, I'm really pleased to announce the first public release of Pynakotheka. Pynakotheka is a simple GPL-licensed python script which generates static HTML photo albums to be added to web sites or to be burnt in CDs. It includes some templates and it's easy to create more. It depends on python, CheetahTemplate, EXIF and PIL. Read more and download it from: http://inigo.katxi.org/devel/pynakotheka or http://www.terra.es/personal7/inigoserna/pynakotheka Of course, all comments, suggestions etc. are welcome. Best regards, -- Iñigo Serna [EMAIL PROTECTED] Katxijasotzaileak signature.asc Description: Esta parte del mensaje está firmada digitalmente -- http://mail.python.org/mailman/listinfo/python-list
newbie how do I interpret this?
Here's a small session
import re
p=re.compile('[a-z]+')
m=p.match('abb1a')
dir(m)
['__copy__', '__deepcopy__', 'end', 'expand', 'group', 'groupdict',
'groups', 'span', 'start']
help(m.groups)
Help on built-in function groups:
groups(...)
My question is. How do I interpret the hiven help info
groups(...)
alt1. Tough luck. There's no help. People are to busy to write
reference manuals.
alt 2. There are no parameters. The only possibility is m.groups()
alt3. Something else
Thanks Bob
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Re: Python obfuscation
Yu-Xi Lim [EMAIL PROTECTED] writes: Indeed, everything has a cost, and I was wrong in saying free. However, if convenient language-supported transforms are used, the direct cost of using obfuscation would be miniscule in comparison to just about everything else. Implementing it should be one simple step, and testing it shouldn't be required (if you reasonably assume the language isn't broken). Failng to test what you ship is simply poor engineering and poor marketing. If you're incompetent, you might skip those steps. Otherwise, you have to test with obfuscation in place. I am going to ignore certain aspects of the Sony XCP case, such as the bad EULA and the bad PR (we shall leave that to the lawyers and marketing folk and stick to something we programmers can actually fix). What we have left is a broken software implementation of copy protection. If language-supported (or even OS-supported, which would have helped Sony*) transformations are used, we can expect to rule out such brokenness, i.e. no obfuscation-induced incompatibilities and related help-desk calls. This further reduces the unexpected costs of code obfuscation to zero (did I miss anything?) You ignored the fact that the *act* of copy protection cost them customers. It wasn't the poor implementation or the EULA, it was the fact that people who were denied their fair use rights returned or refused to buy their product. The rest of it merely made it widely publicized. This form of obfuscation is certainly weak, but given that the costs are so tiny, why not use it? Even if you could gain one customer (and a few dollars if you're a shareware developer), you have more than recuperated your costs. If you don't, you probably lost 5 minutes of development time. Is this a worthwhile gamble? I believe so. And if instead you lose one customer because you've denied them their fair use rights, then your copy protection has lost you more in the form of a cost that you overlooked than all the costs you actually considered. Mike Meyer may reiterate his point about keeping honest people honest and thus such obfuscation has little (insignificant) benefit. Whether this little difference is insignificant is up to the developer/publisher/etc to decide. My thesis (to borrow Alex Martelli's language) is that it is possible to obtain *some* benefit from obfuscation with *minimal* costs. Actually, obfuscation by itself has *no* benefit. If all you do is obfuscate the code, none of the pirates will ever notice - they'll just copy the code without ever trying to read it. It's the copy protection mechanisms you're trying to obfuscate that gains you the alleged benefit. Once you provide a copy protection mechanism, obfuscation has some benefit, though the costs aren't clearly minimal, not if you're a cometent engineer. It's the benefits of the copy protection that I claim are insignificant. 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: changeing users on linux
[EMAIL PROTECTED] writes: the password is for loging into root The setuid call will fail unless you're already root. You can't, as some user other than root, change your userid, so the answer to the original question with the added restriction is You can't. 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 how do I interpret this?
[EMAIL PROTECTED] wrote: help(m.groups) Help on built-in function groups: groups(...) My question is. How do I interpret the hiven help info groups(...) alt1. Tough luck. There's no help. People are to busy to write reference manuals. they're busy writing reference manuals, you mean: http://docs.python.org/lib/match-objects.html alt 2. There are no parameters. The only possibility is m.groups() in this case, that happens to be the most common way to use the method. alt3. Something else the words built-in function means that the function is im- plemented in C, and is therefore outside the reach of Python's introspection mechanisms. In this case, there don't seem to be any custom docstring associated with this method, so the above is all help() can tell you at the moment. This may of course change in future releases. /F -- http://mail.python.org/mailman/listinfo/python-list
Re: convert string to the escaped string
Fredrik, thanks for your posting. I really appretiate your reply and your way how you kindly answer even stupid newbie's questions on this mailing list. I was trying: int(0xf) but I did not have idea about the optional base parameter for the int function. Thanks a lot. Petr -- http://mail.python.org/mailman/listinfo/python-list
Re: passing values from one form to another
[EMAIL PROTECTED] writes: In main.py, i am able to check for the value of the user and password field, eg if form.has_key(user) and form[button].value == Login and form.has_key(password): # show all fields how can i also check for the user field in the results.py script? ie , pass the value of the user to the python script..so that user must always login to get to results.py This isn't really a Python question. The canonical solution is to set a cookie to get the browser to pass the required information to the next form. 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 obfuscation
Yu-Xi Lim [EMAIL PROTECTED] wrote: Alex Martelli wrote: There is no effective manner of protecting your code, except running it only on well-secured machines you control yourself. If you distribute your code, in ANY form, and it's at all interesting to people with no interest in respecting the law, then, it WILL be cracked (and if users choose to respect the law, then you need no protecting). Indeed. An this extends to web services too. If you have input which can be observed (or even better, controlled) and output that can be observed too, one would be able to infer the workings of the code (reverse engineering in one of its purest forms). ...unless you have nonobservable state, of course, in which case the inference is conceptually impossible. For example, say that you have developed a new and revolutionary system to predict weather, much better than anything the competition has. You offer it as a for-pay web service, the customer-supplied inputs being the space-time coordinates at which prediction is required, while the customer-provided outputs are a vector of possible weather conditions each with an attached probability, just as they might be for ANY weather-prediction web service, except that (by hypothesis, or else you won't make much money on this;-) the outputs of your weather predictor match reality much better than the competitors'. To infer whatever would essentially mean to reinvent your whole revolutionary system from scratch. Much the same would apply if what your system is able to predict better than your competitors' is any other kind of phenomenon of economic interest in a sufficiently complex real-world system -- from interest rates to the probability that two would-be online daters will like each other. And it doesn't have to be prediction -- one famous system where ESR, as a consultant, advised his clients to keep their program a trade secret, was just a better heuristic than any of their competitors' for cutting a set of given shapes with automated tools out of a slab of wood, if I recall correctly... a problem that's computationally intractable to solve anything but heuristically, and a better heuristic saves wood, worktime, and/or wear and tear on the tools, therefore is worth money. In practice, you ARE going to be able to operate your system successfully bases on keeping a good innovative algorithm or heuristic secret, for a while -- until somebody else independently reinvents it (or, invents something even better, in which case your secret may become irrelevant). IP protection is a possibility, but copyright per se might be too weak, and whether patents apply in any given case is always controversial (Europe soundly defeated a proposed software patent directive, after a bitter fight, less than a year ago). If your business strategy relies heavily on a proprietary algorithm or even something as weak as lock-in via a proprietary un-interoperable data format, then web services is not the final answer. It may work for certain applications (Microsoft's for example) where the cost of reverse engineering is equivalent to the cost of building from scratch. ...and the latter is going to be the case for many important proprietary algorithms, as above exemplified. A cryptographically sound proprietary data format may be essentially impossible to break, too -- although, differently from many potential algorithms, it has per se no added value, and may run afoul of sensible legislation (or sensible would-be customers), such as Massachussets', mandating the use of standard data formats. Alex -- http://mail.python.org/mailman/listinfo/python-list
Re: Python obfuscation
Yu-Xi Lim [EMAIL PROTECTED] wrote: I hadn't seen any damage done from misusing it's. Certainly not on par You should see my pharmacy bill for Maalox... and my liver ain't too happy about it either;-) Alex -- http://mail.python.org/mailman/listinfo/python-list
Re: Python obfuscation
Paul Rubin http://[EMAIL PROTECTED] wrote: The Eternal Squire [EMAIL PROTECTED] writes: Without copyright, how could one possibly earn a living writing a novel? This guy seems to be doing ok: http://craphound.com His publishers are the only ones allowed to sell his novels commercially, but you can download them all and print them out noncommercially for your own personal enjoyment or to share with your friends. No obfuscation is needed. One might also quip (not truthfully in Cory's specific case, I hasten to add!-) that many of today's novels are intrinsically obfuscated enough to need no further technological help on that front;-). Quips aside, the question is a sensible one to ask -- not as a rhetorical question, as TES apparently intended, of course, and not just about novels (many different creative endeavours may require different answers). The novel as a specific literary form is not that old, just a few centuries, but the issues were not very different for many other literary forms over the ages and cultures, and many different answers have been given or attempted. For example, Virgil was writing poems (epic and otherwise), not novels, but that's not very relevant to the question of how he made a living; the classic solution, in his case, was to find rich patrons willing to pay him to do so. Of course, there are obvious problems with this model... for example, Virgil was paid to write the Aeneid because his patrons liked its patriotism (as well as its towering artistic qualities), but a work with equally good art but an anti-patriotic ideology would have been much harder to monetize at that time (and also risked landing the author in the soup, as Ovid found out, but that's another issue, quite unrelated to monetization). Zooming forwards a couple of millennia, we see the model of serialization -- having the novel published in periodic installments by a magazine. Avid readers, we're told, crowded the piers of New York waiting for ship to land which carried the magazine with the latest installment of some Dickens novel -- and Dumas and Sue, in France, had fully comparable success in similar ways. At that time, copyright existed, in theory, but practically wasn't very well enforced (most particularly, I believe, in the USA, where the probability of a British publisher of actually enforcing a copyright was laughably low...) -- nevertheless, the reasonable cheapness of magazines coupled with the readers' urgency for the next installment let these authors earn a comfortable living anyway. Here, the problem is presumably that you need VERY popular novels for this to work -- but then, a tiny fraction of novelists actually make a comfortable living from just their novels, even with today's monetization approaches. Modern equivalent of serialization (publishing one chapter at a time on the web, the next chapter to come only if the author receives enough payment for the previous one) have been attempted, but without much success so far; however, the holy grail of micropayments might yet afford a rebirth for such a model -- if paying for a chapter was extremely convenient and cheap, enough people might choose to do so rather than risk the next chapter never appearing. Remember that, by totally disintermediating publishers and bookstores, a novelist may require maybe 1/10th of what the book would need to gross in stores, in order to end up with the same amount of cash in his or her pockets. One could go on for a long time, but the key point is that there may or may not exist viable monetization models for all sorts of endeavours, including the writing of novels, depending on a lot of other issues of social as well as legal structures. Let's not be blinded by one model that has worked sort of decently for a small time in certain sets of conditions, into believing that model is the only workable one today or tomorrow, with conditions that may be in fact very different. Alex -- http://mail.python.org/mailman/listinfo/python-list
Re: newbie how do I interpret this?
