Re: Python object overhead?
On 3/23/07, Bjoern Schliessmann [EMAIL PROTECTED] wrote: (Note that almost everything in Python is an object!) Could you tell me what in Python isn't an object? Are you counting old-style classes and instances as not objects? -- Felipe. -- http://mail.python.org/mailman/listinfo/python-list
Re: functions, classes, bound, unbound?
On 24 Mar 2007 20:24:36 -0700, 7stud [EMAIL PROTECTED] wrote: Here is some example code that produces an error: [snip] Why do people absolutely *love* to do weird and ugly things with Python? Contests apart, I don't see lots of people trying this kind of things on other (common) languages. Say with me: Python is powerful, but I'll use that power *only* for beautiful and straightforward code. Further reading: http://www.python.org/doc/Humor.html#zen -- Felipe. -- http://mail.python.org/mailman/listinfo/python-list
Re: Can I reverse eng a .pyc back to .py?
On 2/19/07, Steven W. Orr [EMAIL PROTECTED] wrote: The short story is that someone left, but before he left he checked in a .pyc and then both the directory was destroyed and the backups all got shredded (don't ask*). Is there anything that can be extracted? I looked on the web and the subject seems to get different answers, all old. Only for .pyc's of Python versions upto 2.3: http://packages.debian.org/unstable/python/decompyle -- Felipe. -- http://mail.python.org/mailman/listinfo/python-list
Re: help on packet format for tcp/ip programming
On 7 Feb 2007 19:14:13 -0800, [EMAIL PROTECTED] [EMAIL PROTECTED]
struct module pack and unpack will only work for fixed size buffer :
pack('1024sIL', buffer, count. offset) but the buffer size can vary
from one packet to the next :-(
Then send the size of the buffer before the buffer, so the recipient
can expect that many bytes.
--
Felipe.
--
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Re: maximum number of threads
On 1/10/07, Gabriel Genellina [EMAIL PROTECTED] wrote: At Wednesday 10/1/2007 04:38, Paul Sijben wrote: Does anyone know what it going on here and how I can ensure that I have all the threads I need? Simply you can't, as you can't have 1 open files at once. Computer resources are not infinite. Do you really need so many threads? Above a certain threshold, the program total execution time may increase very quickly. Maybe Stackless could help the OP? http://www.stackless.com/ -- Felipe. -- http://mail.python.org/mailman/listinfo/python-list
Re: maximum number of threads
On 1/10/07, Laurent Pointal [EMAIL PROTECTED] wrote: This is a system configurable limit (up to a maximum). See ulimit man pages. test ulimit -a to see what are the current limits, and try with ulimit -u 2000 to modify the maximum number of user process (AFAIK each thread use a process entry on Linux) I don't think it's only this. --- $ ulimit -a core file size (blocks, -c) 0 data seg size (kbytes, -d) unlimited max nice(-e) 20 file size (blocks, -f) unlimited pending signals (-i) unlimited max locked memory (kbytes, -l) unlimited max memory size (kbytes, -m) unlimited open files (-n) 1024 pipe size(512 bytes, -p) 8 POSIX message queues (bytes, -q) unlimited max rt priority (-r) unlimited stack size (kbytes, -s) 8192 cpu time (seconds, -t) unlimited max user processes (-u) unlimited virtual memory (kbytes, -v) unlimited file locks (-x) unlimited --- Well, unlimited number user processes. But: --- $ python test.py 50 100 150 200 250 300 350 Exception raised: can't start new thread Biggest number of threads: 382 --- The test.py script is attached. -- Felipe. from thread import start_new_thread from time import sleep def sleeper(): try: while 1: sleep(1) except: if running: raise def test(): global running n = 0 running = True try: while 1: start_new_thread(sleeper, ()) n += 1 if not (n % 50): print n except Exception, e: running = False print 'Exception raised:', e print 'Biggest number of threads:', n if __name__ == '__main__': test() -- http://mail.python.org/mailman/listinfo/python-list
Re: Determine an object is a subclass of another
On 9 Jan 2007 07:01:31 -0800, abcd [EMAIL PROTECTED] wrote: anyways, is there a way to check without having an instance of the class? In [1]: class A: ...: pass ...: In [2]: class B(A): ...: pass ...: In [3]: issubclass(B, A) Out[3]: True In [4]: isinstance(B(), B) Out[4]: True In [5]: isinstance(B(), A) Out[5]: True -- Felipe. -- http://mail.python.org/mailman/listinfo/python-list
Re: Suitability for long-running text processing?
On 1/8/07, tsuraan [EMAIL PROTECTED] wrote: [snip] The loop is deep enough that I always interrupt it once python's size is around 250 MB. Once the gc.collect() call is finished, python's size has not changed a bit. [snip] This has been tried under python 2.4.3 in gentoo linux and python 2.3 under OS X.3. Any suggestions/work arounds would be much appreciated. I just tried on my system (Python is using 2.9 MiB) a = ['a' * (1 20) for i in xrange(300)] (Python is using 304.1 MiB) del a (Python is using 2.9 MiB -- as before) And I didn't even need to tell the garbage collector to do its job. Some info: $ cat /etc/issue Ubuntu 6.10 \n \l $ uname -r 2.6.19-ck2 $ python -V Python 2.4.4c1 -- Felipe. -- http://mail.python.org/mailman/listinfo/python-list
Re: Suitability for long-running text processing?
On 1/8/07, tsuraan [EMAIL PROTECTED] wrote: I just tried on my system (Python is using 2.9 MiB) a = ['a' * (1 20) for i in xrange(300)] (Python is using 304.1 MiB) del a (Python is using 2.9 MiB -- as before) And I didn't even need to tell the garbage collector to do its job. Some info: It looks like the big difference between our two programs is that you have one huge string repeated 300 times, whereas I have thousands of four-character strings. Are small strings ever collected by python? In my test there are 300 strings of 1 MiB, not a huge string repeated. However: $ python Python 2.4.4c1 (#2, Oct 11 2006, 21:51:02) [GCC 4.1.2 20060928 (prerelease) (Ubuntu 4.1.1-13ubuntu5)] on linux2 Type help, copyright, credits or license for more information. # Python is using 2.7 MiB ... a = ['1234' for i in xrange(10 20)] # Python is using 42.9 MiB ... del a # Python is using 2.9 MiB With 10,485,760 strings of 4 chars, it still works as expected. -- Felipe. -- http://mail.python.org/mailman/listinfo/python-list
Re: Why less emphasis on private data?
On 07 Jan 2007 02:01:44 -0800, Paul Rubin http://phr.cx@nospam.invalid wrote: Dennis Lee Bieber [EMAIL PROTECTED] writes: __ (two leading underscores) results in name-mangling. This /may/ be used to specify private data, but is really more useful when one is designing with multiple super classes: Trouble with this is you can have two classes with the same name, perhaps because they were defined in different modules, and then the name mangling fails to tell them apart. What is the chance of having to inherit from two classes from different modules but with exactly the same name *and* the same instance variable name? Of course you're being very pessimistic or extremely unlucky. -- Felipe. -- http://mail.python.org/mailman/listinfo/python-list
Re: how to find the longst element list of lists
On 1/7/07, Michael M. [EMAIL PROTECTED] wrote: How to find the longst element list of lists? s1 = [q, e, d] s2 = [a, b] s3 = [a, b, c, d] s = [s1, s2, s3] s.sort(key=len, reverse=True) print s[0] is s3 print s[1] is s1 print s[2] is s2 sx1, sx2, sx3 = s print 'sx1:', sx1 print 'sx2:', sx2 print 'sx3:', sx3 -- Felipe. -- http://mail.python.org/mailman/listinfo/python-list
Re: Packaging up a Python/Twisted Matrix application...
On 1/4/07, Chaz Ginger [EMAIL PROTECTED] wrote: I have a rather large Python/Twisted Matrix application that will be run on Windows, Linux and perhaps Macs. I was wondering if there are any tools that can be used to create an installer that will bring in Python, Twisted Matrix, my application libraries and anything else I need? I haven't tried with Twisted, but I had success in using py2exe + Inno Setup on a program dependent on Python + ReportLab + pygtk. As both ReportLab and pygtk got even C extensions, I don't see why this setup wouldn't work with Twisted. -- Felipe. -- http://mail.python.org/mailman/listinfo/python-list
Re: A python library to convert RTF into PDF ?
On 3 Jan 2007 10:52:02 -0800, [EMAIL PROTECTED] [EMAIL PROTECTED] wrote: I have tried to convert them to tex using OpenOffice, but the result is ugly as hell. Why not use OO.org to convert DOC to PDF? It does so natively, IIRC. -- Felipe. -- http://mail.python.org/mailman/listinfo/python-list
Re: static object
On 1/3/07, meelab [EMAIL PROTECTED] wrote:
I am looking for a way to create a static object or a static class -
terms might be inappropriate - having for instance:
An example will speak better than me:
class Card(object):
__cards = {}
def __init__(self, number, suit):
self.number, self.suit = number, suit
def __new__(cls, number, suit):
try:
return cls.__cards[(number, suit)]
except KeyError:
obj = object.__new__(cls, number, suit)
cls.__cartas[(number, suit)] = obj
return obj
--
Felipe.
