Python-URL! - weekly Python news and links (Apr 8)
QOTW: Those who show promise can advance to our Winter Improve Python to Expert program, for an additional fee, and, be given expert tutoring to help you gain our exemplary A.R.S.E./W.I.P.E certification which is guaranteed to attract certain types of employers by its name alone. - Paddy3118 http://groups.google.com/group/comp.lang.python/msg/f86e314251d94d96 Two new releases this week: * Python 3.1 alpha 2: http://mail.python.org/pipermail/python-list/2009-April/707817.html * and Python 2.6.2 candidate 1: http://mail.python.org/pipermail/python-list/2009-April/708214.html Dynamically adding new methods to a class hierarchy: http://groups.google.com/group/comp.lang.python/t/a6805cc39de3746a/ How to handle infinite generators (in the example, generating *all* prime numbers): http://groups.google.com/group/comp.lang.python/t/77cc9764f9d5a072/ Refactoring a giant class into smaller parts: http://groups.google.com/group/comp.lang.python/t/581d6b8dac0360d6/ People coming from static languages fear that Python code requires stronger unit tests - is that true? http://groups.google.com/group/comp.lang.python/t/8a3be7bb5ee1d1b4/ Synchronizing concurrent access to a dictionary: http://groups.google.com/group/comp.lang.python/t/d2156aa4aaf95bd5/ Can an object know whose attribute it is called upon? http://groups.google.com/group/comp.lang.python/t/1b43c60954e0a7a3/ Usually, returning different types based on input parameters is a bad idea: http://groups.google.com/group/comp.lang.python/t/b9fbef4368cf9981/ Everything Python-related you want is probably one or two clicks away in these pages: Python.org's Python Language Website is the traditional center of Pythonia http://www.python.org Notice especially the master FAQ http://www.python.org/doc/FAQ.html PythonWare complements the digest you're reading with the marvelous daily python url http://www.pythonware.com/daily Just beginning with Python? This page is a great place to start: http://wiki.python.org/moin/BeginnersGuide/Programmers The Python Papers aims to publish the efforts of Python enthusiats: http://pythonpapers.org/ The Python Magazine is a technical monthly devoted to Python: http://pythonmagazine.com Readers have recommended the Planet sites: http://planetpython.org http://planet.python.org comp.lang.python.announce announces new Python software. Be sure to scan this newsgroup weekly. http://groups.google.com/group/comp.lang.python.announce/topics Python411 indexes podcasts ... to help people learn Python ... Updates appear more-than-weekly: http://www.awaretek.com/python/index.html The Python Package Index catalogues packages. http://www.python.org/pypi/ The somewhat older Vaults of Parnassus ambitiously collects references to all sorts of Python resources. http://www.vex.net/~x/parnassus/ Much of Python's real work takes place on Special-Interest Group mailing lists http://www.python.org/sigs/ Python Success Stories--from air-traffic control to on-line match-making--can inspire you or decision-makers to whom you're subject with a vision of what the language makes practical. http://www.pythonology.com/success The Python Software Foundation (PSF) has replaced the Python Consortium as an independent nexus of activity. It has official responsibility for Python's development and maintenance. http://www.python.org/psf/ Among the ways you can support PSF is with a donation. http://www.python.org/psf/donations/ The Summary of Python Tracker Issues is an automatically generated report summarizing new bugs, closed ones, and patch submissions. http://search.gmane.org/?author=status%40bugs.python.orggroup=gmane.comp.python.develsort=date Although unmaintained since 2002, the Cetus collection of Python hyperlinks retains a few gems. http://www.cetus-links.org/oo_python.html Python FAQTS http://python.faqts.com/ The Cookbook is a collaborative effort to capture useful and interesting recipes. http://code.activestate.com/recipes/langs/python/ Many Python conferences around the world are in preparation. Watch this space for links to them. Among several Python-oriented RSS/RDF feeds available, see: http://www.python.org/channews.rdf For more, see: http://www.syndic8.com/feedlist.php?ShowMatch=pythonShowStatus=all The old Python To-Do List now lives principally in a SourceForge reincarnation. http://sourceforge.net/tracker/?atid=355470group_id=5470func=browse
Re: Anyone mannaged to access parallel port on windows xp?
Hi all, just would like to say that most of the parallel port preexistant code is usually blinking leds, which is the not the true reprsentation of the paralle port behaviour. Here one needs to think that data is coming out byte after byte. Now plz look out for the sequence to push data byte after byte. One pin to pulse(programatically) for a byte of data to come out is the Pin 0, strobe pin, then reset the same to push the next byte of data. Latare u r expected to send these data byte in the sequnce that the target board requirement. I have done this in c - dos based regards Prakash On Tue, Apr 7, 2009 at 12:09 PM, alejandro aleksanda...@brisiovonet.hrwrote: I have a switch that I should connect to the parallel port, but had no luck with it. Tha guy that made it for me told me that it would be easyer to connect via parallel instead the USB So did anyone have success? I only get suckess!! :-)) tryed giveio.sys but it doesn't wort (can't figure out what is it) -- http://mail.python.org/mailman/listinfo/python-list -- http://mail.python.org/mailman/listinfo/python-list
Re: Incomplete exception tracebacks when importing from zipped modules
En Thu, 02 Apr 2009 09:35:53 -0300, arve.knud...@gmail.com arve.knud...@gmail.com escribió: I can't seem to get complete tracebacks when modules imported from zip archives raise exceptions. [...] As you can see, the code for each stack entry is omitted. Is this normal?? A known problem, at least... You should be able to find it reported somewhere at http://bugs.python.org -- Gabriel Genellina -- http://mail.python.org/mailman/listinfo/python-list
Re: Injecting python function in an embedded python engine
En Mon, 06 Apr 2009 13:58:12 -0300, Roberto Fichera ker...@tekno-soft.it escribió: I've embedded python v2.6.x engine into my application without any problem. Now I would like to inject some additional functions after importing a python module. So, basically I'm importing a python module via PyImport_ImportModule() function. The python module is a simple set of functions and I would check if some functions does exist or not, than if doesn't I would add it from my C application. Checking if a function does exist or not isn't an issue, it works without any problem, my problem is only how to inject a new function in an already imported module. Easy (so I wonder whether I misunderstood your question): some_module.function_name = new_function_object or setattr(some_module, function_name, new_function_object) or use PyObject_SetAttr/PyObject_SetAttrString in C code. -- Gabriel Genellina -- http://mail.python.org/mailman/listinfo/python-list
RE: Scraping a web page
In message mailman.3480.1239112765.11746.python-l...@python.org, Support
Desk wrote:
You could do something like below to get the rendered page.
Import os
site = 'website.com'
X = os.popen('lynx --dump %s' % site).readlines()
I wonder how easy it would be to get the page image in SVG format? I believe
the Gecko HTML engine in Firefox already uses Cairo for its rendering, and
Cairo supports SVG as one of its surface types.
--
http://mail.python.org/mailman/listinfo/python-list
Re: Injecting python function in an embedded python engine
import os ch = os.system(import -window root temp.png) print ch after that no way to store the screen shot regards Prakash On Mon, Apr 6, 2009 at 10:28 PM, Roberto Fichera ker...@tekno-soft.itwrote: Hi All in the list, I've embedded python v2.6.x engine into my application without any problem. Now I would like to inject some additional functions after importing a python module. So, basically I'm importing a python module via PyImport_ImportModule() function. The python module is a simple set of functions and I would check if some functions does exist or not, than if doesn't I would add it from my C application. Checking if a function does exist or not isn't an issue, it works without any problem, my problem is only how to inject a new function in an already imported module. Thanks in advance, Roberto Fichera. -- http://mail.python.org/mailman/listinfo/python-list -- http://mail.python.org/mailman/listinfo/python-list
TypeError: object cannot be interpreted as an index
It started with this error message... TypeError: object cannot be
used as an index
foo = {}
someObject = someClass()
foo[someObject] = hello
Obviously, there are some known reasons why objects may not be
indexes, such as if they are not hashable (as in the case of lists).