[EMAIL PROTECTED] writes:
Here's a small session
import re
p=re.compile('[a-z]+')
m=p.match('abb1a')
dir(m)
['__copy__', '__deepcopy__', 'end', 'expand', 'group', 'groupdict',
'groups', 'span', 'start']
help(m.groups)
Help on built-in function groups:
groups(...)
My question is. How do I interpret the hiven help info
groups(...)
alt1. Tough luck. There's no help. People are to busy to write
reference manuals.
alt 2. There are no parameters. The only possibility is m.groups()
alt3. Something else
alt 3, specifically: No doc string, time to check the reference manual.
URL: http://docs.python.org/lib/match-objects.html says:
groups( [default])
Return a tuple containing all the subgroups of the match, from
1 up to however many groups are in the pattern. The default
argument is used for groups that did not participate in the
match; it defaults to None. (Incompatibility note: in the
original Python 1.5 release, if the tuple was one element
long, a string would be returned instead. In later versions
(from 1.5.1 on), a singleton tuple is returned in such cases.)
Since you don't have any groups in your re, groups is always going to
return (). You probably want group().
mike
--
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Independent WWW/Perforce/FreeBSD/Unix consultant, email for more information.
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Proposal for adding symbols within Python
Please, note that I am entirely open for every points on this proposal (which I do not dare yet to call PEP). Abstract This proposal suggests to add symbols into Python. Symbols are objects whose representation within the code is more important than their actual value. Two symbols needs only to be equally-comparable. Also, symbols need to be hashable to use as keys of dictionary (symbols are immutable objects). Motivations === Currently, there is no obvious way to define constants or states or whatever would be best represented by symbols. Discussions on comp.lang.python shows at least half a dozen way to replace symbols. Some use cases for symbols are : state of an object (i.e. for a file opened/closed/error) and unique objects (i.e. attributes names could be represented as symbols). Many languages propose symbols or obvious ways to define symbol-like values. For examples in common languages: In C/C++ : Symbols are emulated using Enums. In Haskell/OCaml : Symbols are defined by union types with empty constructors. Symbols are local to modules. In Prolog : Symbols are called atoms ... they are local to modules (at least in swi-prolog) In Ruby : Symbols are introduced be the : notation. :open is a symbol. Symbols are global. In LISP : Symbols are introduced by '. 'open is a symbol. Symbols are local to modules. Proposal First, I think it would be best to have a syntax to represent symbols. Adding some special char before the name is probably a good way to achieve that : $open, $close, ... are $ymbols. On the range of symbols, I think they should be local to name space (this point should be discussed as I see advantages and drawbacks for both local and global symbols). For example, for the state of the file object I would write : file.$open, file.$close, file.$error Then, given some other objects (say some other device which also may be opened) : assert f.state != dev.state would always hold if both objects use locally-defined symbols. The only way for these states to be equal would be, for example, for the device object to explicitly assign the file symbols : dev.state = file.$open By default, symbols should be local to the current module. Then, being in the module device_manager, this would hold: assert $opened == device_manager.$opened There should be a way to go from strings to symbols and the other way around. For that purpose, I propose: assert symbol(opened) == $opened assert str($opened) == opened Implementation == One possible way to implement symbols is simply with integers resolved as much as possible at compile time. The End === Thanks to those who read entirely this proposal and I hope this proposal will gather enough interests to become a PEP and someday be implemented, maybe (probably?) in a completely different way ;) Pierre -- http://mail.python.org/mailman/listinfo/python-list
Re: newbie how do I interpret this?
Thanks for the reply I didn't realise the meaning of built-in function. Also I thought that help( ) mirrored the info in reference manual, which it obviously does not. Thanks again for a good answer and the link. Bob -- http://mail.python.org/mailman/listinfo/python-list
Re: Python obfuscation
Paul Rubin http://[EMAIL PROTECTED] writes: The Eternal Squire [EMAIL PROTECTED] writes: Without copyright, how could one possibly earn a living writing a novel? This guy seems to be doing ok: http://craphound.com His publishers are the only ones allowed to sell his novels commercially, but you can download them all and print them out noncommercially for your own personal enjoyment or to share with your friends. No obfuscation is needed. Not really a good counterexample, because His publishers are the only ones allowed to sell his novels commercially is only possible because of copyright. Without that, anyone could take the downloadable copy of his novels and start competing with his publishers - presumably with lower overhead, because they didn't have to pay Cory. Asking about novels is an excellent question - it's one of the few forms of copyrightable material where it's not the final end product and you have to give the public access to the media for them to use it. If either one of those isn't true, you can probably find a business model that doesn't depend on copyright. 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: weird problem with os.chmod
On Fri, 11 Nov 2005 16:49:23 -0800, James Colannino wrote: Ok, so now I have a very interesting problem, this time related to os.chmod. I have the following in a text file: 0600. My script reads that number as a string and converts it to an integer for use with chmod. However, when I do this, instead of the rw-- permissions 0600 is the octal representation of 384. man chmod should help you. Just use perm = int(string, 8) instead of perm = int(string) when converting to int the string you read from the file. -- Saluti, Mardy http://interlingua.altervista.org -- http://mail.python.org/mailman/listinfo/python-list
Re: Hash map with multiple keys per value ?
Chris Stiles [EMAIL PROTECTED] wrote:
snoe [EMAIL PROTECTED] writes:
Are you looking for this type of thing?
class Test:
value = 900
No, what I'm trying to do is this, assume two sets of aliases:
a, b, c, d and e
x, y and z
a returns b c d and e, b returns a c d and e, x returns y and z, y returns x
and z etc.
Where any of the sets of aliases can grow or shrink at any time.
So, it seems a reasonable underlying representation would be a mapping
from item to set of items. Keeping N different sets for a set of N
aliases would appear a bit wasteful of memory (it's hard to say without
knowing usecases and performance desiderata...), so you might have all
aliases map to the same set of aliases and dynamically construct the
required result by subtracting the lookup key itself.
Another design issue is, however, how do you identify, when adding an
alias, what it's an alias of -- from previous posts I'll assume that all
aliases are 'names' for some (hopefully hashable) object, so we'll also
need a mapping from said object back to its set of aliases. Or, would
alias insertion just be of the form x aliases to y rather than x
names object XXX?