--
http://mail.python.org/mailman/listinfo/python-list
Re: Are all classes new-style classes in 2.4+?
On 31 Dec 2006 03:57:04 -0800, Isaac Rodriguez [EMAIL PROTECTED] wrote: I am using Python 2.4, and I was wondering if by default, all classes are assumed to be derived from object. This won't tell you advantages or disadvantages, but will show you that the default still is the old-style: class old: ... pass ... type(old()) type 'instance' dir(old()) ['__doc__', '__module__'] class new(object): ... pass ... type(new()) class '__main__.new' dir(new()) ['__class__', '__delattr__', '__dict__', '__doc__', '__getattribute__', '__hash__', '__init__', '__module__', '__new__', '__reduce__', '__reduce_ex__', '__repr__', '__setattr__', '__str__', '__weakref__'] In general, even if you don't understand the differences, it's better to use new-style (they're new ;-). Anyway, see http://effbot.org/pyref/new-style-and-classic-classes.htm for a little more information. -- Felipe. -- http://mail.python.org/mailman/listinfo/python-list
Re: A question about unicode() function
On 31 Dec 2006 05:20:10 -0800, JTree [EMAIL PROTECTED] wrote:
def funUrlFetch(url):
lambda url:urllib.urlopen(url).read()
This function only creates a lambda function (that is not used or
assigned anywhere), nothing more, nothing less. Thus, it returns None
(sort of void) no matter what is its argument. Probably you meant
something like
def funUrlFetch(url):
return urllib.urlopen(url).read()
or
funUrlFetch = lambda url:urllib.urlopen(url).read()
objUrl = raw_input('Enter the Url:')
content = funUrlFetch(objUrl)
content gets assigned None. Try putting print content before the unicode line.
content = unicode(content,gbk)
This, equivalent to unicode(None, gbk), leads to
TypeError: coercing to Unicode: need string or buffer, NoneType found
None's are not strings nor buffers, so unicode() complains.
See ya,
--
Felipe.
--
http://mail.python.org/mailman/listinfo/python-list
Re: BeautifulSoup vs. loose chars
On 26 Dec 2006 04:22:38 -0800, placid [EMAIL PROTECTED] wrote: So do you want to remove or replace them with amp; ? If you want to replace it try the following; I think he wants to replace them, but just the invalid ones. I.e., This this amp; that would become This amp; this amp; that No, i don't know how to do this efficiently. =/... I think some kind of regex could do it. -- Felipe. -- http://mail.python.org/mailman/listinfo/python-list
Re: Async callback in python
On 4 Dec 2006 20:18:22 -0800, Linan [EMAIL PROTECTED] wrote: 3, If not, where to get the real one(s)? After reading Calvin's mail, you may want to see http://twistedmatrix.com/ . It's an assynchronous library built around the concept of deferreds (think of callbacks). You may like it =). Cya, -- Felipe. -- http://mail.python.org/mailman/listinfo/python-list
Re: global name 'self' is not defined
On 2 Dec 2006 10:42:28 -0800, Evan [EMAIL PROTECTED] wrote: Why is it that the first call works fine, but the second tells me 'global name 'self' is not defined'? What I want is to have the dictionary 'estoc' available in my calling script. Well, you have not posted the code that is causing the problem, nowhere in your mail there's a reference to self. -- Felipe. -- http://mail.python.org/mailman/listinfo/python-list
Re: What are python closures realy like?
On 12/1/06, Karl Kofnarson [EMAIL PROTECTED] wrote: [snip] def fun_basket(f): common_var = [0] def f1(): print common_var[0] common_var[0]=1 def f2(): print common_var[0] common_var[0]=2 if f == 1: return f1 if f == 2: return f2 Everytime you call fun_basket you create another common_var. However, calling f1=fun_basket(1); f2 = fun_basket(2) and then f1(); f2() returns 0 and 0. Two calls to fun_basket, two different common_var's, two f1's and two f2's. Each f1/f2 pair have access to a different common_var, so it's working as expected. To work as you expected, fun_basket should be on the same block common_var is defined. -- Felipe. -- http://mail.python.org/mailman/listinfo/python-list
Re: Event driven server that wastes CPU when threaded doesn't
29 Oct 2006 14:18:02 -0800, Paul Rubin http://phr.cx@nospam.invalid: Nick Vatamaniuc [EMAIL PROTECTED] writes: The simplest solution is to change your system and put the DB on the same machine thus greatly reducing the time it takes for each DB query to complete (avoid the TCP stack completely). Since when do any db's let you avoid the TCP stack, even on the same machine? Since there are Unix sockets? A quick google: http://dev.mysql.com/doc/refman/5.0/en/multiple-unix-servers.html http://archives.postgresql.org/pgsql-hackers/1997-10/msg00568.php -- Felipe. -- http://mail.python.org/mailman/listinfo/python-list
Re: How to print a file in binary mode
22 Oct 2006 06:33:50 -0700, Lucas [EMAIL PROTECTED]: I known how to do it.read() return a string. so1) bytes = read(1) #read the file by bit.2) chrString= ord(bytes) #convert the string to ASCII.3) print numberToBinary(chrString) #convert the ASCII to Binary using my function.4) Loop[numberToBinary(ord(x)) for x in f.read()] ?-- Felipe. -- http://mail.python.org/mailman/listinfo/python-list
Re: PATCH: Speed up direct string concatenation by 20+%!
28 Sep 2006 19:07:23 -0700, Larry Hastings [EMAIL PROTECTED]: THE BENCHMARKS Benchmark 1: def add(a, b, c, ... t): return a + b + c + ... + t for i in range(1000): add(aaa, bbb, ccc, ..., ttt) [snip] What about a + b? Or a + b + c? Does it have a large overhead on small string concatenations? -- Felipe. -- http://mail.python.org/mailman/listinfo/python-list
Re: QOTW (was Re: does anybody earn a living programming in python?)
2006/9/26, Sybren Stuvel [EMAIL PROTECTED]: Aahz enlightened us with: Fredrik Lundh [EMAIL PROTECTED] wrote: well, if you're only watching mtv, it's easy to think that there's obviously not much demand for country singers, blues musicians, British hard rock bands, or melodic death metal acts. Any other votes for this being QOTW? +1 here +1 here, too -- Felipe. -- http://mail.python.org/mailman/listinfo/python-list
Re: does anybody earn a living programming in python?
2006/9/25, Robert Kern [EMAIL PROTECTED]: walterbyrd wrote: If so, I doubt there are many. I wonder why that is? Well I do. So do the other dozen or so developers at my company. We're looking to hire a few more, in fact. And there are also those ReportLab guys: www.reportlab.com -- Felipe. -- http://mail.python.org/mailman/listinfo/python-list
Re: What is the best way to get a web page?
24 Sep 2006 10:09:16 -0700, Rainy [EMAIL PROTECTED]: Functionally they are the same, but third line included in Firefox. Opera View Source command produces the same result as Python. [snip] It's better to compare with the result of a downloader-only (instead of a parser), like wget on Unix. That way you'll get exactly the same bytes (assuming the page is static). -- Felipe. -- http://mail.python.org/mailman/listinfo/python-list
Re: Decorator cllass hides docstring from doctest?
2006/9/21, Berthold Höllmann [EMAIL PROTECTED]: Saving the following code to a file and running the code through python does not give the expected error. disableling the @decor line leads to the expected error message. Is this a bug or an overseen feature? Try the new_decor class described below: class decor(object): ... def __init__(self, f): ... self.f = f ... def __call__(self, *args, **kw): ... return self.f(*args, **kw) ... class new_decor(object): ... def __init__(self, f): ... self.f = f ... self.__doc__ = f.__doc__ ... self.__name__ = f.__name__ ... def __call__(self, *args, **kw): ... return self.f(*args, **kw) ... def f(a, b): ... ''' ... f(1, 2) ... False ... f(2, 2) ... False ... ''' ... return a == b ... f.__doc__ '\n\t f(1, 2)\n\tFalse\n\t f(2, 2)\n\tFalse\n\t' decor(f).__doc__ == f.__doc__ False new_decor(f).__doc__ == f.__doc__ True -- Felipe. -- http://mail.python.org/mailman/listinfo/python-list
Re: How to stop an [Rpyc] server thread?
7 Sep 2006 23:38:08 -0700, Tal Einat [EMAIL PROTECTED]: I'm not an expert in socket programming, but I can't see the correlation between the listener socket being in timeout mode and a different behavior the other sockets.. Anyhow the main goal is being able to shut down the thread of the rpyc server, any other way is an appreciated suggestion. Now to the real issue. I've also had such weird problems with socket timeout in Python. The best workaround I found is to use select() to check for activity on the socket(s), and use select()'s timeout mechanism. So far, this has worked without a hitch on both WindowsXP and Solaris Sparc9 installations. Twisted[1] is the answer. I've never seen a better framework for using sockets, it's painless. I created two versions of the same protocol (both client and server), one using sockets + select, another using Twisted. The sockets version had 2x lines than the Twisted one and lots of bugs. Sockets may fail *anywhere* in your code, and Twisted takes care of all details for you[2]. Simply Sweet. Cheers, [1] http://www.twistedmatrix.com/ [2] Of couse this is just *one* advantage of the Twisted framework... PS.: No, I wasn't paid for this e-mail ;-) -- Felipe. -- http://mail.python.org/mailman/listinfo/python-list
Re: No ValueError for large exponents?