However, I'm not getting that error message. I tested this out with
some minimal Python code, and the error did not occur. It only occurs
in my big codebase, not in a neat minimal example using a very small
class.
The type of this object is listed as 'instance'. My interpreter is
2.5.1
So I tried looking for more information inside types, and found
types.InstanceType.
Running help(types.InstanceType) gave me:
help(types.InstanceType)
hello
Traceback (most recent call last):
File stdin, line 1, in module
File /usr/local/python-2.5.1/lib/python2.5/site.py, line 345, in
__call__
import pydoc
File /usr/local/python-2.5.1/lib/python2.5/pydoc.py, line 56, in
module
from repr import Repr
ImportError: cannot import name Repr
There is a good chance that this object is build from C code,
instantiated through Swig. I'll have to do a bit more work to trace
back where the problem object is being created...
What, exactly, needs to be in place for an object to be a valid
dictionary key?
--
--
Tennessee Leeuwenburg
http://myownhat.blogspot.com/
Don't believe everything you think
--
http://mail.python.org/mailman/listinfo/python-list
Re: Q: Best book for teaching
On Apr 6, 10:37 am, grkunt...@gmail.com wrote: I am considering teaching an introduction to programming course for continuing education adults at a local community college. These would people with no programming experience, but I will require a reasonable facility with computers. What would be a good book to use as the text for the course? For an extremely gentle introduction, perhaps take a look at _Python Programming for the Absolute Beginner_ by Michael Dawson: http://www.amazon.com/Python-Programming-Absolute-Beginner-Michael/dp/1592000738 A coworker of mine recently bought this book, which is how I found out about it. Besides assuming no programming experience, it tries to stay interesting through the use of simple games for its examples (eventually building up to the use of the popular pygame library). The writing style is definitely more fun than academic. John -- http://mail.python.org/mailman/listinfo/python-list
Help with setting up Tkinter
import _tkinter import Tkinter Tkinter._test function _test at 0x0265D430 -- http://mail.python.org/mailman/listinfo/python-list
Help with setting up Tkinter
G'day All I was following the instructions (listed at bottom of post) from the PythonInfo Wiki which says to run three tests. I ran the tests and test 1 and 2 worked Test 3 gave me an error - function _test at 0x0265D430 can anyone help ??? Tks in advance Pete import _tkinter import Tkinter Tkinter._test function _test at 0x0265D430 _ Checking your Tkinter support A good way to systematically check whether your Tkinter support is working is the following. Enter an interactive Python interpreter in a shell on an X console. Step 1 - can _tkinter be imported? Try the following command at the Python prompt: import _tkinter # with underscore, and lowercase 't' * If it works, go to step 2. * If it fails with No module named _tkinter, your Python configuration needs to be modified to include this module (which is an extension module implemented in C). Do **not** edit Modules/Setup (it is out of date). You may have to install Tcl and Tk (when using RPM, install the -devel RPMs as well) and/or edit the setup.py script to point to the right locations where Tcl/Tk is installed. If you install Tcl/Tk in the default locations, simply rerunning make should build the _tkinter extension. * If it fails with an error from the dynamic linker, see above (for Unix, check for a header/library file mismatch; for Windows, check that the TCL/TK DLLs can be found). Step 2 - can Tkinter be imported? Try the following command at the Python prompt: import Tkinter # no underscore, uppercase 'T' * If it works, go to step 3. * If it fails with No module named Tkinter, your Python configuration need to be changed to include the directory that contains Tkinter.py in its default module search path. You have probably forgotten to define TKPATH in the Modules/Setup file. A temporary workaround would be to find that directory and add it to your PYTHONPATH environment variable. It is the subdirectory named lib-tk of the Python library directory (when using Python 1.4 or before, it is named tkinter). Step 3 - does Tkinter work? Try the following command at the Python prompt: Tkinter._test( ) # note underscore in _test( ) * This should pop up a small window with two buttons. Clicking the Quit button makes it go away and the command return. If this works, you're all set. (When running this test on Windows, from Python run in a MS-DOS console, the new window somehow often pops up *under* the console window. Move it aside or locate the Tk window in the Taskbar.) * If this doesn't work, study the error message you get; if you can't see how to fix the problem, ask for help. -- http://mail.python.org/mailman/listinfo/python-list
Re: Help with setting up Tkinter
On Wed, Apr 8, 2009 at 1:15 AM, Eclipse pnsm...@gmail.com wrote: import _tkinter import Tkinter Tkinter._test function _test at 0x0265D430 That last input line should be: Tkinter._test() Note the parens, which do matter (Python != Ruby/Smalltalk). Try again and see if you get an actual error. Cheers, Chris -- I have a blog: http://blog.rebertia.com -- http://mail.python.org/mailman/listinfo/python-list
Re: Help with setting up Tkinter
On Apr 8, 1:20 pm, Eclipse pnsm...@gmail.com wrote: G'day All I was following the instructions (listed at bottom of post) from the PythonInfo Wiki which says to run three tests. I ran the tests and test 1 and 2 worked Test 3 gave me an error - function _test at 0x0265D430 can anyone help ??? Tks in advance Pete import _tkinter import Tkinter Tkinter._test function _test at 0x0265D430 _ Checking your Tkinter support A good way to systematically check whether your Tkinter support is working is the following. Enter an interactive Python interpreter in a shell on an X console. Step 1 - can _tkinter be imported? Try the following command at the Python prompt: import _tkinter # with underscore, and lowercase 't' * If it works, go to step 2. * If it fails with No module named _tkinter, your Python configuration needs to be modified to include this module (which is an extension module implemented in C). Do **not** edit Modules/Setup (it is out of date). You may have to install Tcl and Tk (when using RPM, install the -devel RPMs as well) and/or edit the setup.py script to point to the right locations where Tcl/Tk is installed. If you install Tcl/Tk in the default locations, simply rerunning make should build the _tkinter extension. * If it fails with an error from the dynamic linker, see above (for Unix, check for a header/library file mismatch; for Windows, check that the TCL/TK DLLs can be found). Step 2 - can Tkinter be imported? Try the following command at the Python prompt: import Tkinter # no underscore, uppercase 'T' * If it works, go to step 3. * If it fails with No module named Tkinter, your Python configuration need to be changed to include the directory that contains Tkinter.py in its default module search path. You have probably forgotten to define TKPATH in the Modules/Setup file. A temporary workaround would be to find that directory and add it to your PYTHONPATH environment variable. It is the subdirectory named lib-tk of the Python library directory (when using Python 1.4 or before, it is named tkinter). Step 3 - does Tkinter work? Try the following command at the Python prompt: Tkinter._test( ) # note underscore in _test( ) * This should pop up a small window with two buttons. Clicking the Quit button makes it go away and the command return. If this works, you're all set. (When running this test on Windows, from Python run in a MS-DOS console, the new window somehow often pops up *under* the console window. Move it aside or locate the Tk window in the Taskbar.) * If this doesn't work, study the error message you get; if you can't see how to fix the problem, ask for help. Can you try Tkinter._test() instead of Tkinter._test Just Tkinter._test will go and hit its __repr__ code - i.e. representation I guess - which displays the function data instead of running actual function. -- http://mail.python.org/mailman/listinfo/python-list
Re: more fun with iterators (mux, demux)
On 07 Apr 2009 02:05:59 GMT Steven D'Aprano ste...@remove.this.cybersource.com.au wrote: The demuxer can't be an iterator, since it needs to run through the entire collection. Then your demuxer obviously cannot handle infinite sequences. def demux(it, n): collectors = [[] for i in xrange(n)] i = 0 for item in it: collectors[i].append(item) i = (i+1) % n return tuple([iter(x) for x in collectors]) But this one can: from collections import deque from itertools import cycle, izip, count, islice def mux(*iterables): for it in izip(*iterables): for item in it: yield item def demux(seq,n): it = iter(seq) Q = [deque() for i in xrange(n)] CQ = cycle(Q) def gen(D): for x,C in izip(it,CQ): C.appendleft(x) while D: yield D.pop() while D: yield D.pop() return map(gen,Q) def test(): a = count(10) b = count(20) c = count (30) x = demux(mux(a,b,c),3) for e in x: print list(islice(e,0,10)) if __name__=='__main__': test() P. -- http://mail.python.org/mailman/listinfo/python-list
Re: TypeError: object cannot be interpreted as an index
tleeuwenb...@gmail.com wrote:
It started with this error message... TypeError: object cannot be
used as an index
foo = {}
someObject = someClass()
foo[someObject] = hello
interpreted or used?