Also not clarified in terms of specs: when an alias is inserted, do you
need to check if it was already an alias for something else (in another
set) and [a] raise an exception or [b] silently remove it from the
previous set? That applies to the x names object XXX style but not
necessarily to the x aliases y style, unless in the latter case you
want to say ...replacing any previous aliases of x to change rather
than merge alias-sets. But it would then seem simpler to simply have a
separate removal function x doesn't alias to anything any longer, to
be optionally called before the insertion method.
So, I think there are enough questions open about the specs to warrant
more exploration. Under some given set of interpretations for the above
open questions, you might have, e.g. (untested code, and no special
attention paid to performance):
class Aliases(object):
def __init__(self):
self.d = {}
def lookup(self, x):
if x in self.d:
return self.d[x]-set([x])
else:
return set()
def alias(self, x, y):
dx = self.d.get(x,set([x]))
dy = self.d.get(y,set([y]))
self.d[x]=self.d[y]=dx+dy
def unalias(self, x):
if x in self.d:
self.d[x].remove(x)
if not self.d[x]: del self.d[x]
Perhaps by working on this concrete example (which likely has bugs,
being untested, and even more likely misinterpret some specs, since I'm
having to guess at quite a few details) you can nail down the exact kind
of API syntax and semantics that you require...? Once the specs are
entirely clear, we might (if needed) worry about efficiency, but that
seems somewhat premature at this stage...
Alex
--
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Re: Hash map with multiple keys per value ?
On Fri, 11 Nov 2005 22:55:53 +, Chris Stiles [EMAIL PROTECTED] wrote:
Hi --
I'm working on something that includes the concept of multiple aliases for a
particular object, where a lookup for any of the aliases has to return all the
others. The hack way of doing this was to have a dictionary where each
entry consisted of a list of all the aliases - with multiple references to the
same list from the various dictionary entries corresponding to each alias.
What about the particular object in this? If all the aliases refer to the
particular object, what does return all the others mean? All _what_
others?
All refer to the same particular object. Or do you want the names? If so,
What about the particular object? Or do you want a dict back that has all the
other alias names as keys all referring to the particular object? E.g.,
class Aliad(dict):
... def __getitem__(self, key):
... keyval = dict.__getitem__(self, key)
... return Aliad((k,v) for k,v in self.items() if k!=key and v is
keyval)
...
po = 'particular object'
ad = Aliad(x=po, y=po, z=po)
ad
{'y': 'particular object', 'x': 'particular object', 'z': 'particular object'}
ad['x']
{'y': 'particular object', 'z': 'particular object'}
ad['y']
{'x': 'particular object', 'z': 'particular object'}
ad['z']
{'y': 'particular object', 'x': 'particular object'}
po2 = 'alpha'
ad.update(a=po2, b=po2, c=po2, d=po2, e=po2)
ad['x']
{'y': 'particular object', 'z': 'particular object'}
ad['a']
{'c': 'alpha', 'b': 'alpha', 'e': 'alpha', 'd': 'alpha'}
ad['b']
{'a': 'alpha', 'c': 'alpha', 'e': 'alpha', 'd': 'alpha'}
And since an Aliad instance is being returned,
ad['a']
{'c': 'alpha', 'b': 'alpha', 'e': 'alpha', 'd': 'alpha'}
ad['a']['e']
{'c': 'alpha', 'b': 'alpha', 'd': 'alpha'}
ad['a']['e']['b']
{'c': 'alpha', 'd': 'alpha'}
ad['a']['e']['b']['c']
{'d': 'alpha'}
ad['a']['e']['b']['d']
{'c': 'alpha'}
Is there an easier and cleaner way of doing this ? Is there example code
floating around that I might have a look at ?
Please show _any_ example code that does (tested ;-) _exactly_ what you want.
Then we can try for an easier and cleaner way ;-)
Hope the above helps to clarify requirements one way or another ;-)
Regards,
Bengt Richter
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Re: weird problem with os.chmod
On Sat, 12 Nov 2005 12:53:17 +0100, Fredrik Lundh [EMAIL PROTECTED] wrote: [...] int is designed for humans, not C programmers. humans tend to view e.g. 08 as a valid decimal number (*), not a ValueError. [...] /F *) unless you're living in sweden, in which case 08 is quite often used as an insult. I am always curious about languages, and considering my name, I think I'd like to know this definition ;-) Is it telephone-exchange-related? Or a police code for something? Can you say, delicately? (jag stavar daligt, men det gar bra pa Svenska om det ar omogligt at oversatta ;-) Regards, Bengt Richter -- http://mail.python.org/mailman/listinfo/python-list
Re: Tkinter and the re/sizing of columns in a grid
Normally, an entry widget requests horizontal space equal to the value of the width= option times the average character width of the font it displays. Setting it to 0 makes the entry request exactly enough width to show the string it contains. Making them sticky to the east and west sides of their areas make them grow to the size of the grid cell, if it is larger than their requested size. Making the grid column have nonzero weight means that if the user resizes the window to be wider, extra space will be given to the entry widgets. Perhaps this program does what you're looking for: #--- from Tkinter import * t = Tk() l1 = Label(t, text=String 1:) l2 = Label(t, text=String 2:) e1 = Entry(t, width=0); e1.insert(end, eggs); e1.focus() e2 = Entry(t, width=0); e2.insert(end, spam) l1.grid(row=0, column=0, sticky=w) l2.grid(row=1, column=0, sticky=w) e1.grid(row=0, column=1, sticky=ew) e2.grid(row=1, column=1, sticky=ew) t.grid_columnconfigure(1, weight=1, minsize=120) t.wm_title(entry width demo) t.mainloop() #--- pgp6Rij7z8hDA.pgp Description: PGP signature -- http://mail.python.org/mailman/listinfo/python-list
Re: directory listing
Shi Mu: Before all you were doing was defining a function with: import os def buildList( directory='c:\TEMP' ): dirs = [ ] listing = os.listdir(directory) for x in listing: x = os.path.join(directory, x) print x if os.path.isdir(x): dirs.append(x) return dirs when you python this file, it does not execute the function, it only defines it. Later Lundh told you to add: print buildList() to the end of the file. Not only does this execute buildList() but it also prints out the list dirs that buildList returns. So the first time it wasn't that print x wasn't printing anything, it was only that you weren't executing the function buildList(). If, at the end of the file, you put buildList() you will only see output values corresponding to the print x statement -- http://mail.python.org/mailman/listinfo/python-list
Re: how to present Python's OO feature in design?