2006/9/6, Robin Becker [EMAIL PROTECTED]: enigmadude wrote: As many have heard, IronPython 1.0 was released. When I was looking through the listed differences between CPython and IronPython, the document mentioned that using large exponents such as 10 ** 735293857239475 will cause CPython to hang, whereas IronPython will raise a ValueError. Trying this on my own machine, it did indeed seem to cause CPython to hang. In cases such as this, should this be considered a bug in the CPython implementation that needs to be fixed? Or is there a reason for this, such as consideration of future changes and language definition vs language implementation, etc.? I suspect the hang may be python actually trying to work out the 1 followed by 735293857239475 zeroes. Perhaps IronPython has a forward looking algorithm that knows when to give up early. I think that IronPython does the same as the .Net runtime does. Look at boo's output: $ booish Welcome to booish, an interpreter for the boo programming language. Running boo 0.7.5.2013. The following builtin functions are available: dir(Type): lists the members of a type help(Type): prints detailed information about a type load(string): evals an external boo file globals(): returns the names of all variables known to the interpreter Enter boo code in the prompt below. 10**100 1E+100 10**100 ∞ 10**735293857239475 ERROR: Error reading from 'input3': 'Value too large or too small.'. (10**100).GetType() System.Double Well, it's a double on boo instead of a very long int as in Python. I don't know if in IronPython it's the same. -- Felipe. -- http://mail.python.org/mailman/listinfo/python-list
Re: ANN: Pocoo (bulletin board software) 0.1 beta released
10 Sep 2006 16:17:08 -0700, Paul Rubin http://phr.cx@nospam.invalid: So, I think it's not worth thinking about writing yet another BBS unless it can handle a Slashdot-sized load on a commodity PC. Python is slow. Psyco helps, but you should use C instead. And yes, I am kidding =) -- Felipe. -- http://mail.python.org/mailman/listinfo/python-list
Re: Best Middle Tier Architechure?
2006/9/7, Butternut Squash [EMAIL PROTECTED]: right now we are using c# and .net remoting in a way that just is not efficient. I want to rewrite a lot of what we do in python. I have seen XML-RPC and soap. Are there other options? It surely depends on what's going to be on the other sides. If everything is Python, you may use Twisted.Spread. If you have to communicate with different languages and plataforms, maybe CORBA helps. Well, I'm sure a lot of people know more options than I do here. -- Felipe. -- http://mail.python.org/mailman/listinfo/python-list
Re: best split tokens?
8 Sep 2006 13:41:48 -0700, Jay [EMAIL PROTECTED]: Let's say, for instance, that one was programming a spell checker or some other function where the contents of a string from a text-editor's text box needed to be split so that the resulting array has each word as an element. Is there a shortcut to do this and, if not, what's the best and most efficient token group for the split function to achieve this? your_string.split() -- Felipe. -- http://mail.python.org/mailman/listinfo/python-list
Re: Best Middle Tier Architechure?
2006/9/8, Butternut Squash [EMAIL PROTECTED]: I have to support multiple applications using different schema and databases. Would like to present as much as a unified interface as possible. I'd recomend CORBA as it supports multiple platforms and languages. SOAP and XML-RPC can be used as well, but I'm afraid performance can be a problem if a lot of calls are made or big/complex objects are transfered. -- Felipe. -- http://mail.python.org/mailman/listinfo/python-list
Re: convert loop to list comprehension
8 Sep 2006 17:37:02 -0700, [EMAIL PROTECTED] [EMAIL PROTECTED]: 1. Using an _ is an interesting way to use a throw-away variable. Never would I think of that ... but, then, I don't do Perl either :) It's a kind of convention. For example, Pylint complains for all variables you set and don't use unless its name is _. 2. Any reason for xrange() instead of range() It's faster. -- Felipe. -- http://mail.python.org/mailman/listinfo/python-list
Re: convert loop to list comprehension
08 Sep 2006 17:33:20 -0700, Paul Rubin http://phr.cx@nospam.invalid: [EMAIL PROTECTED] writes: print sum( ([i]*n for i,n in enumerate(seq)), []) Wow, I had no idea you could do that. After all the discussion about summing strings, I'm astonished. Why? You already had the answer: summing *strings*. Everything but strings can be summed by sum(). E.g.: Python 2.4.3 (#2, Apr 27 2006, 14:43:58) [GCC 4.0.3 (Ubuntu 4.0.3-1ubuntu5)] on linux2 Type help, copyright, credits or license for more information. class x(object): ... def __add__(self, other): ... return x(self.a + other.a) ... def __init__(self, a): ... self.a = a ... t = x(10) t.a 10 sum([t, t]) Traceback (most recent call last): File stdin, line 1, in ? TypeError: unsupported operand type(s) for +: 'int' and 'x' sum([t, t], t) __main__.x object at 0xb7d6752c _.a 30 sum([t, t], x(0)).a 20 sum([t, t]*1000, t).a 20010 -- Felipe. -- http://mail.python.org/mailman/listinfo/python-list
Re: python vs java
2006/9/7, Bruno Desthuilliers [EMAIL PROTECTED]: I don't think one could pretend writing a cross-platform application without testing it on all targeted platforms. E.g: while creating a free software, you may not have an Apple computer but you may want to be *possible* to run your program there. You don't test it, but you *think* it runs there. Not everybody has a spare MacOS X to test apps. Of course, if your software *needs* to run in some particular OS then you have to test on it. -- Felipe. -- http://mail.python.org/mailman/listinfo/python-list
Re: [ANN] IronPython 1.0 released today!
2006/9/5, Jim Hugunin [EMAIL PROTECTED]: I'm extremely happy to announce that we have released IronPython 1.0 today! http://www.codeplex.com/IronPython Does IronPython runs Twisted? -- Felipe. -- http://mail.python.org/mailman/listinfo/python-list
Re: IronPython 1.0 released today!
7 Sep 2006 16:34:56 -0700, Luis M. González [EMAIL PROTECTED]: People are already porting some of these libraries. Those that are written in pure python don't need to be ported, but those that rely on c extensions can be rewritten in c# or any other .NET language. Or in C that is P/Invoked from the CLR, although this option is somewhat less portable. See http://www.mono-project.com/Interop_with_Native_Libraries -- Felipe. -- http://mail.python.org/mailman/listinfo/python-list
Re: threading support in python
4 Sep 2006 19:19:24 -0700, Sandra-24 [EMAIL PROTECTED]: If there was a mod_dotnet I wouldn't be using CPython anymore. I guess you won't be using then: http://www.mono-project.com/Mod_mono -- Felipe. -- http://mail.python.org/mailman/listinfo/python-list
Re: Higher-level OpenGL modules
5 Sep 2006 03:44:47 -0700, Leon [EMAIL PROTECTED]: Greetings, Does anybody know of or is working on any python modules that allow for a direct but higher-level interface to OpenGL? For example, quick functions to draw lines, curves, and basic shapes; define hsb color mode; fill and stroke operations; easy loading of images, svg files, etc (much like the processing language - http://www.processing.org/reference/index.html). The closest thing I could find was devachan - http://www.cesaremarilungo.com/sw/devachan/, but its very limited. Any response would be greatly appreciated. Soya? I don't know if it fulfill your needs, though. http://home.gna.org/oomadness/en/soya/ -- Felipe. -- http://mail.python.org/mailman/listinfo/python-list
Re: Client-side TCP socket receiving Address already in use upon connect
2006/9/3, Alex Martelli [EMAIL PROTECTED]: Reflecting on the OP's use case, since all connections are forever being made to the same 16 servers, why not tweak thinks a bit to hold those connections open for longer periods of time, using a connection for many send/receive transactions instead of opening and closing such connections all of the time? That might well work better... Connecting to 16 differente servers per second gives a very poor performance, right? There's some overhead in creating TCP connections, even on fast networks and computers. Am I right? -- Felipe. -- http://mail.python.org/mailman/listinfo/python-list
Re: What do you want in a new web framework?
2006/8/30, Ben Finney [EMAIL PROTECTED]: re struct unicodedata decimal random logging Queue urlparse email operator cStringIO math cmath sets (merged to the language) itertools os + stat time tempfile glob Not that I use them all the time, but they are really useful and usually fulfill my needs. -- Felipe. -- http://mail.python.org/mailman/listinfo/python-list
Re: GC and security
2006/8/30, Les Schaffer [EMAIL PROTECTED]: is there a best practice way to do this? I'm not a cryptographer, but you should really try the function collect() inside the gc module. -- Felipe. -- http://mail.python.org/mailman/listinfo/python-list
Re: range of int() type.