If the former, 'foo' may be a list rather than a dict, and someClass a
classic class:
class A: pass
...
{A(): 42}
{__main__.A instance at 0x2ac2a6d35bd8: 42}
[][A()]
Traceback (most recent call last):
File stdin, line 1, in module
TypeError: object cannot be interpreted as an index
To find out the actual the actual type of a classic class look into the
__class__ attribute:
type(A())
type 'instance'
A().__class__
class __main__.A at 0x2ac2a6d1e830
Peter
PS: Please cut and paste in the future.
--
http://mail.python.org/mailman/listinfo/python-list
Why does Python show the whole array?
Hello I'd like to go through a list of e-mail addresses, and extract those that belong to well-known ISP's. For some reason I can't figure out, Python shows the whole list instead of just e-mails that match: === script test = t...@gmail.com isp = [gmail.com, yahoo.com] for item in isp: if test.find(item): print item === output gmail.com yahoo.com === Any idea why I'm also getting yahoo.com? Thank you. -- http://mail.python.org/mailman/listinfo/python-list
Re: Why does Python show the whole array?
Gilles Ganault wrote: test = t...@gmail.com isp = [gmail.com, yahoo.com] for item in isp: if test.find(item): print item === output gmail.com yahoo.com === Any idea why I'm also getting yahoo.com? find() returns the index where it is found or -1 if it is not found. Both an index0 or a -1 evaluate to True when used as conditional expression. Uli -- Sator Laser GmbH Geschäftsführer: Thorsten Föcking, Amtsgericht Hamburg HR B62 932 -- http://mail.python.org/mailman/listinfo/python-list
Re: Why does Python show the whole array?
On Wed, 2009-04-08 at 12:01 +0200, Peter Otten wrote:
Gilles Ganault wrote:
I'd like to go through a list of e-mail addresses, and extract those
that belong to well-known ISP's. For some reason I can't figure out,
Python shows the whole list instead of just e-mails that match:
=== script
test = t...@gmail.com
isp = [gmail.com, yahoo.com]
for item in isp:
if test.find(item):
print item
=== output
gmail.com
yahoo.com
===
Any idea why I'm also getting yahoo.com?
Because str.find() returns the position of the search string if found and -1
if it is not found:
abc.find(bc)
1
abc.find(ab)
0
abc.find(x)
-1
Use
if test.find(item) != -1: ...
or
if item in test: ...
to make your example work.
Or you could also use the .endswith() method
if test[test.find('@')+1:].endswith(item):
--
http://mail.python.org/mailman/listinfo/python-list
Re: Why does Python show the whole array?
Gilles Ganault nos...@nospam.com writes: I'd like to go through a list of e-mail addresses, and extract those that belong to well-known ISP's. For some reason I can't figure out, Python shows the whole list instead of just e-mails that match: === script test = t...@gmail.com isp = [gmail.com, yahoo.com] for item in isp: if test.find(item): print item === output gmail.com yahoo.com === Any idea why I'm also getting yahoo.com? You've had answers on the “why” question. Here's a suggestion for a better way that doesn't involve ‘find’: known_domains = [example.com, example.org] test_address = t...@example.com for domain in known_domains: ... if test_address.endswith(@ + domain): ... print domain ... example.com If all you want is a boolean “do any of these domains match the address”, it's quicker and simpler to feed an iterator to ‘any’ (first introduced in Python 2.5), which short-cuts by exiting on the first item that produces a True result: known_domains = [example.com, example.org] test_address = t...@example.com any(test_address.endswith(@ + domain) for domain in known_domains) True test_address = tin...@example.net any(test_address.endswith(@ + domain) for domain in known_domains) False -- \ “For my birthday I got a humidifier and a de-humidifier. I put | `\ them in the same room and let them fight it out.” —Steven Wright | _o__) | Ben Finney -- http://mail.python.org/mailman/listinfo/python-list
Re: How to go about. On read/write locks
Carl Banks pavlovevide...@gmail.com (CB) wrote: CB On Apr 6, 2:23 pm, Diez B. Roggisch de...@nospam.web.de wrote: This is a classical synchronization problem with a classical solution: You treat the readers as a group, and the writers individually. So you have a write lock that each writer has to acquire and release, but it is acquired only by the first reader and released by the last one. Therefore you need a counter of the number of readers, and manipulations of this counter must be protected by another lock. I was going to suggest a similar approach but refused to because of a problem I see with your code as well - if the readers are reading very fast (the OP didn't state what his actual application is, so it might not be a consumer-producer scheme which I don't think a dict would be the natural choice anyway) they can block the writer from writing alltogether. CB You could implement some kind of fair ordering where whoever requests CB a lock first is guaranteed to get it first, but I can't think of a way CB to do that without requiring all readers to acquire two locks. The original implementation (with writers starvation) comes from [1]. They also describe a solution where witers have priority, but it needs 5 semaphores and 2 counters (one for writers and one for readers). It can cause starvation for readers, however. For the OP this wouldn't be a problem because writers are rare in his situation. However, I found a solution [2] with just one additional counter for the number of writers and no additional semaphores. The manipulations of the writers counter are also protected by the same mutex. This solution is fair for both readers and writers. Translated in Python this would be: # from threading import Lock mutex = Lock() writelock = Lock() numreaders = 0 numwriters = 0 # # Reader code: mutex.acquire() if numwriters 0 or numreaders == 0: mutex.release() writelock.acquire() mutex.acquire() numreaders += 1 mutex.release() ## critical section for reader mutex.acquire() numreaders -= 1 if numreaders == 0: writelock.release() mutex.release() # # Writer code: mutex.acquire() numwriters += 1 mutex.release() writelock.acquire() ## critical section for writer mutex.acquire() numwriters -= 1 mutex.release() writelock.release() # I am going to put this in a class, with a context manager so that it can be use with the 'with' statement like the normal locks. I also found a solution with no additional counters but an additional semaphore, but I found it only in lecture notes [3,4]; I couldn't find any scientific publications about it. So I don't know for sure if it is correct, fair etc. [1] P. J. Courtois , F. Heymans , D. L. Parnas, Concurrent control with “readers” and “writers”, Communications of the ACM, v.14 n.10, p.667-668, Oct. 1971 [2] Jalal Kawash, Process Synchronization with Readers and Writers Revisited Journal of Computing and Information Technology - CIT 13, 2005, 1, 43–51 [3] http://pages.cs.wisc.edu/~haryadi/537/slides/lec18-semaphores.ppt [4] http://vorlon.case.edu/~jrh23/338/HW3.pdf -- Piet van Oostrum p...@cs.uu.nl URL: http://pietvanoostrum.com [PGP 8DAE142BE17999C4] Private email: p...@vanoostrum.org -- http://mail.python.org/mailman/listinfo/python-list
Re: Why does Python show the whole array?