Ben Sizer [EMAIL PROTECTED] wrote: I don't know if there are any tools that convert UML to Python code, dia2code http://dia2code.sourceforge.net Floriaa -- Einen Troll zu füttern ist das gleiche als würde man einen Haufen Hundescheisse sehen, absichtlich reinsteigen und sich dann beschweren. (Christian Schneider in [EMAIL PROTECTED]) -- http://mail.python.org/mailman/listinfo/python-list
Problem with __str__ if baseclass is list
#! /usr/bin/env python class A(list): def __init__(self, alist, n): list.__init__(self, alist) self.n = n def __str__(self): return 'AS(%s, %i)' % (list.__str__(self), self.n) def __repr__(self): return 'AR(%s, %i)' % (list.__repr__(self), self.n) a = A(['x', 'y'], 7) print 1, a print 2, repr(a) print 3, list.__str__(a) print 4, list.__repr__(a) The output is: 1 AS(AR(['x', 'y'], 7), 7) 2 AR(['x', 'y'], 7) 3 AR(['x', 'y'], 7) 4 ['x', 'y'] Why is list.__str__(a) == AR(['x', 'y'], 7)? Note: The problem goes away if list.__str__(a) is replaced with list.__repr__(self). -- http://mail.python.org/mailman/listinfo/python-list
XUL behavior in Python via XPCOM, Mozilla
I recently saw a claim that Mozilla XUL behaviors (normally scripted in Javascript) can (or perhaps will) be scriptable in Python. Also, other languages such as Java or Python are supported through XPCOM, said about Mozilla (from Luxor website). Yes, I know several ways to *generate* XUL from Python, and at least one way to use XUL to create interfaces for Python programs, but in this case, I'm talking about defining button action behavior in XUL by calling Python scripts. I know that Javascript is the preferred language, but I've seen several references to being able to do this in Python, including a claim that a release was targeted for early November (2005), to provide this. Now I can't find it again. Anyway, I was hoping someone on c.l.p / python.org would have a reliable reference on this. Thanks, Terry -- Terry Hancock ([EMAIL PROTECTED]) Anansi Spaceworks http://www.AnansiSpaceworks.com -- http://mail.python.org/mailman/listinfo/python-list
Re: SciPy python 2.4 wintel binaries
jelle schrieb: I dearly miss having the power of SciPy on my python 2.4 installation. The topic of SciPy python 2.4 wintel binaries has been discussed before on this list, but I haven't been able to find a compiled binary. If you really need SciPy, you should install Python 2.3 (Enthought Edition) in a separate directory as long as a Python 2.4 SciPy binary is not available. Python 2.3 EE comes with a bunch of useful additions, e.g. SciPy. -- http://mail.python.org/mailman/listinfo/python-list
Re: XUL behavior in Python via XPCOM, Mozilla
On Sat, 12 Nov 2005 14:25:51 -0600, Terry Hancock [EMAIL PROTECTED] wrote: I recently saw a claim that Mozilla XUL behaviors (normally scripted in Javascript) can (or perhaps will) be scriptable in Python. Also, other languages such as Java or Python are supported through XPCOM, said about Mozilla (from Luxor website). Yes, I know several ways to *generate* XUL from Python, and at least one way to use XUL to create interfaces for Python programs, but in this case, I'm talking about defining button action behavior in XUL by calling Python scripts. I know that Javascript is the preferred language, but I've seen several references to being able to do this in Python, including a claim that a release was targeted for early November (2005), to provide this. Now I can't find it again. Anyway, I was hoping someone on c.l.p / python.org would have a reliable reference on this. I'm not sure which claim you read, but perhaps it was in reference to PyXPCOM? http://aspn.activestate.com/ASPN/Downloads/Komodo/PyXPCOM/ I'm not quite sure if you are looking for the product itself or the announcement about it. Anyway, hope this helps. Jean-Paul -- http://mail.python.org/mailman/listinfo/python-list
Re: XUL behavior in Python via XPCOM, Mozilla
Terry Hancock wrote: I recently saw a claim that Mozilla XUL behaviors (normally scripted in Javascript) can (or perhaps will) be scriptable in Python. Also, other languages such as Java or Python are supported through XPCOM, said about Mozilla (from Luxor website). Yes, I know several ways to *generate* XUL from Python, and at least one way to use XUL to create interfaces for Python programs, but in this case, I'm talking about defining button action behavior in XUL by calling Python scripts. I know that Javascript is the preferred language, but I've seen several references to being able to do this in Python, including a claim that a release was targeted for early November (2005), to provide this. Now I can't find it again. Anyway, I was hoping someone on c.l.p / python.org would have a reliable reference on this. mozilla xul python + I feel lucky = http://weblogs.mozillazine.org/roadmap/archives/008865.html Python for XUL will be available in the Mozilla 1.9 milestone time frame, when the DOM_AGNOSTIC_BRANCH is landed some time this calendar year for sure /.../ The next major Firefox release based on the 1.9 milestone (Firefox 1.5 is based on the Mozilla 1.8 milestone) will include Mark's work -- but not a C-Python en- vironment by default. also see http://www.mozilla.org/roadmap/gecko-1.9-roadmap.html#Python_for_XUL (which says the same thing) /F -- http://mail.python.org/mailman/listinfo/python-list
Re: XUL behavior in Python via XPCOM, Mozilla
Terry Hancock wrote: I recently saw a claim that Mozilla XUL behaviors (normally scripted in Javascript) can (or perhaps will) be scriptable in Python. Also, other languages such as Java or Python are supported through XPCOM, said about Mozilla (from Luxor website). Yes, I know several ways to *generate* XUL from Python, and at least one way to use XUL to create interfaces for Python programs, but in this case, I'm talking about defining button action behavior in XUL by calling Python scripts. I know that Javascript is the preferred language, but I've seen several references to being able to do this in Python, including a claim that a release was targeted for early November (2005), to provide this. Now I can't find it again. Anyway, I was hoping someone on c.l.p / python.org would have a reliable reference on this. Thanks, Terry -- Terry Hancock ([EMAIL PROTECTED]) Anansi Spaceworks http://www.AnansiSpaceworks.com Nufox? http://trac.nunatak.com.au/projects/nufox -- http://mail.python.org/mailman/listinfo/python-list
Re: tutorial example
Max Erickson wrote: Not in python. For example, what would you call the following? def rsum(n, m): print n+m return n+m I would call it a python function with a side-effect. Colin W. In python a method is callable attached to an object. A function is a callable object constructed with a def statement. max -- http://mail.python.org/mailman/listinfo/python-list
Re: Proposal for adding symbols within Python
Pierre Barbier de Reuille [EMAIL PROTECTED] wrote: This proposal suggests to add symbols into Python. I still don't think symbol is particularly descriptive as a name; there are too many other things already in the language that might also be called a symbol. Symbols are objects whose representation within the code is more important than their actual value. An interesting Two symbols needs only to be equally-comparable. I believe it would be more useful to have enumerated types in Python, which would also allow values from the same type to be cmp() compared. Currently, there is no obvious way to define constants or states or whatever would be best represented by symbols. constants isn't a good equivalent here, since constants in most other languages are all about the name-to-value mapping, which you said was unimportant for this concept. Discussions on comp.lang.python shows at least half a dozen way to replace symbols. s/replace/implement/ Some use cases for symbols are : state of an object (i.e. for a file opened/closed/error) and unique objects (i.e. attributes names could be represented as symbols). That pretty much covers the common use cases. Nicely done. First, I think it would be best to have a syntax to represent symbols. I disagree. Namespaces would be fine, and would also make clear which values were related to each other; e.g. for your state of an object use case, it's useful to have all the states in one namespace, separate from unrelated states of other classes of objects. Adding some special char before the name is probably a good way to achieve that : $open, $close, ... are $ymbols. Counterproposal: FileState = SomeTypeDefiningStates( 'open', 'closed' ) thefile.state = FileState.open if thefile.state == FileState.closed: print File is closed So all that's needed here is the type SomeTypeDefiningStates, not a new syntax. One possible way to implement symbols is simply with integers resolved as much as possible at compile time. I believe all your requirements and motivations could be met with an Enum type in the language. Here's an implementation using a sequence of integers for the underlying values: First Class Enums in Python URL:http://aspn.activestate.com/ASPN/Cookbook/Python/Recipe/413486 An enumerated type would also allow values from that type to be compared with cmp() if their sequence was considered important. e.g. for object state, the normal sequence of states could be represented in the enumeration, and individual states compared to see if they are later that each other. If sequence was not considered important, of course, this feature would not get in the way. -- \ I put instant coffee in a microwave oven and almost went back | `\ in time. -- Steven Wright | _o__) | Ben Finney -- http://mail.python.org/mailman/listinfo/python-list
How to avoid f.close (no parens) bug?
plez send me -- http://mail.python.org/mailman/listinfo/python-list
Re: Proposal for adding symbols within Python
Pierre Barbier de Reuille [EMAIL PROTECTED] writes:
Please, note that I am entirely open for every points on this proposal
(which I do not dare yet to call PEP).
Abstract
This proposal suggests to add symbols into Python.
You're also proposing adding a syntax to generate symbols. If so, it's
an important distinction, as simply addig symbols is a lot more
straightforward than adding new syntax.
Symbols are objects whose representation within the code is more
important than their actual value. Two symbols needs only to be
equally-comparable. Also, symbols need to be hashable to use as keys of
dictionary (symbols are immutable objects).
The values returned by object() meet this criteria. You could write
LISPs gensym as:
gensym = object
As you've indicated, there are a number of ways to get such
objects. If all you want is symbols, all that really needs to happen
is that one of those ways be blessed by including an implementation in
the distribution.
In LISP : Symbols are introduced by '. 'open is a symbol.
No, they're not. '(a b c) is *not* a symbol, it's a list. Symbols in
LISP are just names. open is a symbol, but it's normally evaluated.
The ' is syntax that keeps the next expression from being evaluated,
so that 'open gets you the symbol rather than it's value. Since
you're trying to introduce syntax, I think it's important to get
existing practice in other languages right.
Proposal
First, I think it would be best to have a syntax to represent symbols.
That's half the proposal.
Adding some special char before the name is probably a good way to
achieve that : $open, $close, ... are $ymbols.
$ has bad associations for me - and for others that came from an
earlier P-language. Also, I feel that using a magic character to
introduce type information doesn't feel very Pythonic.
While you don't make it clear, it seems obvious that you intend that
if $open occurs twice in the same scope, it should refer to the same
symbol. So you're using the syntax for a dual purpose. $name checks to
see if the symbol name exists, and references that if so. If not, it
creates a new symbol and with that name. Having something that looks
like a variables that instantiates upon reference instead of raising
an exception seems like a bad idea.
On the range of symbols, I think they should be local to name space
(this point should be discussed as I see advantages and drawbacks for
both local and global symbols).
Agreed. Having one type that has different scoping rules than
everything else is definitely a bad idea.
There should be a way to go from strings to symbols and the other way
around. For that purpose, I propose:
assert symbol(opened) == $opened
assert str($opened) == opened
So the heart of your proposal seems to be twofold: The addition of
symbol as a type, and the syntax that has the lookup/create behavior
I described above.