23 Aug 2006 17:28:48 -0700, KraftDiner [EMAIL PROTECTED]: This is obvious... but how do I crop off the high order bits if necessary? a[0]0x ? min(a[0], 0x) ? -- Felipe. -- http://mail.python.org/mailman/listinfo/python-list
Re: List comparison help please
20 Aug 2006 14:47:14 -0700, Bucco [EMAIL PROTECTED]:
I am trying to compare a list of items to the list of files generated
by os.listdir. I am having trouble getting this to work and think I
may be going down the wrong path. Please let me know if hter is a
better way to do this. THis is what I have for my class so far:
Have you tried using sets?
import os
os.listdir('/')
['lost+found', 'var', 'etc', 'media', 'cdrom', 'bin', 'boot', 'dev',
'home', 'initrd', 'lib', 'mnt', 'opt', 'proc', 'root', 'sbin', 'srv',
'sys', 'tmp', 'usr', 'initrd.img', 'vmlinuz', 'windows',
'initrd.img.old', 'vmlinuz.old']
s = set(os.listdir('/'))
p = set(['opt', 'mnt', 'initrd', 'home', 'tmp', 'lib', 'media',
'boot', 'usr', 'var', 'proc', 'bin', 'sys', 'initrd.img.old', 'cdrom',
'lost+found', 'sbin', 'vmlinuz.old', 'windows'])
s - p
set(['dev', 'etc', 'vmlinuz', 'srv', 'root', 'initrd.img'])
--
Felipe.
--
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Re: Convert string to mathematical function
Em Ter, 2006-08-01 às 18:45 -0700, jeremito escreveu: I am extending python with C++ and need some help. I would like to convert a string to a mathematical function and then make this a C++ function. I may be wrong, but I don't think you can create new C++ functions on-the-fly. At least I had the impression that only VMs could do it (e.g. System.Reflection on .NET/Mono world and, of course, Python). My one idea (although I don't know how to implement it, I'm still new at this) is to pass to C++ a pointer to a (Python) function. Will this work? I think it will, but I can't tell you how =). -- Felipe. -- http://mail.python.org/mailman/listinfo/python-list
Re: math.pow(x,y)
Em Dom, 2006-06-11 às 11:19 -0700, fl1p-fl0p escreveu: import math math.pow(34564323, 456356) will give math range error. how can i force python to process huge integers without math range error? Any modules i can use possibly? 34564323**456356 ? -- Felipe. -- http://mail.python.org/mailman/listinfo/python-list
Re: how to get the length of a number
Em Dom, 2006-06-11 às 20:10 +, Stan Cook escreveu: Can anyone tell me how to get the length of a number. I know len(string) will get the length of a string, but it doesn't like len(int). I seem to remember something like %s string. I tried to set a variable = to %s int, but that doesn't work. Is there a function I've forgotten about to convert an integer to a string? To convert an integer i to a string: str(i) or %s % i To see how many decimal digits it has: import math math.ceil(math.log(i, 10)) -- Felipe. -- http://mail.python.org/mailman/listinfo/python-list
Re: how to get the length of a number
Em Dom, 2006-06-11 às 13:17 -0700, Saketh escreveu: Stan Cook wrote: Can anyone tell me how to get the length of a number. I know len(string) will get the length of a string, but it doesn't like len(int). I seem to remember something like %s string. I tried to set a variable = to %s int, but that doesn't work. Is there a function I've forgotten about to convert an integer to a string? Regards Stan Use str(int). Then use len(). For example, len(str(12345)) will give you 5. $ python2.4 -mtimeit -s 'x=12345' 'len(str(x))' 100 loops, best of 3: 1.33 usec per loop $ python2.4 -mtimeit -s 'x=12345;from math import ceil,log' 'ceil(log(x, 10))' 100 loops, best of 3: 1.54 usec per loop $ python2.4 -mtimeit -s 'x=12345**123' 'len(str(x))' 1000 loops, best of 3: 209 usec per loop $ python2.4 -mtimeit -s 'x=12345**123;from math import ceil,log' 'ceil(log(x, 10))' 100 loops, best of 3: 1.55 usec per loop $ python2.4 -mtimeit -s 'x=12345**1234' 'len(str(x))' 100 loops, best of 3: 19.2 msec per loop $ python2.4 -mtimeit -s 'x=12345**1234;from math import ceil,log' 'ceil(log(x, 10))' 100 loops, best of 3: 1.53 usec per loop -- Felipe. -- http://mail.python.org/mailman/listinfo/python-list
Re: how to get the length of a number
Em Dom, 2006-06-11 às 22:33 +0200, Sybren Stuvel escreveu: Felipe Almeida Lessa enlightened us with: To see how many decimal digits it has: import math math.ceil(math.log(i, 10)) That doesn't work properly. import math math.ceil(math.log(1, 10)) 4.0 math.ceil(math.log(10001, 10)) 5.0 But 1 certainly has as much digits as 10001. Hmmm, you're right. math.floor(math.log(x, 10)) + 1 -- Felipe. -- http://mail.python.org/mailman/listinfo/python-list
Re: Writing PNG with pure Python
Em Sex, 2006-06-09 às 12:30 -0400, Alan Isaac escreveu: It's your code, so you get to license it. But if you wish to solicit patches, a more Pythonic license is IMHO more likely to prove fruitful. Pythonic license? That's new to me. I can figure out what a Python-like license is, but I'm clueless about a Pythonic license. -- Felipe. -- http://mail.python.org/mailman/listinfo/python-list
Re: Killing a thread
Em Sex, 2006-06-09 às 13:54 -0700, Manish Marathe escreveu: On 6/9/06, Fredrik Lundh [EMAIL PROTECTED] wrote: Manish Marathe wrote: I am creating threads using my self defined class which inherits the threading.Thread class. I want to know how can I kill the threads which are being created by the object of my self defined class. you cannot kill a thread from the outside; you have to design your thread tasks so they can kill themselves, when asked to do that. Thanks for the reply. So can a thread listen to an event i.e. can we send an event to the thread indicating to kill itself. A plain simple boolean flag will certainly do the job. For example def run(self): self.running = True while self.running: blah() def stop(self): self.running = False -- Felipe. -- http://mail.python.org/mailman/listinfo/python-list
Re: 10GB XML Blows out Memory, Suggestions?
Em Ter, 2006-06-06 às 13:56 +, Paul McGuire escreveu: (just can't open it up like a text file) Who'll open a 10 GiB file anyway? -- Felipe. -- http://mail.python.org/mailman/listinfo/python-list
Re: Open Source Charting Tool
Em Sex, 2006-06-02 às 15:42 -0500, Larry Bates escreveu: ReportLab Graphics can do 2D and pie charts, but I don't think it does 3D charts yet. www.reporlab.org It does, but I'm not sure if the PNG backend is as good as the PDF one. -- Felipe. -- http://mail.python.org/mailman/listinfo/python-list
Re: Open Source Charting Tool
Em Sex, 2006-06-02 às 16:56 -0400, A.M escreveu: I can't browse to www.reporlab.org, but I found http://www.reportlab.com/ which has a commercial charting product. Is that what you referring to? ReportLab (the commercial bussiness thing on .com) is where the main developers of ReportLab (a library freely available on www.reporlab.org) work. So what you want really is .org, but apparently it's having problems right now. -- Felipe. -- http://mail.python.org/mailman/listinfo/python-list
Re: PEP-xxx: Unification of for statement and list-comp syntax
Em Dom, 2006-05-21 às 17:11 +0200, Heiko Wundram escreveu: for node in tree if node.haschildren(): do something with node as syntactic sugar for: for node in tree: if not node.haschildren(): continue do something with node Today you can archive the same effect (but not necessarily with the same performance) with: for node in (x for x in tree if x.haschildren()): do something with node But that's ugly... -- Felipe. -- http://mail.python.org/mailman/listinfo/python-list
Re: PEP-xxx: Unification of for statement and list-comp syntax
Em Dom, 2006-05-21 às 11:52 -0700, gangesmaster escreveu: Today you can archive the same effect (but not necessarily with the same performance) with: for node in (x for x in tree if x.haschildren()): do something with node true, but it has different semantic meanings I know, that's also why I don't oppose the PEP. -- Felipe. -- http://mail.python.org/mailman/listinfo/python-list
Re: calling upper() on a string, not working?
Em Ter, 2006-05-16 às 20:25 +, John Salerno escreveu:
it doesn't seem to work. The full code is below if it helps to understand.
Why doesn't it work? What does it do, what did you expect it to do?
''.join(set('hi'))
'ih'
''.join(set('HI'))
'IH'
''.join(set('hiHI'))
'ihIH'
''.join(set('hiHI'.upper()))
'IH'
--
Felipe.
--
http://mail.python.org/mailman/listinfo/python-list
Re: New tail recursion decorator
Em Ter, 2006-05-09 às 23:30 -0700, Kay Schluehr escreveu: http://aspn.activestate.com/ASPN/Cookbook/Python/Recipe/496691 Is it thread safe? -- Felipe. -- http://mail.python.org/mailman/listinfo/python-list
Re: NaN handling
Em Sex, 2006-05-05 às 16:37 -0400, Ivan Vinogradov escreveu:
This works to catch NaN on OSX and Linux:
# assuming x is a number
if x+1==x or x!=x:
#x is NaN
This works everywhere:
nan = float('nan')
.