Gilles Ganault wrote: Hello I'd like to go through a list of e-mail addresses, and extract those that belong to well-known ISP's. For some reason I can't figure out, Python shows the whole list instead of just e-mails that match: === script test = t...@gmail.com isp = [gmail.com, yahoo.com] for item in isp: if test.find(item): print item === output gmail.com yahoo.com === Any idea why I'm also getting yahoo.com? Thank you. Look up the definition of string.find(). It returns a -1 for failure, not 0. So your test should presumably be if test.find(item) != -1: -- http://mail.python.org/mailman/listinfo/python-list
Re: Why does Python show the whole array?
Remeber the return value of find function of a string is -1 when it fails, which is True. Try: for item in isp: if item in test: print item From: Gilles Ganault nos...@nospam.com Date: April 8, 2009 5:56:34 PM CST To: python-list@python.org Subject: Why does Python show the whole array? Hello I'd like to go through a list of e-mail addresses, and extract those that belong to well-known ISP's. For some reason I can't figure out, Python shows the whole list instead of just e-mails that match: === script test = t...@gmail.com isp = [gmail.com, yahoo.com] for item in isp: if test.find(item): print item === output gmail.com yahoo.com === Any idea why I'm also getting yahoo.com? Thank you. -- http://mail.python.org/mailman/listinfo/python-list -- http://mail.python.org/mailman/listinfo/python-list
Re: Q: Best book for teaching
In message 8e3d0032-5e9f-44c2-9380-1d2383552...@u5g2000vbc.googlegroups.com, grkunt...@gmail.com wrote: I am considering teaching an introduction to programming course for continuing education adults at a local community college. These would people with no programming experience, but I will require a reasonable facility with computers. I thought that a good introduction might be to show them how HTML works, and progress from there to embedding little bits of JavaScript. Nothing to do with Python I know, but might be a possibility. -- http://mail.python.org/mailman/listinfo/python-list
Re: Why does Python show the whole array?
Gilles Ganault wrote: I'd like to go through a list of e-mail addresses, and extract those that belong to well-known ISP's. For some reason I can't figure out, Python shows the whole list instead of just e-mails that match: === script test = t...@gmail.com isp = [gmail.com, yahoo.com] for item in isp: if test.find(item): print item === output gmail.com yahoo.com === Any idea why I'm also getting yahoo.com? Because str.find() returns the position of the search string if found and -1 if it is not found: abc.find(bc) 1 abc.find(ab) 0 abc.find(x) -1 Use if test.find(item) != -1: ... or if item in test: ... to make your example work. Peter -- http://mail.python.org/mailman/listinfo/python-list
Re: TypeError: object cannot be interpreted as an index
tleeuwenb...@gmail.com tleeuwenb...@gmail.com (tc) wrote: tc What, exactly, needs to be in place for an object to be a valid tc dictionary key? It must have __hash__ and __cmp__ or __eq__ methods. Newstyle classes inherit these from object. -- Piet van Oostrum p...@cs.uu.nl URL: http://pietvanoostrum.com [PGP 8DAE142BE17999C4] Private email: p...@vanoostrum.org -- http://mail.python.org/mailman/listinfo/python-list
Re: List of paths
Here's a tricky case that doesn't show up in your example: In each case above, the directory names are distinct. how about: ['/desk', '/desk/ethanallen', '/desk/ikea', '/desktop', /desktop/pc', '/desktop/mac'] Should the answer be ['/desk'] or ['/desk', '/desktop'] ? Hi Scott good point. It should be: ['/desk', '/desktop'] -- http://mail.python.org/mailman/listinfo/python-list
Re: Why does Python show the whole array?
On Wed, 08 Apr 2009 12:11:55 +0200, Ulrich Eckhardt eckha...@satorlaser.com wrote: find() returns the index where it is found or -1 if it is not found. Both an index0 or a -1 evaluate to True when used as conditional expression. Thanks everyone. I shouldn't have assumed that if test.find(item): was necessarily enough to mean True. for item in isp: #GOOD if item in test: if test.find(item) 0: print test -- http://mail.python.org/mailman/listinfo/python-list
Python-URL! - weekly Python news and links (Apr 8)
QOTW: Those who show promise can advance to our Winter Improve Python to Expert program, for an additional fee, and, be given expert tutoring to help you gain our exemplary A.R.S.E./W.I.P.E certification which is guaranteed to attract certain types of employers by its name alone. - Paddy3118 http://groups.google.com/group/comp.lang.python/msg/f86e314251d94d96 Two new releases this week: * Python 3.1 alpha 2: http://mail.python.org/pipermail/python-list/2009-April/707817.html * and Python 2.6.2 candidate 1: http://mail.python.org/pipermail/python-list/2009-April/708214.html Dynamically adding new methods to a class hierarchy: http://groups.google.com/group/comp.lang.python/t/a6805cc39de3746a/ How to handle infinite generators (in the example, generating *all* prime numbers): http://groups.google.com/group/comp.lang.python/t/77cc9764f9d5a072/ Refactoring a giant class into smaller parts: http://groups.google.com/group/comp.lang.python/t/581d6b8dac0360d6/ People coming from static languages fear that Python code requires stronger unit tests - is that true? http://groups.google.com/group/comp.lang.python/t/8a3be7bb5ee1d1b4/ Synchronizing concurrent access to a dictionary: http://groups.google.com/group/comp.lang.python/t/d2156aa4aaf95bd5/ Can an object know whose attribute it is called upon? http://groups.google.com/group/comp.lang.python/t/1b43c60954e0a7a3/ Usually, returning different types based on input parameters is a bad idea: http://groups.google.com/group/comp.lang.python/t/b9fbef4368cf9981/ Everything Python-related you want is probably one or two clicks away in these pages: Python.org's Python Language Website is the traditional center of Pythonia http://www.python.org Notice especially the master FAQ http://www.python.org/doc/FAQ.html PythonWare complements the digest you're reading with the marvelous daily python url http://www.pythonware.com/daily Just beginning with Python? This page is a great place to start: http://wiki.python.org/moin/BeginnersGuide/Programmers The Python Papers aims to publish the efforts of Python enthusiats: http://pythonpapers.org/ The Python Magazine is a technical monthly devoted to Python: http://pythonmagazine.com Readers have recommended the Planet sites: http://planetpython.org http://planet.python.org comp.lang.python.announce announces new Python software. Be sure to scan this newsgroup weekly. http://groups.google.com/group/comp.lang.python.announce/topics Python411 indexes podcasts ... to help people learn Python ... Updates appear more-than-weekly: http://www.awaretek.com/python/index.html The Python Package Index catalogues packages. http://www.python.org/pypi/ The somewhat older Vaults of Parnassus ambitiously collects references to all sorts of Python resources. http://www.vex.net/~x/parnassus/ Much of Python's real work takes place on Special-Interest Group mailing lists http://www.python.org/sigs/ Python Success Stories--from air-traffic control to on-line match-making--can inspire you or decision-makers to whom you're subject with a vision of what the language makes practical. http://www.pythonology.com/success The Python Software Foundation (PSF) has replaced the Python Consortium as an independent nexus of activity. It has official responsibility for Python's development and maintenance. http://www.python.org/psf/ Among the ways you can support PSF is with a donation. http://www.python.org/psf/donations/ The Summary of Python Tracker Issues is an automatically generated report summarizing new bugs, closed ones, and patch submissions. http://search.gmane.org/?author=status%40bugs.python.orggroup=gmane.comp.python.develsort=date Although unmaintained since 2002, the Cetus collection of Python hyperlinks retains a few gems. http://www.cetus-links.org/oo_python.html Python FAQTS http://python.faqts.com/ The Cookbook is a collaborative effort to capture useful and interesting recipes. http://code.activestate.com/recipes/langs/python/ Many Python conferences around the world are in preparation. Watch this space for links to them. Among several Python-oriented RSS/RDF feeds available, see: http://www.python.org/channews.rdf For more, see: http://www.syndic8.com/feedlist.php?ShowMatch=pythonShowStatus=all The old Python To-Do List now lives principally in a SourceForge reincarnation. http://sourceforge.net/tracker/?atid=355470group_id=5470func=browse
Re: Why does Python show the whole array?