Implementation
==
One possible way to implement symbols is simply with integers resolved
as much as possible at compile time.
What exactly are you proposing be resolved at compile time? How is
this better than using object, as illustratd above?
Suggested changes:
Provide a solid definition for the proposed builtin type symbol.
Something like:
symbol objects support two operations: is and equality
comparison. Two symbol objects compare equal if and only if
they are the same object, and symbol objects never compare
equal to any other type of object. The result of other
operations on a symbol object is undefined, and should raise
a TypeError exception.
symbol([value]) - creates a symbol object. Two distinct
calls to symbol will return two different symbol objects
unless the values passed to them as arguments are equal, in
which case they return the same symbol object. If symbol is
called without an argument, it returns a unique symbol.
I left the type of the value argument unspecified on purpose. Strings
are the obvious type, but I think it should be as unrestricted as
possible. The test on value is equality, not identity, because two
strings can be equal without being the same string, and we want that
case to give us the same symbol. I also added gensym-like behavior,
because it seemed useful. You could do without equality comparison,
but it seems like a nice thing to have.
Now propose a new syntax that means symbol, ala {} meaning dict
and [] meaning list. Don't use $name ( and ^ are also probably
bad, but not as; pretty much everything else but ? is already in
use). Python does seem to be moving away from this kind of thing,
though.
Personally, I think that the LISP quote mechanism would be a better
addition as a new syntax, as it would handle needs that have caused a
number of different proposals to be raised. It would require that
symbol know about the internals of the implementation so that ?name
and
Re: Can't uninstall wxPython
Justin wrote: I have two versions of wxPython installed on my Mac (OS X Tiger). One is version 2.6.1.0 and the other is version 2.6.0.0. I want to keep the newer version, but I can't seem to uninstall either one using the uninstall_wxPython.py script. When I run that script, I get this error message: $ sudo: uninstall_wxPython.py: command not found Is there any way I could delete one, or both, of these installations manually? For some reason, whenever I try to run a wxPython script, it uses the older version of wxPython and it doesn't always run correctly. Thanks in advance. If it has the x bit set you will have to do something like this: sudo ./uninstall_wxPython.py Otherwise pass python explicitly: sudo python uninstall_wxPython.py I think that it is going to wipe out all your wxPython installs...so you will need to reinstall the version you wanted. HTH, Robert -- http://mail.python.org/mailman/listinfo/python-list
Re: weird problem with os.chmod
Bengt Richter wrote: *) unless you're living in sweden, in which case 08 is quite often used as an insult. I am always curious about languages, and considering my name, I think I'd like to know this definition ;-) Is it telephone-exchange-related? it's the area code for Stockholm. I think you can figure the rest out yourself ;-) ... det gar bra pa Svenska om det ar omogligt at oversatta ;-) här finns lite mer bakgrund: http://susning.nu/Noll%E5tta http://susning.nu/Stockholmare /F -- http://mail.python.org/mailman/listinfo/python-list
Re: Proposal for adding symbols within Python
On Sat, 12 Nov 2005 16:52:12 -0500, Mike Meyer [EMAIL PROTECTED] wrote: [...] Personally, I think that the LISP quote mechanism would be a better addition as a new syntax, as it would handle needs that have caused a number of different proposals to be raised. It would require that symbol know about the internals of the implementation so that ?name and symbol(name) return the same object, and possibly exposing said object to the programmer. And this is why the distinction about how LISP acts is important. I wonder if the backquote could be deprecated and repurposed. It could typographically serve nicely as a lisp quote then. But in python, how would 'whatever be different from lambda:whatever ? (where of course whatever could be any expression parenthesized as necessary) Regards, Bengt Richter -- http://mail.python.org/mailman/listinfo/python-list
Re: XUL behavior in Python via XPCOM, Mozilla
On Sat, 12 Nov 2005 15:27:01 -0500 Jean-Paul Calderone [EMAIL PROTECTED] wrote: On Sat, 12 Nov 2005 14:25:51 -0600, Terry Hancock [EMAIL PROTECTED] wrote: I recently saw a claim that Mozilla XUL behaviors (normally scripted in Javascript) can (or perhaps will) be scriptable in Python. Also, other languages such as Java or Python are supported through XPCOM, said about Mozilla (from Luxor website). I'm not sure which claim you read, but perhaps it was in reference to PyXPCOM? http://aspn.activestate.com/ASPN/Downloads/Komodo/PyXPCO M/ I'm not quite sure if you are looking for the product itself or the announcement about it. Anyway, hope this helps. Really, I'm just fact-checking. It was the Brenden Eich article that Fredrik Lundh pointed to that I had found before, I was trying to recover it (turns out python xul mozilla + I feel lucky does NOT find it ;-), though it is on the first page, I admit). I wanted to get an idea of 1) When it would *really* be available 2) What developers or users would need to install in order to actually use a Python/XUL/Mozilla application. 3) Whether there was a version available that anyone here had tried, and what their experience was like. 4) Can you do this now, using PyXPCOM and the regular Mozilla/XUL? I'm refering to this in an article in press for Free Software Magazine, and I wanted to see just how close this really was to happening. If it's likely to be released in the next month or three, then it will probably come out before the article goes to press. It's not a huge point, but I hate to get stuff like this wrong. Cheers, Terry -- Terry Hancock ([EMAIL PROTECTED]) Anansi Spaceworks http://www.AnansiSpaceworks.com -- http://mail.python.org/mailman/listinfo/python-list
Re: XUL behavior in Python via XPCOM, Mozilla
On 12 Nov 2005 12:47:58 -0800 Devan L [EMAIL PROTECTED] wrote: Nufox? http://trac.nunatak.com.au/projects/nufox Nufox is a server-side tool to *generate* XUL from Python. Luxor http://luxor-xul.sourceforge.net/ is a XUL-interpreter written in Python, which therefore *replaces* Mozilla for XUL-based GUI applications. It scripts in Python or Java by default. But then there's the announcement at http://weblogs.mozillazine.org/roadmap/archives/008865.html by Brenden Eich that will use the PyXPCOM work by Mark Hammond to put python scripting capability into the Mozilla XUL engine, so that you can use script=application/x-python in order to do behavior scripting in Python from within XUL running on top of Mozilla. I was also a little foggy about the relationship between these components (which I hope I've just spelled out for the record). Thanks for the replies, Terry -- Terry Hancock ([EMAIL PROTECTED]) Anansi Spaceworks http://www.AnansiSpaceworks.com -- http://mail.python.org/mailman/listinfo/python-list
Re: UART parity setting as mark or space (using Pyserial???)
To provide feedback:
I have found the way how to control serial port parity bit on the Linux
(how to set the parity bit to the mark or space parity) within
Python using termios module.
With the help of:
http://www.lothosoft.ch/thomas/libmip/markspaceparity.php
===
import serial
import termios
import TERMIOS
ser=serial.Serial('/dev/ttyS0', 9600, 8, N, timeout=1)
iflag, oflag, cflag, lflag, ispeed, ospeed, cc = termios.tcgetattr(ser)
cflag |= PARENB | CMSPAR # To select SPACE parity
cflag = ~PARODD
cflag |= PARENB | CMSPAR | PARODD # to select MARK parity
termios.tcsetattr(ser, termios.TCSANOW, [iflag, oflag, cflag, lflag,
ispeed, ospeed, cc])
===
Using above mentioned it is possible to establish 9bit serial
communication according to the given protocol specifics. It is
necessary to control parity bit setting before sending each
communication byte.
Regards
Petr Jakes
--
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Re: gmpy 1.01 rc near... anybody wanna test
[EMAIL PROTECTED] wrote: What processor are you running? Drat, didn't see this before I left work. I'm fairly certain it was a Pentium 4, definitely 1.7GHz, Win2000 and Python 2.3. So I thought I would run the test again on my home computers, a Pentium 4 1.5 GHz WinXP Python 2.3 and a laptop with a Celeron 2.8 GHz WinXP Python 2.4. Here are the Celeron/Python2.4 numbers (and original test times) BF: 27.89 sec gen6 (31.92) CF: 0.203 sec gen9 (0.234) V: 5.062 sec gen9 (8.766) I only have Windows running on an old Pentium 3. It is easy for me to build a version that will running on almost any recent processor. I'm willing to try and override the CPU detection and make a processor specific build for you. I won't be able to test it, though. Thanks for the testing! Case -- http://mail.python.org/mailman/listinfo/python-list
Multikey Dict?