.
.
if x == nan:
# x is not a number
--
Felipe.
--
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Re: problems when unpacking tuple ...
Em Sáb, 2006-04-22 às 09:21 -0700, harold escreveu: for line in sys.stdin : try : for a,b,c,d in line.split() : pass except ValueError , err : print line.split() raise err Try this: for a, b, c, d in sys.stdin: print a, b, c, d -- Felipe. -- http://mail.python.org/mailman/listinfo/python-list
Re: problems when unpacking tuple ...
Em Sáb, 2006-04-22 às 14:25 -0300, Felipe Almeida Lessa escreveu: Em Sáb, 2006-04-22 às 09:21 -0700, harold escreveu: for line in sys.stdin : try : for a,b,c,d in line.split() : pass except ValueError , err : print line.split() raise err Try this: for a, b, c, d in sys.stdin: print a, b, c, d Forget that. It was stupid. You should try this instead: for line in sys.stdin: a, b, c, d = line.split() -- Felipe. -- http://mail.python.org/mailman/listinfo/python-list
Re: Problem calling math.cos()
Em Sáb, 2006-04-22 às 15:14 -0400, Sambo escreveu: when I import it (electronics) in python.exe in windows2000 and try to use it, it croaks. ??? $ python2.4 Python 2.4.3 (#2, Mar 30 2006, 21:52:26) [GCC 4.0.3 (Debian 4.0.3-1)] on linux2 Type help, copyright, credits or license for more information. import math def ac_add_a_ph( amp1, ph1, amp2, ph2 ): ... amp3 = 0.0 ... ph3 = 0.0 ... ac1 = ( 0, 0j ) ... ac2 = ( 0, 0j ) ... ac3 = ( 0, 0j ) ... ac1 = complex( amp1 * math.cos( math.radians( ph1 ) ), amp1 * math.sin( math.radians( ph1 ) ) ) ... ac2 = complex( amp2 * math.cos( math.radians( ph2 ) ), amp2 * math.sin( math.radians( ph2 ) ) ) ... ac3 = ac1 + ac2 ... amp3 = math.abs( ac3 ) ... ph3 = math.atan( ac3.imag / ac3.real ) ... return [amp3, ph3] ... ac_add_a_ph(10, 0, 6, 45) Traceback (most recent call last): File stdin, line 1, in ? File stdin, line 10, in ac_add_a_ph AttributeError: 'module' object has no attribute 'abs' abs built-in function abs def ac_add_a_ph(amp1, ph1, amp2, ph2): ... ac1 = complex(amp1 * math.cos(math.radians(ph1)), amp1 * math.sin(math.radians(ph1))) ... ac2 = complex(amp2 * math.cos(math.radians(ph2)), amp2 * math.sin(math.radians(ph2))) ... ac3 = ac1 + ac2 ... ph3 = math.atan(ac3.imag / ac3.real) ... return [abs(amp3), ph3] ... ac_add_a_ph(10, 0, 6, 45) [14.86111751324192, 0.28951347254362308] So: --- import math def polar(rho, theta, theta_in_radians=False) Creates a complex number from its polar form. # Avoid repeating yourself by creating different functions if not theta_in_radians: theta = math.radians(theta) return complex(rho * math.cos(theta), rho * math.sin(theta)) def ac_add_a_ph(amp1, ph1, amp2, ph2): Add two complexes together from their polar form. # You don't have to initialize the variables with 0.0 and such. ac3 = polar(amp1, ph1) + polar(amp2, ph2) ph3 = math.atan(ac3.imag / ac3.real) return (abs(ac3), ph3) # Use a tuple in this case -- *But*, I encourage you using the complex numbers themselves instead of converting to and from over and over. HTH, -- Felipe. -- http://mail.python.org/mailman/listinfo/python-list
Re: Performance of Python 2.3 and 2.4
Em Dom, 2006-04-23 às 00:20 +0200, Michal Kwiatkowski escreveu:
Hi!
I was just wondering...
Probably there is another factor involved:
$ python2.3
Python 2.3.5 (#2, Mar 6 2006, 10:12:24)
[GCC 4.0.3 20060304 (prerelease) (Debian 4.0.2-10)] on linux2
Type help, copyright, credits or license for more information.
import timeit
timeit.Timer('2**1').timeit(1)
4.6463479995727539
timeit.Timer('112233445566778899 * 112233445566778899').timeit()
0.44853687286376953
$ python2.4
Python 2.4.3 (#2, Mar 30 2006, 21:52:26)
[GCC 4.0.3 (Debian 4.0.3-1)] on linux2
Type help, copyright, credits or license for more information.
import timeit
timeit.Timer('2**1').timeit(1)
4.9987671375274658
timeit.Timer('112233445566778899 * 112233445566778899').timeit()
0.36968302726745605
--
Felipe.
--
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Re: PyLint results?
Em Sex, 2006-04-21 às 13:49 -0400, Michael Yanowitz escreveu:
I ran the new pylint and my code and I had a few questions on why those
are warnings or what I can do to fix them:
You can ignore the warnings you don't like with the --disable-msg
option. Also, you can add a header to the file to apply a rule just to
it.
1) W: 0: Too many lines in module (1587)
Why is 1587 considered too many lines? Would there be necessarily be an
advantage to split it up into 2 or 3 files? Can I up the limit?
Because Python is terse, and this can be a really large module. Or not.
PyLint is not perfect, maybe you should disable this warning.
2) C: 0: Missing required attribute __revision__
What is this? Is that for CVS? I don't use CVS (we use SVN). I have not
seen any sample code which includes this tag yet. But if I include
__revision 1.0 somewhere in the code it will remove that warning?
Don't include the variable just to remove the warning -- disable it.
3) W:230:readDiscreteData: Using the global statement
What is wrong with using the global statement?
Your code can get unmaintainable if you abuse of it. If you really need
it and know how to use it well, disable the warning.
4) W:261:getDiscreteData: Catch Exception
What is wrong with that?
You may catch things you don't want to catch, like KeyboardInterrupt
exceptions.
5) R:547:readDiscreteData: Too many branches (28/12)
Python doesn't have the switch/case statements that C/C++ have. So I
could have a large block if/elif/else statements.
Is there any way to avoid that?
Only splitting the method into 2 or more parts. If that's not possible,
disable the warning.
6) R:722:waitDiscretes: Too many local variables (38/15)
That's new to me. What is wrong with too many local variables?
Can anything be done to improve that besides having too many globals?
The more local variables you have, the more difficult the code is to
read. Or you use less variables, or you split the method into 2 or more
parts, or you disable the warning.
7) W:933:sendStringToSocket: Redefining name 'nPortNumber' from outer scope
(line
What is wrong with using the same variable name in a function that is
used by its caller?
You are hiding something. For example, this code fails strangely (I know
this example isn't that good, but you get the idea):
files = glob('something/*')
for file in files:
# do_something
filename = do_something_with_the_name(file)
# do_something_more
contents = file(filename).read() # fails here
8) W:995:sendStringToSocket: Used builtin function 'map'
Is that a problem?
Sometimes it's slower than list comprehensions, sometimes it's less
legible than list comp. and IIRC GvR doesn't like it, but if you do,
disable the warning.
HTH,
--
Felipe.
--
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Re: String To Dict Problem
Em Sex, 2006-04-21 às 18:40 -0700, Clodoaldo Pinto escreveu:
Only a small problem when I try to evaluate this:
safe_eval('True')
Change
def visitName(self,node, **kw):
raise Unsafe_Source_Error(Strings must be quoted,
node.name, node)
To
otherNames = {
'True': True,
'False': False,
'None': None
}
def visitName(self, node, **kw):
name = node.name
try:
return self.__class__.otherNames[name]
except KeyError:
raise Unsafe_Source_Error(Strings must be quoted,
name, node)
--
Felipe.
--
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Re: Generate a sequence of random numbers that sum up to 1?
Em Sáb, 2006-04-22 às 03:16 +, Edward Elliott escreveu: If that level of accuracy matters, you might consider generating your rands as integers and then fp-dividing by the sum (or just store them as integers/fractions). Or using decimal module: http://docs.python.org/lib/module-decimal.html -- Felipe. -- http://mail.python.org/mailman/listinfo/python-list
Re: Method Call in Exception
Em Qua, 2006-04-19 às 16:54 -0700, mwt escreveu: This works when I try it, but I feel vaguely uneasy about putting method calls in exception blocks. What do you put in exception blocks?! So tell me, Brave Pythoneers, is this evil sorcery that I will end up regretting, or is it just plain good ol' Python magic? IMHO, the exception block in Python is used a lot in places where you could use an if-then-else, like your example that could be written as if internet_available(): [...] #doing some internet stuff else: alternate_method_that_doesnt_need_internet() So yes, I think there's no problem there. -- Felipe. -- http://mail.python.org/mailman/listinfo/python-list
Re: Uniquifying a list?