Gilles Ganault wrote: On Wed, 08 Apr 2009 12:11:55 +0200, Ulrich Eckhardt eckha...@satorlaser.com wrote: find() returns the index where it is found or -1 if it is not found. Both an index0 or a -1 evaluate to True when used as conditional expression. Thanks everyone. I shouldn't have assumed that if test.find(item): was necessarily enough to mean True. for item in isp: #GOOD if item in test: if test.find(item) 0: the post you quote has an error. you probably want -1 there. 0 is returned if the two strings match at the start. the problem is that the method return isn't consistent with implicit conversion to boolean; python does convert non-zero to True. andrew print test -- http://mail.python.org/mailman/listinfo/python-list -- http://mail.python.org/mailman/listinfo/python-list
Re: named pipe and Linux
On Apr 7, 1:08 pm, akineko akin...@gmail.com wrote: Hello everyone, I'm trying to use named pipes to fuse a Python program and a C program. One side creates pipes using os.mkfifo() and both sides use the same named pipes (one side reads, another side writes). The read side uses select.select() to wait for incoming messages and read the message when select.select() says it is ready. The length of the message is unknown to the read side. I cannot use file.read() because it will block waiting for an EOF. I cannot use file.readline() because how many lines have arrived is unknown. So, I needed to use os.read() with the exact number of characters to read. Under Solaris environment, os.fstat() provides the exact size of the message that has arrived. Thus, two processes can communicate each other through the named pipes without blocking. However, the above scheme didn't work under Linux. Linux os.fstat() returns size=0 even the message is pending. (I think Linux buffers the message in memory while Solaris buffers the message in a file system) My question is, how can I make the named pipe scheme work under Linux? Is there any way to read the message without getting blocked? I know this is more Linux question than Python question but I believe many Python programmers are strong Linux programmers. Any suggestions will be appreciated. Best regards, Aki Niimura The SIMPL open source project (http://www.icanprogram.com/simpl) provides an ultra lightweight toolkit useful for joining Python programs to C programs using a Send/Receive/Reply mechanism first pioneered by QNX.SIMPL uses a fifo synchronized shared memory scheme for the local message pass.Through the use of generic surrogate pairs SIMPL processes can be distributed across TCP/IP or RS232 (think radio modem) networks often times without any changes or recompiles. Through the use of another type of generic surrogate a Python module running on a nonLinux OS can communicate transparently with a module running on a Linux box. A SIMPL application consists of two or more SIMPL modules collaborating in this way. SIMPL modules can be written in any number of languages including Python, C, C++, Tcl/Tk or JAVA. More importantly SIMPL modules written in different languages can be mixed in a given SIMPL application. There is a Sudoku puzzle solver example here: http://www.icanprogram.com/simplBook/simplBook.self.html bob SIMPL project facilitator -- http://mail.python.org/mailman/listinfo/python-list
Re: Some test fail on my new Python 2.6
Sorin Schwimmer sx...@yahoo.com wrote: I wanted to replace my old Python 2.4 and tcl/tk 8.4 with tcl/tk 8.5.6 and Python 2.6, mainly so that I can enjoy ttk. tcl/tk was installed from sources without any problem, I started a wish and worked. Now, for the Python, here are all the issues signaled by make test: running build running build_ext building 'dbm' extension gcc -pthread -fPIC -fno-strict-aliasing -DNDEBUG -g -O3 -Wall -Wstrict-prototypes -DHAVE_GDBM_NDBM_H -I. -I/install/Python-2.6.1/./Include -I. -IInclude -I./Include -I/usr/local/include -I/install/Python-2.6.1/Include -I/install/Python-2.6.1 -c /install/Python-2.6.1/Modules/dbmmodule.c -o build/temp.linux-i686-2.6/install/Python-2.6.1/Modules/dbmmodule.o gcc -pthread -shared build/temp.linux-i686-2.6/install/Python-2.6.1/Modules/dbmmodule.o -L/usr/local/lib -lgdbm -o build/lib.linux-i686-2.6/dbm.so *** WARNING: renaming dbm since importing it failed: build/lib.linux-i686-2.6/dbm.so: undefined symbol: dbm_firstkey Ok, so DBM wasn't built because it couldn't find the external symbol 'dbm_firstkey'. I have no idea off the top of my head why that would happen, but I don't think you really care at the moment since you are trying to get tkinter working. If you do care we can come back to that. building '_tkinter' extension gcc -pthread -fPIC -fno-strict-aliasing -DNDEBUG -g -O3 -Wall -Wstrict-prototypes -DWITH_APPINIT=1 -DWITH_BLT=1 -I/usr/X11R6/include -I. -I/install/Python-2.6.1/./Include -I. -IInclude -I./Include -I/usr/local/include -I/install/Python-2.6.1/Include -I/install/Python-2.6.1 -c /install/Python-2.6.1/Modules/_tkinter.c -o build/temp.linux-i686-2.6/install/Python-2.6.1/Modules/_tkinter.o gcc -pthread -fPIC -fno-strict-aliasing -DNDEBUG -g -O3 -Wall -Wstrict-prototypes -DWITH_APPINIT=1 -DWITH_BLT=1 -I/usr/X11R6/include -I. -I/install/Python-2.6.1/./Include -I. -IInclude -I./Include -I/usr/local/include -I/install/Python-2.6.1/Include -I/install/Python-2.6.1 -c /install/Python-2.6.1/Modules/tkappinit.c -o build/temp.linux-i686-2.6/install/Python-2.6.1/Modules/tkappinit.o gcc -pthread -shared build/temp.linux-i686-2.6/install/Python-2.6.1/Modules/_tkinter.o build/temp.linux-i686-2.6/install/Python-2.6.1/Modules/tkappinit.o -L/usr/X11R6/lib64 -L/usr/X11R6/lib -L/usr/local/lib -lBLT -ltk8.5 -ltcl8.5 -lX11 -o build/lib.linux-i686-2.6/_tkinter.so *** WARNING: renaming _tkinter since importing it failed: libtk8.5.so: cannot open shared object file: No such file or directory Now, this one is clear. It couldn't find libtk8.5.so when it tried to use _tkinter.so. So either that symlink doesn't exist, or points to a nonexistent library, or there's something wrong with your load library path, so that python isn't finding it when it tries to do the load. If you don't know what that last one means, check out 'man ldconfig'. Failed to find the necessary bits to build these modules: _sqlite3 bsddb185 sunaudiodev Here you presumably don't have these libraries installed, so no real problem. To find the necessary bits, look in setup.py in detect_modules() for the module's name. Failed to build these modules: _tkinter dbm These we covered above. Most of the stuff you show from the test run is expected output for one reason or another. The ones that aren't... test_multiprocessing test_multiprocessing skipped -- OSError raises on RLock creation, see issue 3111! According to the referenced bug, this may be a result of your not having /dev/shm mounted, but in any case it is more a bug in the tests than a bug in your system or setup. test_socket test test_socket failed -- Traceback (most recent call last): File /install/Python-2.6.1/Lib/test/test_socket.py, line 474, in testSockName my_ip_addr = socket.gethostbyname(socket.gethostname()) gaierror: [Errno -2] Name or service not known This probably means that you haven't properly defined 'localhost' in your /etc/hosts file. test_sys test test_sys failed -- Traceback (most recent call last): File /install/Python-2.6.1/Lib/test/test_sys.py, line 354, in test_43581 self.assert_(sys.__stdout__.encoding == sys.__stderr__.encoding) AssertionError This one is puzzling. Did you modify 'site.py'? Or perhaps you redirected stdout and stderr to different places and they wound up with different encodings for some reason. In which case that one would be a bug in the tests as well. test_tcl test_tcl skipped -- No module named _tkinter This is a result of the build failure. 320 tests OK. 3 tests failed: test_httpservers test_socket test_sys So we understand test_socket and maybe test_sys. You'll have to show me the output of test_httpsservers run in verbose mode again to see if I can make sense of that one, if you care. 38 tests skipped: test_aepack test_al test_applesingle test_bsddb185 test_bsddb3 test_cd test_cl test_codecmaps_cn
genetic algorithms in Python?