If I have a collection of dicts like:
john = {'id': 1, 'name': John Cleese, 'year': 1939}
graham = {'id': 2, 'name': Graham Chapman, 'year': 1941}
I could store all of them in a list. But for easy lookup, I might store
all these in a dict instead, like
people = {'1': john, '2': graham}
or maybe
people = {'John Cleese': john, 'Graham Chapman': graham}
or whatever key I might choose. Now, first of all, it seems a bit
annoying that I have to keep that redundant data in the second dict that
is already in the individual dicts within people. Secondly (and this is
my question), it is annoying that I have to choose one of several
unambiguous keys as a key.
I would like to be able to say:
people['1'].year
in some case and in other cases I want to say
people['John Cleese'].year
That is, sometimes I have the name at hand and would like to look up
data based on that. Other times, I have the ID at hand and would like to
look up data based on that instead.
Also, I would like if I didn't have to keep the key data both in the
dict of dicts and in the dicts :)
If I could just say to Python: john and graham (and ...) are all a part
of a superdict and either their id or their name can be used as keys.
Can I do that somehow?
/David
--
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ANN: askmgr
Hi all, I've just released a gui-based management utility for Active Spam Killer (ASK) installations. ASKmgr gives a quick and convenient way to manage one's ASK installation, including whitelists, ignorelists, blacklists, message queue and message log. (Fqr those not familiar, ASK is a powerful anti-spam system that works on whitelists, blacklists and a challenge-response system. It leaves Bayesian-based spamfilters in the dust, and has reduced my spam inflow from 4k+/week to 15/week. Posted on-topic here because both ASK and ASKmgr are written in Python. http://www.freenet.org.nz/askmgr2 -- Cheers aum -- http://mail.python.org/mailman/listinfo/python-list
Re: gmpy 1.01 rc near... anybody wanna test
[EMAIL PROTECTED] wrote: [EMAIL PROTECTED] wrote: What processor are you running? Drat, didn't see this before I left work. I'm fairly certain it was a Pentium 4, definitely 1.7GHz, Win2000 and Python 2.3. So I thought I would run the test again on my home computers, a Pentium 4 1.5 GHz WinXP Python 2.3 and a laptop with a Celeron 2.8 GHz WinXP Python 2.4. Here are the Celeron/Python2.4 numbers (and original test times) BF: 27.89 sec gen6 (31.92) CF: 0.203 sec gen9 (0.234) V: 5.062 sec gen9 (8.766) Oops, accidentally hit the send button. I didn't give you the results from my home desktop machine. And those are interesting. I did not intend for this test to be a benchmark, simply to make sure gmpy (and my library of Collatz Functions) were working properly. Can you imagine my shock at the reults of the closed form test: gmpy.version: 1.01 Closed form: Type12MH(k,i) Find ith, kth Generation Type [1,2] Mersenne Hailstone using the closed form equation 2**(6*((i-1)*9**(k-1)+(9**(k-1)-1)/2+1)-1)-1 2**5-1 generation: 1 0 seconds 2**29-1 generation: 2 0 seconds 2**245-1 generation: 3 0.015 seconds 2**2189-1 generation: 4 0 seconds 2**19685-1 generation: 5 0 seconds 2**177149-1 generation: 6 0.219 seconds 2**1594325-1 generation: 7 29.22 seconds 2**14348909-1 generation: 8 5295 seconds That's 88 minutes for the gen8 test alone (gen9 is still running). I was expecting a quarter second for the entire test! I realize that my office pc and my home pc are configured differently but there shouldn't be that much difference with the same version of Python and gmpy. At first I thought it was locking up, but it didn't have the symptoms of a lockup: menus still worked, Task manager didn't report not responding, and sure enough, it completed gen7 eventually. I finally figured it out, though. I had been toying with my Collatz Functions and made what I thought was a trivial change: Original function def Type12MH(k,i): Find ith, kth Generation Type [1,2] Mersenne Hailstone using the closed form equation Type12MH(k,i) k: generation i: member of generation returns Hailstone (a) if (k1) or (i1): return 0 a = (i-1)*9**(k-1) + (9**(k-1) - 1)/2 + 1 return 2**(6*a - 1) - 1 Now I know better than to allow coersion to mpz's to take place inside a loop, but this function doesn't loop. Nevertheless, I changed it to def Type12MH(k,i): Find ith, kth Generation Type [1,2] Mersenne Hailstone using the closed form equation Type12MH(k,i) k: generation i: member of generation returns Hailstone (a) ONE = gmpy.mpz(1) TWO = gmpy.mpz(2) SIX = gmpy.mpz(6) NIN = gmpy.mpz(9) if (k1) or (i1): return 0 i = gmpy.mpz(i) k = gmpy.mpz(k) # a = (i-1)*9**(k-1) + (9**(k-1) - 1)/2 + 1 # return 2**(6*a - 1) - 1 a = (i-ONE)*NIN**(k-ONE) + (NIN**(k-ONE) - ONE)/TWO + ONE return TWO**(SIX*a - ONE) - ONE And this was what is making my home desktop run so slow (at least with mega-bit sized numbers). As soon as I updated the Collatz Library, I got normal reults: BF: 37.11 sec gen6 CF: 0.563 sec gen9 V: 1.093 sec gen9 (Verified by setting it back to original.) Wow. Didn't realize things were that sensitive. Looks like I'll have to review a lot of my programs. I only have Windows running on an old Pentium 3. It is easy for me to build a version that will running on almost any recent processor. I'm willing to try and override the CPU detection and make a processor specific build for you. I won't be able to test it, though. Thanks for the testing! Case -- http://mail.python.org/mailman/listinfo/python-list
Re: Python obfuscation
On Sat, 12 Nov 2005 12:22:21 -0500, Mike Meyer wrote: And if instead you lose one customer because you've denied them their fair use rights, then your copy protection has lost you more in the form of a cost that you overlooked than all the costs you actually considered. In a competitive marketplace, why would I choose to buy DRMed software if there is a non-DRMed equivalent with the same functionality and equivalent cost? DRM is both an extra cost and a lower functionality applied to the software: an extra cost because if I can only run three simultaneous instances when I want four, then I need to pay more; lower functionality because things I may wish to do (like lock the original disk in the fireproof safe and install off a backup copy) may be impossible. If you are supplying to a non-competitive market, you may decide that you don't mind losing some sales. In non-competitive markets, the pressure to improve the ratio of functionality to cost is weak. [snip] Actually, obfuscation by itself has *no* benefit. If all you do is obfuscate the code, none of the pirates will ever notice - they'll just copy the code without ever trying to read it. It's the copy protection mechanisms you're trying to obfuscate that gains you the alleged benefit. I don't think you mean copy protection, as in preventing copies -- it is difficult for an application to prevent the OS from making physical copies, and by difficult I mean essentially impossible. Perhaps you mean access control, for example the software will only run for three people simultaneously. Once you provide a copy protection mechanism, obfuscation has some benefit, though the costs aren't clearly minimal, not if you're a cometent engineer. It's the benefits of the copy protection that I claim are insignificant. That's not quite true -- there may be instances where there is a real or perceived benefit from keeping the algorithms used secret: perhaps you have found a more efficient way to do something, or perhaps you just want to hide from your users just how bad your code really is, or perhaps you've conned^H^H^H^H convinced them to pay a premium price for reduced functionality and don't want them bypassing your access control mechanisms. The problem is, developers often have a ridiculously over-inflated opinion of the worth of their code, and the business people behind them even more so. Everybody[1] thinks that their two-bit Visual Basic calculator app is going to be the next Microsoft Windows and make them a fortune, but only if they keep the source code secret. Because so much code is secret, people fail to appreciate just how little innovation there really is in the IT industry, and imagine that just because they personally sweated blood for months writing the code, it must be valuable. Anyway, I think this is all a storm in a teacup. With the possible exception of game console software, I think the idea of shrink-wrapped software generally and software licencing particularly is a temporary aberration. In a decade, software obfuscation will only exist as a way for hackers to prove how clever they are, as in the Obfuscated C Contest. Until then, well, if you think you can a commercial advantage by annoying your customers, knock yourselves out. [1] By everyone I mean lots of people who should know better. -- Steven. -- http://mail.python.org/mailman/listinfo/python-list
Re: Iterator addition
On Thu, 9 Nov 2005, it was written: [EMAIL PROTECTED] (Alex Martelli) writes: Is there a good reason to not define iter1+iter2 to be the same as If you mean for *ALL* built-in types, such as generators, lists, files, dicts, etc, etc -- I'm not so sure. Hmm, there might also be __add__ operations on the objects, that would have to take precedence over iterator addition. Iterator addition itself would have to be a special kludge like figuring out from __cmp__, etc. Yeah, I guess the idea doesn't work out that well. Oh well. How about if we had some sort of special sort of iterator which did the right thing when things were added to it? like an iterable version of The Blob: class blob(object): def __init__(self, it=None): self.its = [] if (it != None): self.its.append(iter(it)) def __iter__(self): return self def next(self): try: return self.its[0].next() except StopIteration: # current iterator has run out! self.its.pop(0) return self.next() except IndexError: # no more iterators raise StopIteration def __add__(self, it): self.its.append(iter(it)) return self def __radd__(self, it): self.its.insert(0, iter(it)) Then we could do: all_lines = blob(file1) + file2 + file3 candidate_primes = blob((2,)) + (1+2*i for i in itertools.count(1)) Which, although not quite as neat, isn't entirely awful. Another option would be a new operator for chaining - let's use $, since that looks like the chain on the fouled anchor symbol used by navies etc: http://www.diggerhistory.info/images/badges-asstd/female-rels-navy.jpg Saying a $ b would be equivalent to chain(a, b), where chain (which could even be a builtin if you like) is defined: def chain(a, b): if (hasattr(a, __chain__)): return a.__chain__(b) elif (hasattr(b, __rchain__)): # optional return b.__rchain__(a) else: return itertools.chain(a, b) # or equivalent Whatever it is that itertools.chain or whatever returns would be modified to have a __chain__ method which behaved like blob.__add__ above. This then gets you: all_lines = file1 $ file2 $ file3 candidate_primes = (2,) $ (1+2*i for i in itertools.count(1)) And we're halfway to looking like perl already! Perhaps a more pythonic thing would be to define a then operator: all_lines = file1 then file2 then file3 candidate_primes = (2,) then (1+2*i for i in itertools.count(1)) That looks quite nice. The special method would be __then__, of course. tom -- if you can't beat them, build them -- http://mail.python.org/mailman/listinfo/python-list
Re: Multikey Dict?