Em Ter, 2006-04-18 às 10:31 -0500, Tim Chase escreveu: Is there an obvious/pythonic way to remove duplicates from a list (resulting order doesn't matter, or can be sorted postfacto)? My first-pass hack was something of the form myList = [3,1,4,1,5,9,2,6,5,3,5] uniq = dict([k,None for k in myList).keys() or alternatively uniq = list(set(myList)) However, it seems like there's a fair bit of overhead here...creating a dictionary just to extract its keys, or creating a set, just to convert it back to a list. It feels like there's something obvious I'm missing here, but I can't put my finger on it. Your list with 11 elements (7 unique): $ python2.4 -mtimeit -s 'x = [3,1,4,1,5,9,2,6,5,3,5]' 'y = dict((k,None) for k in x).keys()' 10 loops, best of 3: 8.01 usec per loop $ python2.4 -mtimeit -s 'x = [3,1,4,1,5,9,2,6,5,3,5]' $'y = []\nfor i in x:\nif i not in y:\ny.append(i)' 10 loops, best of 3: 5.43 usec per loop $ python2.4 -mtimeit -s 'x = [3,1,4,1,5,9,2,6,5,3,5]' 'y = list(set(x))' 10 loops, best of 3: 3.57 usec per loop A list with 100 000 elements (1 000 unique): $ python2.4 -mtimeit -s 'x = range(1000) * 100' $'y = []\nfor i in x:\n if i not in y:\ny.append(i)' 10 loops, best of 3: 2.12 sec per loop $ python2.4 -mtimeit -s 'x = range(1000) * 100' 'y = dict((k,None) for k in x).keys()' 10 loops, best of 3: 32.2 msec per loop $ python2.4 -mtimeit -s 'x = range(1000) * 100' 'y = list(set(x))' 100 loops, best of 3: 6.09 msec per loop list(set(x)) is the clear winner with almost O(1) performance. *However*, can't you always use set or frozenset instead of converting back and forth? HTH, -- Felipe. -- http://mail.python.org/mailman/listinfo/python-list
Re: extracting a substring
Em Ter, 2006-04-18 às 17:25 -0700, [EMAIL PROTECTED] escreveu:
Hi,
I have a bunch of strings like
a53bc_531.txt
a53bc_2285.txt
...
a53bc_359.txt
and I want to extract the numbers 531, 2285, ...,359.
Some ways:
1) Regular expressions, as you said:
from re import compile
find = compile(a53bc_([1-9]*)\\.txt).findall
find('a53bc_531.txt\na53bc_2285.txt\na53bc_359.txt')
['531', '2285', '359']
2) Using ''.split:
[x.split('.')[0].split('_')[1] for x in 'a53bc_531.txt
\na53bc_2285.txt\na53bc_359.txt'.splitlines()]
['531', '2285', '359']
3) Using indexes (be careful!):
[x[6:-4] for x in 'a53bc_531.txt\na53bc_2285.txt
\na53bc_359.txt'.splitlines()]
['531', '2285', '359']
Measuring speeds:
$ python2.4 -m timeit -s 'from re import compile; find =
compile(a53bc_([1-9]*)\\.txt).findall; s = a53bc_531.txt
\na53bc_2285.txt\na53bc_359.txt' 'find(s)'
10 loops, best of 3: 3.03 usec per loop
$ python2.4 -m timeit -s 's = a53bc_531.txt\na53bc_2285.txt
\na53bc_359.txt\n[:-1]' [x.split('.')[0].split('_')[1] for x in
s.splitlines()]
10 loops, best of 3: 7.64 usec per loop
$ python2.4 -m timeit -s 's = a53bc_531.txt\na53bc_2285.txt
\na53bc_359.txt\n[:-1]' [x[6:-4] for x in s.splitlines()]
10 loops, best of 3: 2.47 usec per loop
$ python2.4 -m timeit -s 'from re import compile; find =
compile(a53bc_([1-9]*)\\.txt).findall; s = (a53bc_531.txt
\na53bc_2285.txt\na53bc_359.txt\n*1000)[:-1]' 'find(s)'
1000 loops, best of 3: 1.95 msec per loop
$ python2.4 -m timeit -s 's = (a53bc_531.txt\na53bc_2285.txt
\na53bc_359.txt\n * 1000)[:-1]' [x.split('.')[0].split('_')[1] for x
in s.splitlines()]
100 loops, best of 3: 6.51 msec per loop
$ python2.4 -m timeit -s 's = (a53bc_531.txt\na53bc_2285.txt
\na53bc_359.txt\n * 1000)[:-1]' [x[6:-4] for x in s.splitlines()]
1000 loops, best of 3: 1.53 msec per loop
Summary: using indexes is less powerful than regexps, but faster.
HTH,
--
Felipe.
--
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Re: filling today's date in a form
Em Dom, 2006-04-16 às 19:22 -0400, Kun escreveu: i have a form Which kind of form? Which toolkit? which takes in inputs for a mysql query. one of the inputs is 'date'. normally, a user has to manually enter a date, Enter the date in which kind of control? but i am wondering if there is a way to create a button which would automatically insert today's date in the date form field if the user chooses to use today's date. Almost 100% sure that there is, but I can't tell you if or how if you don't tell us how you are doing what you are doing. -- Felipe. -- http://mail.python.org/mailman/listinfo/python-list
Re: How to Convert a string into binary
Em Sáb, 2006-04-15 às 19:25 +, HNT20 escreveu: is there a way to convert a string into its binary representation of the ascii table.?? I'm very curious... why? And no, I don't have the answer. -- Felipe. -- http://mail.python.org/mailman/listinfo/python-list
Re: How to Convert a string into binary
Em Sáb, 2006-04-15 às 18:09 -0400, Terry Reedy escreveu: # given string s binchars = [] for c in s: binchars.append(a2b[ord(c)]) Faster: binchars = [a2b[ord(c)] for c in s] -- Felipe. -- http://mail.python.org/mailman/listinfo/python-list
Re: requestion regarding regular expression
Em Sex, 2006-04-14 às 07:47 -0700, BartlebyScrivener escreveu:
starts = [i for i, line in enumerate(lines) if
line.startswith('(defun')]
This line makes a list of integers. enumerate gives you a generator that
yields tuples consisting of (integer, object), and by i for i, line
you unpack the tuple into (i, line) and pick just i.
for i, start in starts:
Here you try to unpack the elements of the list starts into (i,
start), but as we saw above the list contains just i, so an exception
is raised.
I don't know what you want, but...
starts = [i, line for i, line in enumerate(lines) if
line.startswith('(defun')]
or
starts = [x for x in enumerate(lines) if x[1].startswith('(defun')]
...may (or may not) solve your problem.
--
Felipe.
--
http://mail.python.org/mailman/listinfo/python-list
Re: zlib and zip files
Em Sex, 2006-04-14 às 17:14 +0200, Jan Prochazka escreveu: Here is my module for parsing zip files: 1) Have you checked the source of Python's zipfile module? import struct, zlib class ZipHeaderEntry: name = '' offset = 0 uncomlen = 0 comlen = 0 2) You know that those variables are *class* vars, not instance vars, right? 3) I didn't read your code, but have you considered http://pyconstruct.sourceforge.net/ ? -- Felipe. -- http://mail.python.org/mailman/listinfo/python-list
Re: PEP 359: The make Statement
Em Sex, 2006-04-14 às 09:31 -0600, Steven Bethard escreveu: [1] Here's the code I used to test it. def make(callable, name, args, block_string): ... try: ... make_dict = callable.__make_dict__ ... except AttributeError: ... make_dict = dict ... block_dict = make_dict() ... exec block_string in block_dict ... return callable(name, args, block_dict) ... (snip) I think it would be nice not to put those and ... to make copy and paste easier. Okay, I know we can do .join(line[4:] for line in text), but that's just my humble opinion. -- Felipe. -- http://mail.python.org/mailman/listinfo/python-list
Re: instance variable weirdness
Em Sex, 2006-04-14 às 09:18 -0700, wietse escreveu: def __init__(self, name, collection=[]): Never, ever, use the default as a list. self.collection = collection This will just make a reference of self.collection to the collection argument. inst.collection.append(i) As list operations are done in place, you don't override the self.collection variable, and all instances end up by having the same list object. To solve your problem, change def __init__(self, name, collection=[]): BaseClass.__init__(self) self.name = name self.collection = collection # Will reuse the list to def __init__(self, name, collection=None): BaseClass.__init__(self) self.name = name if collection is None: collection = [] # Will create a new list on every instance self.collection = collection -- Felipe. -- http://mail.python.org/mailman/listinfo/python-list
Re: instance variable weirdness
Em Sex, 2006-04-14 às 13:30 -0300, Felipe Almeida Lessa escreveu: To solve your problem, change def __init__(self, name, collection=[]): BaseClass.__init__(self) self.name = name self.collection = collection # Will reuse the list to def __init__(self, name, collection=None): BaseClass.__init__(self) self.name = name if collection is None: collection = [] # Will create a new list on every instance self.collection = collection Or if None is valid in your context, do: __marker = object() def __init__(self, name, collection=__marker): BaseClass.__init__(self) self.name = name if collection is __marker: collection = [] # Will create a new list on every instance self.collection = collection -- Felipe. -- http://mail.python.org/mailman/listinfo/python-list
Re: instance variable weirdness
Em Sáb, 2006-04-15 às 04:03 +1000, Steven D'Aprano escreveu:
Sometimes you want the default to mutate each time it is used, for example
that is a good technique for caching a result:
def fact(n, _cache=[1, 1, 2]):
Iterative factorial with a cache.
try:
return _cache[n]
except IndexError:
start = len(_cache)
product = _cache[-1]
for i in range(start, n+1):
product *= i
_cache.append(product)
return product
I prefer using something like this for the general case:
def cached(function):
Decorator that caches the function result.