Hello, Anyone using Python for coding up genetic algorithms? If so, would you share your favorite modules/libraries/tools? Thanks, Esmail -- http://mail.python.org/mailman/listinfo/python-list
Re: Adding method to class at run-time: bad style?
On 2009-04-08, Gabriel Genellina gagsl-...@yahoo.com.ar wrote: ClientForm.Control = FancyControl ClientForm.CheckboxControl = FancyCheckboxControl That would work -- but there are probably 8 or 10 different Control subclasses. It's a bit tedious mixing them all one at a time, and you need more inside information (the names of all the different subclasses). New style classes have a __subclasses__() method that could be used to find all of them (*at a certain moment*) -- but considering all the issues, I think that monkey-patching the base class is the less bad option in this case... Of course I could just -- Grant Edwards grante Yow! Th' MIND is the Pizza at Palace of th' SOUL visi.com -- http://mail.python.org/mailman/listinfo/python-list
Re: Adding method to class at run-time: bad style?
On 2009-04-08, Gabriel Genellina gagsl-...@yahoo.com.ar wrote: class Mixin: # or class Mixin(object) if new-style: def __eq__(self, other): return (self.type == other.type ... def __ne__(self, other): return not self.__eq__(other) class FancyControl(MixIn, ClientForm.Control): pass class FancyCheckboxControl(MixIn, ClientForm.CheckboxControl): pass .. ClientForm.Control = FancyControl ClientForm.CheckboxControl = FancyCheckboxControl That would work -- but there are probably 8 or 10 different Control subclasses. It's a bit tedious mixing them all one at a time, and you need more inside information (the names of all the different subclasses). New style classes have a __subclasses__() method that could be used to find all of them (*at a certain moment*) -- but considering all the issues, I think that monkey-patching the base class is the less bad option in this case... I agree. Inserting methods into the base class seems to be working fine, and it's the least messy of the alternatives. I'd submit a patch for ClientForm, but I don't know if my definition of equal for a form/control is generally useful enough to warrant being added to the package. FWIW, I'm using it for automated regression-testing on a product containing a web server. Basically, I perform an operation on the product, and then check to make sure that only certain web pages/form/controls changed in the manner they should have. -- Grant Edwards grante Yow! ... the HIGHWAY is at made out of LIME JELLO and visi.commy HONDA is a barbequeued OYSTER! Yum! -- http://mail.python.org/mailman/listinfo/python-list
Re: Returning different types based on input parameters
On Apr 7, 3:18 pm, Adam Olsen rha...@gmail.com wrote: On Apr 6, 3:02 pm, George Sakkis george.sak...@gmail.com wrote: For example, it is common for a function f(x) to expect x to be simply iterable, without caring of its exact type. Is it ok though for f to return a list for some types/values of x, a tuple for others and a generator for everything else (assuming it's documented), or it should always return the most general (iterator in this example) ? For list/tuple/iterable the correlation with the argument's type is purely superficial, *because* they're so compatible. Why should only tuples and lists get special behaviour? Why shouldn't every other argument type return a list as well? That's easy; because the result might be infinite. In which case you may ask why shouldn't every argument type return an iterator then, and the reason is usually performance; if you already need to store the whole result sequence (e.g. sorted()), why return just an iterator to it and force the client to copy it to another list if he needs anything more than iterating once over it ? A counter example is python 3.0's str/bytes functions. They're mutually incompatible and there's no default. As already mentioned, another example is filter() that tries to match the input sequence type and falls back to list if it fails. To take it further, what if f wants to return different types, differing even in a duck-type sense? That's easier to illustrate in a API-extension scenario. Say that there is an existing function `solve (x)` that returns `Result` instances. Later someone wants to extend f by allowing an extra optional parameter `foo`, making the signature `solve(x, foo=None)`. As long as the return value remains backward compatible, everything's fine. However, what if in the extended case, solve() has to return some *additional* information apart from `Result`, say the confidence that the result is correct ? In short, the extended API would be: def solve(x, foo=None): ''' @rtype: `Result` if foo is None; (`Result`, confidence) otherwise. ''' Strictly speaking, the extension is backwards compatible; previous code that used `solve(x)` will still get back `Result`s. The problem is that in new code you can't tell what `solve(x,y)` returns unless you know something about `y`. My question is, is this totally unacceptable and should better be replaced by a new function `solve2 (x, foo=None)` that always returns (`Result`, confidence) tuples, or it might be a justifiable cost ? Any other API extension approaches that are applicable to such situations ? At a minimum it's highly undesirable. You lose a lot of readability/ maintainability. solve2/solve_ex is a little ugly, but that's less overall, so it's the better option. That's my feeling too, at least in a dynamic language. For a static language that allows overloading, that should be a smaller (or perhaps no) issue. George -- http://mail.python.org/mailman/listinfo/python-list
Re: SoHo Book Problem
Never mind (at least tentatively). Later in the day I got an email from the publisher, saying they're going to send me a corrected copy free. Evidently if you get a bad copy you don't have to complain to the publisher or the retailer, you just have to post a complaint somewhere where Google can see it... DU. In article dullrich-5ea218.10405607042...@text.giganews.com, David C. Ullrich dullr...@sprynet.com wrote: Just curious - has anyone else bought the printed Python 3 Reference Manual published by SoHo Books? Talking about what they call Part 2 of their Python Documentation. I haven't looked in detail - Part 1 seems fine, but the typesetting in Part 2 is totally screwed up. I mean totally - on more or less every page there are lines that are unreadable because there are words printed on top of each other instead of next to each other! On the one hand I don't see how the problem could be with just my copy. On the other hand I don't see how they could _all_ be like mine - that would mean nobody even _glanced_ at what was coming out of the press. So I'm curious whether anyone else has a copy. (I know it's all online. Some people like _books_...) DU. -- David C. Ullrich -- http://mail.python.org/mailman/listinfo/python-list
Re: more fun with iterators (mux, demux)
pataphor wrote: On 07 Apr 2009 02:05:59 GMT Steven D'Aprano ste...@remove.this.cybersource.com.au wrote: The demuxer can't be an iterator, since it needs to run through the entire collection. Then your demuxer obviously cannot handle infinite sequences. def demux(it, n): collectors = [[] for i in xrange(n)] i = 0 for item in it: collectors[i].append(item) i = (i+1) % n return tuple([iter(x) for x in collectors]) But this one can: from collections import deque from itertools import cycle, izip, count, islice def mux(*iterables): for it in izip(*iterables): for item in it: yield item def demux(seq,n): it = iter(seq) Q = [deque() for i in xrange(n)] CQ = cycle(Q) def gen(D): for x,C in izip(it,CQ): C.appendleft(x) while D: yield D.pop() while D: yield D.pop() return map(gen,Q) def test(): a = count(10) b = count(20) c = count (30) x = demux(mux(a,b,c),3) for e in x: print list(islice(e,0,10)) if __name__=='__main__': test() P. -- http://mail.python.org/mailman/listinfo/python-list What was wrong with this one? def demux(iterable, n): return tuple(islice(it, i, None, n) for (i, it) in enumerate(tee(iterable, n))) -- http://mail.python.org/mailman/listinfo/python-list
Simple CGI request and Python reply
Hello,
I'm trying to implement something very simple without using a Python
WebFramework and I need some advice. I want to send a comma delimited string
from the client to a server-side Python script. My initial plan was to use a
JavaScript function (see below) called makerequest that creates a
XMLHttpRequest object and GETs the output from a Python script. I've used
this function before to field requests (in those cases the parameter data
passed in the XMLHttpRequest.send() method is null). So I thought I could
just pass some data in and be able to retrieve it with Python. I'm not sure
how to do this. I've used forms with cgi/Python before. However, I don't
want to use a form here. I want Python to handle the data variable being
passed without looking for field names using .FieldStorage(). Can that be
done?