If I could just say to Python: john and graham (and ...) are all a part of a superdict and either their id or their name can be used as keys. Can I do that somehow? Sure you can. There are two obvious ways to do this - enlist the aid of a Superdict (or similar) class to take care of the details. A simple implementation would be: class Superdict(object): def __init__(self, by_id, by_name): self.by_id = by_id self.by_name = by_name def __getitem__(self, value): if value.isdigit(): return self.by_id[value] else: return self.by_name[value] The alternative is to use some sort of database for storing these values. It doesn't really matter which (hell, you could even reinvent a relational wheel pretty simply in Python), as any DB worth its salt will do exactly what you need. Hope that helps, -Sam -- http://mail.python.org/mailman/listinfo/python-list
elementtree.ElemenTree barfs on my Safari Cookies file
Safari stores its cookies in XML format. Looking to try and add support for it to cookielib I started by first trying to parse it with Fredrik Lundh's elementtree package. It complained about an invalid token. Looking at the spot it indicated in the file, I found a non-ASCII, but (as far as I can tell) perfectly valid utf-8 string. I whittled the plist file down to what I've attached. With it I get e = elementtree.ElementTree.parse(Cookies.plist) Traceback (most recent call last): File stdin, line 1, in ? File /Users/skip/local/lib/python2.5/site-packages/elementtree/ElementTree.py, line 864, in parse tree.parse(source, parser) File /Users/skip/local/lib/python2.5/site-packages/elementtree/ElementTree.py, line 588, in parse parser.feed(data) File /Users/skip/local/lib/python2.5/site-packages/elementtree/ElementTree.py, line 1132, in feed self._parser.Parse(data, 0) xml.parsers.expat.ExpatError: not well-formed (invalid token): line 17, column 12 I had no trouble decoding that string as unicode. Any ideas what's wrong? Thx, Skip binfeFbX4goN0.bin Description: Binary data -- http://mail.python.org/mailman/listinfo/python-list
Re: derived / base class name conflicts
[EMAIL PROTECTED] a écrit :
Your suggestion ('_name' - implementation, 'name' - API)
This is not my convention, it's *the* (mostly agreed upon) Python
convention. Like 'self', or CONSTANT, or a whole lot of things in Python.
makes sense
as a convention between programmers that know a fair amount about each
other's classes before using them.
No need to know much. dir(modulename.ClassName) is enough.
I don't think it is reasonable in general to only subclass from base
classes you have studied the full API of, however.
Depends on your definition of studying the full API !-)
Now if your fear is to accidentally override something in the base
class, it's just a matter of:
print API:
print [name for name in dir(modulename.ClassName) \
if not name.startswith('_')]
print IMPLEMENTATION:
print [name for name in dir(modulename.ClassName) \
if not name.startswith('_')]
The double
underscore is a decent solution to my problem.
Possibly. It can also become a PITA. But it's you who know what your
code need !-)
I imagine it must be used a lot in domains where people are making
heavy use of third party python code.
I almost never used it (perhaps half-a-dozen times, and only in
frameworks abstract base classes), and rarely saw it in 3rd part source
code.
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Re: elementtree.ElemenTree barfs on my Safari Cookies file
skip I had no trouble decoding that string as unicode. *sigh* I need some new proofreading glasses. Should be ... string as utf-8. S -- http://mail.python.org/mailman/listinfo/python-list
Re: Multikey Dict?
David Rasmussen [EMAIL PROTECTED] writes:
If I have a collection of dicts like:
john = {'id': 1, 'name': John Cleese, 'year': 1939}
graham = {'id': 2, 'name': Graham Chapman, 'year': 1941}
I could store all of them in a list. But for easy lookup, I might
store all these in a dict instead, like
people = {'1': john, '2': graham}
or maybe
people = {'John Cleese': john, 'Graham Chapman': graham}
or whatever key I might choose. Now, first of all, it seems a bit
annoying that I have to keep that redundant data in the second dict
that is already in the individual dicts within people.
I don't see any redundant data in the dictionary. The *keys* might be
redundant, but that's because of the way you chose to store them.
Secondly (and this is my question), it is annoying that I have to
choose one of several unambiguous keys as a key.
So use them all. No big deal.
I would like to be able to say:
people['1'].year
in some case and in other cases I want to say
people['John Cleese'].year
This syntax looks like the values of the dictionary are objects, and
you're referencing attributes as opposed to looking up values in a
dictonary.
Also, I would like if I didn't have to keep the key data both in the
dict of dicts and in the dicts :)
Then don't. Dictionary keys are references objects. Make sure you
reference use the same object in both dictionaries.
If I could just say to Python: john and graham (and ...) are all a
part of a superdict and either their id or their name can be used as
keys.
Can I do that somehow?
It's easy enough to build your superdict class:
# Untested code
class SuperDict(dict):
def __init__(self, *keys):
dict.__init__(self)
self.keys = *keys
def __setitem__(self, key, item):
# Set the explicit key
dict.__setitem__(self, key, item)
# Set the implicit keys
for k in self.keys:
dict.__setitem__(self, item[k], item)
I think that gives you the behavior you want, except you have to use
the index syntax for both indices, instead of beinng able to use the
attribute syntax for the object returned by the dictionary.
mike
--
Mike Meyer [EMAIL PROTECTED] http://www.mired.org/home/mwm/
Independent WWW/Perforce/FreeBSD/Unix consultant, email for more information.
--
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Re: Multikey Dict?
David Rasmussen a écrit :
If I have a collection of dicts like:
john = {'id': 1, 'name': John Cleese, 'year': 1939}
graham = {'id': 2, 'name': Graham Chapman, 'year': 1941}
I could store all of them in a list. But for easy lookup, I might store
all these in a dict instead, like
people = {'1': john, '2': graham}
or maybe
people = {'John Cleese': john, 'Graham Chapman': graham}
You can use integers as keys in a dict. And building an index is not
that difficult:
peoples = [
{'id': 1, 'name': John Cleese, 'year': 1939},
{id': 2, 'name': Graham Chapman, 'year': 1941},
]
peoples_name_idx = dict((p['name'], p) for p in peoples)
peoples_id_idx = dict((p['id'], p) for p in peoples)
which generalize to:
def mk_index(index_field, records):
return dict((rec[index_field], rec) for rec in records)
(snip)
would like to be able to say:
people['1'].year
in some case and in other cases I want to say
people['John Cleese'].year
This should be:
people['John Cleese']['year']
(If you want transform your dicts to objects so you use dotted notation,
there are recipes for this in the Python Cookbook.)
If I could just say to Python: john and graham (and ...) are all a part
of a superdict and either their id or their name can be used as keys.
Can I do that somehow?
Writing a dict-like object is quite easy. Look for UserDict, or directly
subclass Dict.
Now, how could the superdict implementation decide which key to use ?
Here, you have a numeric 'id' and a string 'name', so you could test on
it in __getitem__, but what if you want to use 2 different string keys?
Computers are usually very bad at guessing, that's why we are
programming them.
My 2 cents
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Re: Multikey Dict?