There's only one caveat: it doesn't work for keyword arguments.
cache = {}
def cached_function(*args):
This is going to be replaced below.
try:
return cache[args]
except KeyError:
cache[args] = function(*args)
return cache[args]
cached_function.__doc__ = function.__doc__
cached_function.__name__ = function.__name__
return cached_function
And for this special case, something like:
def fact(n):
Iterative factorial with a cache.
cache = fact.cache
try:
return cache[n]
except IndexError:
start = len(cache)
product = cache[-1]
for i in range(start, n+1):
product *= i
cache.append(product)
return product
fact.cache = [1, 1, 2]
This may be ugly, but it's less error prone. Also, we don't expose the
cache in the function's argument list.
--
Felipe.
--
http://mail.python.org/mailman/listinfo/python-list
Re: Writing backwards compatible code
Em Sex, 2006-04-14 às 13:28 -0500, Robert Kern escreveu: Steven D'Aprano wrote: I came across an interesting (as in the Chinese curse) problem today. I had to modify a piece of code using generator expressions written with Python 2.4 in mind to run under version 2.3, but I wanted the code to continue to use the generator expression if possible. Why? AFAICT, it really is just syntactic sugar. Very nice syntactic sugar, but not necessary at all. If you are going to have the ugly, syntactically bitter version in your code anyways, why clutter up your code even more trying to do both? Right. You can always use classes. -- Felipe. -- http://mail.python.org/mailman/listinfo/python-list
Re: skip item in list for loop
Em Sex, 2006-04-14 às 20:33 +0200, Diez B. Roggisch escreveu: def read_lines(inFile): fg = iter(inFile) for line in fg: if pmos4_highv in line: fg.next() else: yield line Just be aware that the fb.next() line can raise an StopIteration exception that would otherwise be caught by the for loop. If you have any resources that need to be cleaned up, try...finally is you friend. -- Felipe. -- http://mail.python.org/mailman/listinfo/python-list
Re: Writing backwards compatible code
Em Sex, 2006-04-14 às 13:37 -0500, Robert Kern escreveu: Felipe Almeida Lessa wrote: Em Sex, 2006-04-14 às 13:28 -0500, Robert Kern escreveu: Steven D'Aprano wrote: I came across an interesting (as in the Chinese curse) problem today. I had to modify a piece of code using generator expressions written with Python 2.4 in mind to run under version 2.3, but I wanted the code to continue to use the generator expression if possible. Why? AFAICT, it really is just syntactic sugar. Very nice syntactic sugar, but not necessary at all. If you are going to have the ugly, syntactically bitter version in your code anyways, why clutter up your code even more trying to do both? Right. You can always use classes. Well, I guess you could, but using actual generators would be much cleaner. That's the whole point around syntactic sugar: being cleaner, more concise, (sometimes) less error-prone and (less times) faster. -- Felipe. -- http://mail.python.org/mailman/listinfo/python-list
Re: Problem involving sets...
Em Sex, 2006-04-14 às 15:43 -0700, flamesrock escreveu:
Does anyone have a simple solution
$ python2.4
Python 2.4.3 (#2, Mar 30 2006, 21:52:26)
[GCC 4.0.3 (Debian 4.0.3-1)] on linux2
Type help, copyright, credits or license for more information.
l1 = [['c1',1],['c2',2],['c3',4]]
l2 = [['c1',1],['c2',2],['c4',4],['c3',3]]
print [tuple(x) for x in l1]
[('c1', 1), ('c2', 2), ('c3', 4)]
print [tuple(x) for x in l2]
[('c1', 1), ('c2', 2), ('c4', 4), ('c3', 3)]
s1 = frozenset(tuple(x) for x in l1)
s2 = frozenset(tuple(x) for x in l2)
print s1
frozenset([('c2', 2), ('c1', 1), ('c3', 4)])
print s2
frozenset([('c2', 2), ('c4', 4), ('c3', 3), ('c1', 1)])
print s2-s1
frozenset([('c4', 4), ('c3', 3)])
print [list(x) for x in s2-s1]
[['c4', 4], ['c3', 3]]
--
Felipe.
--
http://mail.python.org/mailman/listinfo/python-list
Re: Remove Whitespace
Em Sex, 2006-04-14 às 12:46 +1000, Steven D'Aprano escreveu: Why would you want to call in the heavy sledgehammer of regular expressions for cracking this peanut? And put heavy on that! $ python2.4 -mtimeit -s str = 'D c a V e r \ = d w o r d : 0 0 0 0 0 6 4 0' 'str.replace( , )' 10 loops, best of 3: 3.07 usec per loop $ python2.4 -mtimeit -s str = 'D c a V e r \ = d w o r d : 0 0 0 0 0 6 4 0' '.join(str.split())' 10 loops, best of 3: 4.16 usec per loop $ python2.4 -mtimeit -s from re import sub; str = 'D c a V e r \ = d w o r d : 0 0 0 0 0 6 4 0' 'sub(\\s, , str)' 1 loops, best of 3: 23.6 usec per loop $ calc 23.6 / 3.07 ~7.68729641693811074919 I couldn't be expressed better: Some people, when confronted with a problem, think I know, I'll use regular expressions. Now they have two problems. — Jamie Zawinski, in comp.lang.emacs -- Felipe. -- http://mail.python.org/mailman/listinfo/python-list
Re: PEP 359: The make Statement
Em Qui, 2006-04-13 às 23:17 -0400, Nicolas Fleury escreveu: The callable could have something like a __namespacetype__ that could be use instead of dict. That type would have to implement __setitem__. Or the namespace variable could be a list of tuples. -- Felipe. -- http://mail.python.org/mailman/listinfo/python-list
Re: list.clear() missing?!?
Em Sex, 2006-04-14 às 09:17 +0400, Sergei Organov escreveu: I, as a newcomer, don't have much trouble understanding the binding vs the assignment by themselves. What does somewhat confuse is dual role of the = operator, -- sometimes it means bind and other times it means assign, right? For me it seems that the language would be less error-prone and easier to grok if these two operations had different names/syntax (thinking about lisp let vs set), though it seems to be too drastic change even for Python3000. The = operator *always* binds. -- Felipe. -- http://mail.python.org/mailman/listinfo/python-list
Re: reading files in small chunks?
Em Sex, 2006-04-14 às 13:45 +0800, Rajesh Sathyamoorthy escreveu: I wanted to know why it is more efficient to read a file in smaller chunks ( using file() or open() )? It's more efficient in some cases, and worse on others. It also depends on how you implement the read loop. I won't elaborate too much here, there are loads of sites and books that talk about this topic. If this is not done, will this lead to errors in the data read or just results in slower performance? It doesn't corrupt anything, unless you have a buggy hardware. -- Felipe. -- http://mail.python.org/mailman/listinfo/python-list
Re: list.clear() missing?!?
Em Qua, 2006-04-12 às 12:40 -0700, Raymond Hettinger escreveu: * the existing alternatives are a bit perlish I love this argument =D! perlish... lol... Cheers, -- Felipe. -- http://mail.python.org/mailman/listinfo/python-list
Re: Why new Python 2.5 feature class C() return old-style class ?
Em Ter, 2006-04-11 às 06:49 -0700, looping escreveu: But in an other hand, I believe that new-style class are faster to instanciate (maybe I'm wrong...). $ python2.4 -m timeit -s 'class x: pass' 'x()' 100 loops, best of 3: 0.435 usec per loop $ python2.4 -m timeit -s 'class x(object): pass' 'x()' 100 loops, best of 3: 0.316 usec per loop -- Felipe. -- http://mail.python.org/mailman/listinfo/python-list
Re: Why new Python 2.5 feature class C() return old-style class ?
Em Ter, 2006-04-11 às 07:17 -0700, Aahz escreveu: Can, yes. But should it? The whole point of adding the () option to classes was to ease the learning process for newbies who don't understand why classes have a different syntax from functions. Having class C(): pass behave differently from class C: pass would be of no benefit for that purpose. Why should a newbie use an old-style class? -- Felipe. -- http://mail.python.org/mailman/listinfo/python-list
Re: list.clear() missing?!?