Maybe making a request is not the quickest route to do what I want. Ideas?
function makerequest(serverPage,objID,data)
{
var obj = document.getElementById(objID);
xmlhttp.open(GET,serverPage);
xmlhttp.onreadystatechange = function()
{
if(xmlhttp.readyState == 4 xmlhttp.status == 200)
{
obj.innerHTML = xmlhttp.responseText;
}
}
xmlhttp.send(data);
}
--
View this message in context:
http://www.nabble.com/Simple-CGI-request-and-Python-reply-tp22952274p22952274.html
Sent from the Python - python-list mailing list archive at Nabble.com.
--
http://mail.python.org/mailman/listinfo/python-list
Re: CGIXMLRPCRequestHandler example
On Apr 5, 12:24 pm, a...@pythoncraft.com (Aahz) wrote: [posted e-mailed, please respond on-group] There was some problem with the CGIXMLRPCRequestHandler code in the SimpleXMLRPC Server. It was not getting the length to read from the CONTENT_LENGTH environement variable ( as it the CGI server was doing). It was fixed during PyCon sprints: http://svn.python.org/view?view=revrevision=70940 -- http://mail.python.org/mailman/listinfo/python-list
Re: genetic algorithms in Python?
I have done something in this direction. I will be happy to share my experience. However, my code is not generic and needs many things to be manually introduced. My GA is standard (selection by roulette wheel or tournament, single point cross). Let me know if you are interested! On Wed, Apr 8, 2009 at 3:25 PM, Esmail ebo...@hotmail.com wrote: Hello, Anyone using Python for coding up genetic algorithms? If so, would you share your favorite modules/libraries/tools? Thanks, Esmail -- http://mail.python.org/mailman/listinfo/python-list -- http://mail.python.org/mailman/listinfo/python-list
Re: Some test fail on my new Python 2.6
Thanks for the pointers. Here are some answers: Ok, so DBM wasn't built because it couldn't find the external symbol 'dbm_firstkey'. I have no idea off the top of my head why that would happen, but I don't think you really care at the moment since you are trying to get tkinter working. If you do care we can come back to that. Although I can live without it, I do use sometime dbm. And then, again, there are other ways to accomplish the same, so it's not critical. building '_tkinter' extension gcc -pthread -fPIC -fno-strict-aliasing -DNDEBUG -g -O3 -Wall -Wstrict-prototypes -DWITH_APPINIT=1 -DWITH_BLT=1 -I/usr/X11R6/include -I. -I/install/Python-2.6.1/./Include -I. -IInclude -I./Include -I/usr/local/include -I/install/Python-2.6.1/Include -I/install/Python-2.6.1 -c /install/Python-2.6.1/Modules/_tkinter.c -o build/temp.linux-i686-2.6/install/Python-2.6.1/Modules/_tkinter.o gcc -pthread -fPIC -fno-strict-aliasing -DNDEBUG -g -O3 -Wall -Wstrict-prototypes -DWITH_APPINIT=1 -DWITH_BLT=1 -I/usr/X11R6/include -I. -I/install/Python-2.6.1/./Include -I. -IInclude -I./Include -I/usr/local/include -I/install/Python-2.6.1/Include -I/install/Python-2.6.1 -c /install/Python-2.6.1/Modules/tkappinit.c -o build/temp.linux-i686-2.6/install/Python-2.6.1/Modules/tkappinit.o gcc -pthread -shared build/temp.linux-i686-2.6/install/Python-2.6.1/Modules/_tkinter.o build/temp.linux-i686-2.6/install/Python-2.6.1/Modules/tkappinit.o -L/usr/X11R6/lib64 -L/usr/X11R6/lib -L/usr/local/lib -lBLT -ltk8.5 -ltcl8.5 -lX11 -o build/lib.linux-i686-2.6/_tkinter.so *** WARNING: renaming _tkinter since importing it failed: libtk8.5.so: cannot open shared object file: No such file or directory Now, this one is clear. It couldn't find libtk8.5.so when it tried to use _tkinter.so. So either that symlink doesn't exist, or points to a nonexistent library, or there's something wrong with your load library path, so that python isn't finding it when it tries to do the load. If you don't know what that last one means, check out 'man ldconfig'. # pwd /usr/local/lib # ls libpq.so.4libtcl8.4.so libtclstub8.4.a libtk8.4.so libtkstub8.4.a python2.4 tcl8.4 tclConfig.sh tk8.5 libpq.so.4.0 libtcl8.5.so libtclstub8.5.a libtk8.5.so libtkstub8.5.a tcl8 tcl8.5 tk8.4 tkConfig.sh It's there! test_multiprocessing test_multiprocessing skipped -- OSError raises on RLock creation, see issue 3111! According to the referenced bug, this may be a result of your not having /dev/shm mounted, but in any case it is more a bug in the tests than a bug in your system or setup. # mount /dev/hda3 on / type reiserfs (rw,noatime) proc on /proc type proc (rw) sysfs on /sys type sysfs (rw) udev on /dev type tmpfs (rw,nosuid) devpts on /dev/pts type devpts (rw) shm on /dev/shm type tmpfs (rw,noexec,nosuid,nodev) usbfs on /proc/bus/usb type usbfs (rw,devmode=0664,devgid=85) It's there, but if it is about a known bug in the test, maybe we should just ignore it? test_socket test test_socket failed -- Traceback (most recent call last): File /install/Python-2.6.1/Lib/test/test_socket.py, line 474, in testSockName my_ip_addr = socket.gethostbyname(socket.gethostname()) gaierror: [Errno -2] Name or service not known This probably means that you haven't properly defined 'localhost' in your /etc/hosts file. # cat /etc/hosts # /etc/hosts # # This file describes a number of hostname-to-address # mappings for the TCP/IP subsystem. It is mostly # used at boot time, when no name servers are running. # On small systems, this file can be used instead of a # named name server. Just add the names, addresses # and any aliases to this file... # 127.0.0.1 localhost # IPV6 versions of localhost and co ::1 ip6-localhost ip6-loopback fe00::0 ip6-localnet ff00::0 ip6-mcastprefix ff02::1 ip6-allnodes ff02::2 ip6-allrouters ff02::3 ip6-allhosts There is a localhost definition. Is it not correct? test_sys test test_sys failed -- Traceback (most recent call last): File /install/Python-2.6.1/Lib/test/test_sys.py, line 354, in test_43581 self.assert_(sys.__stdout__.encoding == sys.__stderr__.encoding) AssertionError This one is puzzling. Did you modify 'site.py'? Or perhaps you redirected stdout and stderr to different places and they wound up with different encodings for some reason. In which case that one would be a bug in the tests as well. No, I didn't, nor have I done anything with stdout, stderror. When I ran the test, I did a make test | tee test.rez, which in my mind should have been harmless. The output for individual test_httpservers was posted here: http://mail.python.org/pipermail/python-list/2009-April/708041.html Thanks again SxN __ Yahoo! Canada Toolbar: Search from anywhere on the web, and bookmark your favourite sites. Download it now http://ca.toolbar.yahoo.com. --
Re: Scraping a web page
On Apr 7, 1:44 pm, Tim Chase python.l...@tim.thechases.com wrote: f = urllib.urlopen(http://www.google.com;) s = f.read() It is working, but it's returning the source of the page. Is there anyway I can get almost a screen capture of the page? This is the job of a browser -- to render the source HTML. As such, you'd want to look into any of the browser-automation libraries to hook into IE, FireFox, Opera, or maybe using the WebKit/KHTML control. You may then be able to direct it to render the HTML into a canvas you can then treat as an image. Another alternative might be provided by some web-services that will render a page as HTML with various browsers and then send you the result. However, these are usually either (1) asynchronous or (2) paid services (or both). -tkc WX can render html. -- http://mail.python.org/mailman/listinfo/python-list
Python 3.0 online docs broken
Jim Garrison wrote: Ye Liu wrote: On Apr 6, 6:33 pm, Jim Garrison j...@acm.org wrote: I notice the online docs (at docs.python.org/3.0/index.html) were updated today. It seems some of the top-level pages, like Tutorial, Using Python, Language Reference are truncated after the first few paragraphs. Yea, same here. Hope it's going to be fixed soon. Still broken. I've emailed webmaster(at)python.org I'm still seeing only stubs for many of the doc pages at docs.python.org. For example http://docs.python.org/3.0/tutorial/index.html This page stops at the sentence The Glossary is also worth going through. whereas it used to be followed by a hyperlinked table of contents for all the tutorial pages. I emailed the webmaster but have received no response. Am I the only one seeing this? -- http://mail.python.org/mailman/listinfo/python-list
Re: genetic algorithms in Python??