Sam Pointon a écrit : If I could just say to Python: john and graham (and ...) are all a part of a superdict and either their id or their name can be used as keys. Can I do that somehow? Sure you can. There are two obvious ways to do this - enlist the aid of a Superdict (or similar) class to take care of the details. A simple implementation would be: class Superdict(object): def __init__(self, by_id, by_name): self.by_id = by_id self.by_name = by_name def __getitem__(self, value): if value.isdigit(): return self.by_id[value] else: return self.by_name[value] What if the OP now wants non numeric id fields ? -- http://mail.python.org/mailman/listinfo/python-list
[OT] Copyright [was Re: Python obfuscation]
On Fri, 11 Nov 2005 23:22:45 -0800, The Eternal Squire wrote: Without copyright, how could one possibly earn a living writing a novel? I don't know. How did William Shakespeare make a living from writing plays and sonnets and poems? How did Sir Walter Scott make a living from writing novels? How do chefs make a living from creating new recipes, and stand-up comedians from telling jokes? Perhaps there is no way to make a living from writing novels without copyright. There is no way to make a living from playing solitaire either -- should the government pass a law giving a legal monopoly on playing red queen on a black king to my granny, so that everyone playing that move has to pay her ten cents? That would make her old age so much more comfortable. If you object to my proposal, I can ask But without it, how could one possibly make a living playing solitaire? Do we care if novelists can make a living writing novels? Most of them don't anyway. The Stephen Kings, Tom Clancys and J.K. Rowlings are the exception, not the rule -- for every Terry Pratchett who has had to change banks because [he] filled the first one up, there are a hundred thousand who never make a living from writing at all. If you've been involved in writing novels, you will know that the real difference between an interesting idea and a great novel is usually a good editor. A good editor does maybe a quarter or a third of the intellectual labour of creating a novel -- not the grunt work of hitting typewriter keys and putting ink to paper, but the brain work of making sure that the story actually tells a story well. Why should the author get the monopoly and the editor nothing? How do editors make money without a monopoly granted by the government like copyright? How do magazine and newspaper writers make a living when they don't get the copyright on the things they write? These are all important questions, and you will notice I deliberately am not giving answers -- but they are also irrelevant because I didn't say that I was against copyright. What I asked was why the artificial rights of creators are given more importance than the natural rights of users. And I submit that many ISD's are only a single person burning with that one software idea of a lifetime, the equivalent of the Great American Novel. If their one software idea of a lifetime is as pointless, useless and just *bad* as the average would-be Great American Novel, then copyright or no copyright nobody will want their poxy code. Sourceforge is full of software projects, 90% of which go nowhere. The world is filled with millions of wanna-be poets, writers and creators whose sum total contribution to the artistic wealth of the world is negative. I'm not just using hyperbole. By poisoning the well with their garbage, they just make it that little bit harder for genuinely talented artists to be heard. Only 2% of books sell more than 5,000 copies, ever, and many wonderful books never get a second print-run because they just can't get people's attention. Despite this, people keep trying to write the Great American Novel. Creative artists will create, even if they would be economically better off washing dishes at Greasy Joe's Diner for a buck an hour. Michaelangelo didn't stop painting because he had no copyright protection. Are we to punish that impulse by denying that person a legal monopoly on that idea? Who's talking about *punishment*? The natural state of things is not copyright. No copyright is not punishing the author any more than no flying unicorns is punishing little girls with a fantasy for flying through the sky on the back of a horned horse. It is just the way things are. Copyright is a gift granted by the government, not the natural state of the world. When kings and emperors and presidents give commercial and economic gifts, like monopolies, they rarely are for the benefit of the majority. Lots of ideas have no legal monopoly. There is no legal monopoly on (say) good gardening skills, or the specific way of mixing the batter to make extra light and fluffy bread. Why should some ideas be privileged over others? Lack of copyright doesn't need to be defended, as it is the natural state of the world. Copyright is the special state which needs to be defended, and there is precious little evidence that copyright makes sense economically for *anyone*, author, publisher, readers or society as a whole. That's not to say that copyright isn't good for one or more of the above: I have my intuitions as to who copyright benefits. But my point is that there is a serious lack of evidence one way or the other, and what evidence there is suggests strongly that over-strong copyright laws (like we have now) are bad for *everyone*, and that weaker copyright (as in the early 20th century) would be better. I believe piracy is bad for everyone: the consumer, the writer, and the country as a whole. I don't oppose copyleft, but then, I don't oppose
tutorial example?????
OK...I have the following program i = 1 while i = 6: print 2 * i,' ', i = i + 1 print this is supposed to give you a "new"blank line after the program runs instead it just gives: 2 4 6 8 10 12 instead of: 2 4 6 8 10 12 to get the above return I have to type in "print" twice,this can't be right?..ANY SUGGESTIONS? i = 1 while i = 6: print 2 * i,' ', i = i + 1 print print Yahoo! FareChase - Search multiple travel sites in one click. -- http://mail.python.org/mailman/listinfo/python-list
Re: Proposal for adding symbols within Python
On Sat, 12 Nov 2005 18:59:39 +0100, Pierre Barbier de Reuille wrote: First, I think it would be best to have a syntax to represent symbols. Adding some special char before the name is probably a good way to achieve that : $open, $close, ... are $ymbols. I think your chances of convincing Guido to introduce new syntax is slim to none. (Not quite zero -- he did accept @ for decorators.) I think symbols should simply be an immutable object, one with state and limited or no behaviour, rather than a brand new syntactical element. Being an object, you can reference them in whatever namespace you define them in. Personally, I think rather than adding a new language feature (...slim to none...) there is more hope of getting something like this added to the standard library: http://aspn.activestate.com/ASPN/Cookbook/Python/Recipe/413486 -- Steven. -- http://mail.python.org/mailman/listinfo/python-list
Re: tutorial example
On Sat, 12 Nov 2005 13:42:37 +, Max Erickson wrote: Not in python. For example, what would you call the following? def rsum(n, m): print n+m return n+m In python a method is callable attached to an object. A function is a callable object constructed with a def statement. That's not *quite* right, because methods are also usually constructed with a def statement as well, and you can attach functions to objects by assignment: py def spam(n): ... return spam * n ... py class Viking: ... pass ... py eric_the_red = Viking() py eric_the_red.spam = spam py eric_the_red.spam(4) 'spam spam spam spam ' py type(eric_the_red.spam) type 'function' There is surely some technical definition that distinguishes between methods and functions, and between class, instance and static methods. At this level, the technical difference is not important. What is important is that, to a first approximation, functions and methods are the same thing. To a second approximation, functions belong to modules and methods belong to any other object. So in a module that looks like this: X = 1 def frob(x): Return the frobised value of x. return x class Parrot: def frob(self): Returns the frobised value of self. return self the top-level frob is a function and Parrot.frob is a method. Others have suggested that the difference between methods and functions is that methods do something and functions return a result. That's not quite true: both methods and functions can do something (something is known as a side-effect, and is *usually* but not always a Bad Idea), and both methods and functions *always* return an object, even if that object is just None. By convention, methods often (but not always) operate by side-effect: L = [1, 4, 2, 7] L.sort() But methods frequently return a value: s = Hello World s = s.upper() In fact even L.sort() returns a value: it returns None: who_cares = L.sort() # who_cares is now None; L is now sorted Languages such as Pascal have procedures, which don't return a value, and functions, which do. Python does not have procedures. -- Steven. -- http://mail.python.org/mailman/listinfo/python-list
Re: Iterator addition
Tom Anderson: And we're halfway to looking like perl already! Perhaps a more pythonic thing would be to define a then operator: all_lines = file1 then file2 then file3 Or a chain one: all_lines = file1 chain file2 chain file3 Bearophile -- http://mail.python.org/mailman/listinfo/python-list
Re: Hash map with multiple keys per value ?
Chris Stiles [EMAIL PROTECTED] wrote: ... alias insertion just be of the form x aliases to y rather than x names object XXX? In this case, strictly speaking there are no such thing as an 'object XXX', all the aliases are names for the object, each as important as each other. Fine, but, quite apart from names, IS there a Python object with a given identity, of which these aliases are names of? Or is that object something which does NOT exist as a Python object (in which case maybe calling it an entity, or some other name that's not used for specific purposes in Python, might be clearer!)...? def alias(self, x, y): dx = self.d.get(x,set([x])) dy = self.d.get(y,set([y])) self.d[x]=self.d[y]=dx+dy ^ Will that end up with two(many) references to the same set? [Though in any case I would be iterating over all values in the set). Yes, but it's buggy (doesn't modify the self.d[z] entries for all the z's which aren't either x nor y but alias either of them). Alex -- http://mail.python.org/mailman/listinfo/python-list
Re: Python obfuscation
Steven D'Aprano [EMAIL PROTECTED] wrote: In a competitive marketplace, why would I choose to buy DRMed software if there is a non-DRMed equivalent with the same functionality and equivalent cost? The only explanation I can think of is, their marketing must be AWEsome!-) Alex -- http://mail.python.org/mailman/listinfo/python-list