Em Ter, 2006-04-11 às 10:42 -0600, Steven Bethard escreveu: one of:: del lst[:] lst[:] = [] or if you don't need to modify the list in place, lst = [] Personally, I tend to go Fredrik's route and use the first. I love benchmarks, so as I was testing the options, I saw something very strange: $ python2.4 -mtimeit 'x = range(10); ' 100 loops, best of 3: 6.7 msec per loop $ python2.4 -mtimeit 'x = range(10); del x[:]' 100 loops, best of 3: 6.35 msec per loop $ python2.4 -mtimeit 'x = range(10); x[:] = []' 100 loops, best of 3: 6.36 msec per loop $ python2.4 -mtimeit 'x = range(10); del x' 100 loops, best of 3: 6.46 msec per loop Why the first benchmark is the slowest? I don't get it... could someone test this, too? Cheers, -- Felipe. -- http://mail.python.org/mailman/listinfo/python-list
Re: Manipulating sets from the 2.4 C API?
Em Ter, 2006-04-11 às 18:55 +0200, Martin v. Löwis escreveu: Dave Opstad wrote: If I want to handle sets should I just use a dictionary's keys and ignore the values, or is there some more explicit set support somewhere I'm not seeing? Indeed, there is. To create a new set, do PyObject_Call(PySet_Type, ); To, say, invoke the add method, do PyObject_CallMethod(s, add, O, o); I don't know much about the C API, but I'll ask anyway: the methods, say, PySet, would be included for clarity/brevity or for performance reasons? -- Felipe. -- http://mail.python.org/mailman/listinfo/python-list
Re: list.clear() missing?!?
Em Ter, 2006-04-11 às 17:56 +, John Salerno escreveu: Steven Bethard wrote: lst[:] = [] lst = [] What's the difference here? lst[:] = [] makes the specified slice become []. As we specified :, it transforms the entire list into []. lst = [] assigns the value [] to the variable lst, deleting any previous one. This might help: lst = range(10) id(lst), lst (-1210826356, [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]) lst[:] = [] id(lst), lst (-1210826356, []) lst = range(10) id(lst), lst (-1210844052, [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]) lst = [] id(lst), lst (-1210826420, []) You see? lst[:] removes all elements from the list that lst refers to, while lst = [] just creates a new list and discard the only one. The difference is, for example: lst = range(3) x = [lst, lst, lst] x [[0, 1, 2], [0, 1, 2], [0, 1, 2]] lst[:] = [] x [[], [], []] lst = range(3) x = [lst, lst, lst] x [[0, 1, 2], [0, 1, 2], [0, 1, 2]] lst = [] x [[0, 1, 2], [0, 1, 2], [0, 1, 2]] HTH, -- Felipe. -- http://mail.python.org/mailman/listinfo/python-list
Re: Memory limit to dict?
Em Ter, 2006-04-11 às 19:45 +0200, Peter Beattie escreveu:
I was wondering whether certain data structures in Python, e.g. dict,
might have limits as to the amount of memory they're allowed to take up.
Is there any documentation on that?
Why am I asking? I'm reading 3.6 GB worth of BLAST output files into a
nested dictionary structure (dict within dict ...). Looks something like
this:
{ GenomeID:
{ ProteinID:
{ GenomeID:
{ ProteinID, Score, PercentValue, EValue } } } }
I don't have the answer to your question and I'll make a new one: isn't
the overhead (performance and memory) of creating dicts too large to be
used in this scale?
I'm just speculating, but I *think* that using lists and objects may be
better.
My 2 cents,
--
Felipe.
--
http://mail.python.org/mailman/listinfo/python-list
Re: list.clear() missing?!?
Em Qua, 2006-04-12 às 11:36 +1000, Steven D'Aprano escreveu: On Tue, 11 Apr 2006 19:15:18 +0200, Martin v. Löwis wrote: Felipe Almeida Lessa wrote: I love benchmarks, so as I was testing the options, I saw something very strange: $ python2.4 -mtimeit 'x = range(10); ' 100 loops, best of 3: 6.7 msec per loop $ python2.4 -mtimeit 'x = range(10); del x[:]' 100 loops, best of 3: 6.35 msec per loop $ python2.4 -mtimeit 'x = range(10); x[:] = []' 100 loops, best of 3: 6.36 msec per loop $ python2.4 -mtimeit 'x = range(10); del x' 100 loops, best of 3: 6.46 msec per loop Why the first benchmark is the slowest? I don't get it... could someone test this, too? In the first benchmark, you need space for two lists: the old one and the new one; Er, what new list? I see only one list, x = range(10), which is merely created then nothing done to it. Have I missed something? He's talking about the garbage collector. Talking about the GC, do you want to see something *really* odd? $ python2.4 -mtimeit -s 'from gc import collect' 'collect(); x = range(10); ' 100 loops, best of 3: 13 msec per loop $ python2.4 -mtimeit -s 'from gc import collect' 'collect(); x = range(10); del x[:]' 100 loops, best of 3: 8.19 msec per loop $ python2.4 -mtimeit -s 'from gc import collect' 'collect(); x = range(10); x[:] = []' 100 loops, best of 3: 8.16 msec per loop $ python2.4 -mtimeit -s 'from gc import collect' 'collect(); x = range(10); del x' 100 loops, best of 3: 8.3 msec per loop But in this case I got the answer (I think): - When you explicitly delete the objects, the GC already know that it can be collected, so it just throw the objects away. - When we let the x variable continue to survive, the GC has to look at all the 11 objects to see if they can be collected -- just to see that it can't. Also, IIRC del x is slower than x = [] because removing a name from the namespace is more expensive than just assigning something else to it. Right? I understood Felipe to be asking, why does it take longer to just create a list, than it takes to create a list AND then do something to it? I see dead people... ;-) -- Felipe. -- http://mail.python.org/mailman/listinfo/python-list
Re: python + access + odbc + linux
Em Seg, 2006-04-10 às 10:38 -0500, Philippe Martin escreveu: I understand that access can be accessed through an ODBC driver under windows (instead of Jet). I am wondering if the same can be done under Linux. As far as I know, no. But there is that http://mdbtools.sourceforge.net/ that may help you, but when I tried I had limited success. Cheers, -- Felipe. -- http://mail.python.org/mailman/listinfo/python-list
Re: About classes and OOP in Python
Em Seg, 2006-04-10 às 07:19 -0700, fyhuang escreveu: class PythonClass: private foo = bar private var = 42 allow_readwrite( [ foo, var ] ) You are aware that foo and var would become class-variables, not instance-variables, right? But you can always do: class PythonClass(object): def __init__(self): self.__foo = bar foo = property(lambda self: self.__foo) And then: a = PythonClass() a.foo 'bar' a.foo = 'baz' Traceback (most recent call last): File stdin, line 1, in ? AttributeError: can't set attribute But you can also bypass this security: a._PythonClass__foo = 'baz' a.foo 'baz' But this was not a mistake, nobody mistakenly writes _PythonClass__. Or allow_read to only allow read-only access. Also there might be a way to implement custom getters and setters for those times you want to modify input or something: class PythonClass: def get foo(): return bar def set var( value ): var = value There's a PEP somewhere that proposes things like (same example I gave earlier): class PythonClass(object): def __init__(self): self.__foo = bar create property foo: def get(self): return self.__foo -- Felipe. -- http://mail.python.org/mailman/listinfo/python-list
Re: Is this code snippet pythonic
Em Seg, 2006-04-10 às 03:52 -0700, [EMAIL PROTECTED] escreveu: My Tead Lead my object counter code seen below is not pythonic As Peter said, you should really ask your Tead Lead, but what about: class E(object): Holds a class-wide counter incremented when it's instantiated. count = 0 def __init__(self): # One instance, increment the counter E.count += 1 def test(): Test the counter class E. e1 = E() assert e1.count == 1 print e1.count e2 = E() assert e2.count == 2 print e2.count e3 = E() assert e3.count == 3 print e3.count if __name__ == '__main__': test() -- Felipe. -- http://mail.python.org/mailman/listinfo/python-list
Re: how to make a generator use the last yielded value when it regains control
Em Seg, 2006-04-10 às 10:05 -0700, Lonnie Princehouse escreveu: I happen to think the recursive version is more elegant, but that's just me ;-) It may be elegant, but it's not efficient when you talk about Python. Method calls are expensive: $ python2.4 -mtimeit 'pass' 1000 loops, best of 3: 0.0585 usec per loop $ python2.4 -mtimeit -s 'def x(): pass' 'x()' 100 loops, best of 3: 0.291 usec per loop $ calc 0.291/0.0585 ~4.97435897435897435897 $ calc 0.291-0.0585 0.2325 This happens because of the dynamic nature of Python and its lack of tail call optimization. IOW, avoid recursive methods when possible (I usually write those for the first version of a method then rethink it using a non-recursive approach), specially if they are part of a hot spot. -- Felipe. -- http://mail.python.org/mailman/listinfo/python-list
Re: unboundlocalerror with cgi module
Em Seg, 2006-04-10 às 11:29 -0700, David Bear escreveu: However, the except block does not seem to catch the exception and an unboundlocalerror is thrown anyway. What am I missing? See http://docs.python.org/tut/node10.html : A try statement may have more than one except clause, to specify handlers for different exceptions. At most one handler will be executed. Handlers only handle exceptions that occur in the corresponding try clause, not in other handlers of the same try statement. An except clause may name multiple exceptions as a parenthesized tuple, for example: ... except (RuntimeError, TypeError, NameError): ... pass -- Felipe. -- http://mail.python.org/mailman/listinfo/python-list