Hello Mohammed, Yes, that would great. While I am comfortable with GAs, I'm still rather inexperienced with Python so seeing some implementation examples would be very useful. Thanks, Esmail -- Date: Wed, 8 Apr 2009 17:08:48 +0200 Subject: Re: genetic algorithms in Python? From: medmedi...@gmail.com To: ebo...@hotmail.com CC: python-list@python.org I have done something in this direction. I will be happy to share my experience. However, my code is not generic and needs many things to be manually introduced. My GA is standard (selection by roulette wheel or tournament, single point cross). Let me know if you are interested! On Wed, Apr 8, 2009 at 3:25 PM, Esmail ebo...@hotmail.com wrote: Hello, Anyone using Python for coding up genetic algorithms? If so, would you share your favorite modules/libraries/tools? Thanks, Esmail -- http://mail.python.org/mailman/listinfo/python-list
how to get back an object from its id() value
Hi everybody,
I have a data structure (a tree) that has one constraint: I can only store
strings in this data structure.
To know if an object foo already exists in memory, I store str(id(foo)) in
the data structure.
OK.
But how do I get a usable reference from the id value?
For example, if foo has a method bar(), how can I call foo.bar()
from str(id(foo)) (say, 149466208).
Thanks in advance,
Julien
--
python -c print ''.join([chr(154 - ord(c)) for c in '*9(9(18%.\
91+,\'Z4(55l4('])
When a distinguished but elderly scientist states that something is
possible, he is almost certainly right. When he states that something is
impossible, he is very probably wrong. (first law of AC Clarke)
--
http://mail.python.org/mailman/listinfo/python-list
How to ignore white space changes using difflib?
I'm trying to use difflib to compare strings ignoring changes to white-space (space/tab). According to the doc page, you can do this by specifying a charjunk parameter to filter out characters: charjunk: A function that accepts a character (a string of length 1), and returns if the character is junk, or false if not. The default is module-level function IS_CHARACTER_JUNK(), which filters out whitespace characters (a blank or tab; note: bad idea to include newline in this!). But, I simply can't get it to work. I get exactly the same results with or without white-space filtering: Here's my test program: #!/usr/bin/python import difflib d1 = [this is string one,this is string two,this is string three] d2 = [this is string one,this is string two,this is string three] def iswhite(c): return c in \t print no filtering delta = difflib.ndiff(d1,d2) for line in delta: print line print print print IS_CHARACTER_JUNK delta = difflib.ndiff(d1,d2,charjunk=difflib.IS_CHARACTER_JUNK) for line in delta: print line print print print iswhite delta = difflib.ndiff(d1,d2,charjunk=iswhite) for line in delta: print line print And here's the output: no filtering this is string one - this is string two ?-- + this is string two ? + + this is string three IS_CHARACTER_JUNK this is string one - this is string two ?-- + this is string two ? + + this is string three iswhite this is string one - this is string two ?-- + this is string two ? + + this is string three What am I doing wrong? -- Grant Edwards grante Yow! I'll show you MY at telex number if you show me visi.comYOURS ... -- http://mail.python.org/mailman/listinfo/python-list
Floor value in math operators
Hi, This will be a very simple question to ask all the awesome programmers here: How can I get answer in in decimals for such a math operator: 3/2 I get 1. I want to get 1.5 Thanks in advance, Avi -- http://mail.python.org/mailman/listinfo/python-list
Re: Floor value in math operators
On Wed, Apr 8, 2009 at 9:03 AM, Avi avinashr...@gmail.com wrote: Hi, This will be a very simple question to ask all the awesome programmers here: How can I get answer in in decimals for such a math operator: 3/2 I get 1. I want to get 1.5 Add the following line to the top of your program (or use Python 3.0+): from __future__ import division To get integer division when this is enabled, use the integer division operator, // e.g. x = 3//2 #x=1 Cheers, Chris -- I have a blog: http://blog.rebertia.com -- http://mail.python.org/mailman/listinfo/python-list
Re: how to get back an object from its id() value
But how do I get a usable reference from the id value? For example, if foo has a method bar(), how can I call foo.bar() from str(id(foo)) (say, 149466208). can you just use a weakref instead? It is certainly cleaner than trying to store id's, since an id is only guaranteed to be unique for the lifetime of the object in question, and the only way I know of correlating id's to objects involves some C- level trickery. for completeness- the trickery: http://www.friday.com/bbum/2007/08/24/python-di/ -- http://mail.python.org/mailman/listinfo/python-list
Re: how to get back an object from its id() value
TP wrote: Hi everybody, I have a data structure (a tree) that has one constraint: I can only store strings in this data structure. To know if an object foo already exists in memory, I store str(id(foo)) in the data structure. OK. But how do I get a usable reference from the id value? For example, if foo has a method bar(), how can I call foo.bar() from str(id(foo)) (say, 149466208). You could create a dict with the string as the key and the object as the value. -- http://mail.python.org/mailman/listinfo/python-list
Re: how to get back an object from its id() value
TP wrote: Hi everybody, I have a data structure (a tree) that has one constraint: I can only store strings in this data structure. To know if an object foo already exists in memory, I store str(id(foo)) in the data structure. OK. But how do I get a usable reference from the id value? For example, if foo has a method bar(), how can I call foo.bar() from str(id(foo)) (say, 149466208). Short answer: You can't! Longer answer: You still can't, but you may be able to work around it: (1) Build up a dictionary in parallel to the structure: idMapper[id(foo)] = foo and later, index with idMapper[int(idString)] to get foo back (2) Get a different data structure. This one is clearly not satisfying your needs. (3) Pickle (or marshal or serialize as it's also called) your object into a (perhaps) long string to store. When the string is retrieved, unpickle to reconstruct an equivalent object. This new version of the original foo may or may not be adequate for your use. Gary Herron Thanks in advance, Julien -- http://mail.python.org/mailman/listinfo/python-list
Re: How to ignore white space changes using difflib?
On 2009-04-08, Grant Edwards inva...@invalid wrote: I'm trying to use difflib to compare strings ignoring changes to white-space (space/tab). According to the doc page, you can do this by specifying a charjunk parameter to filter out characters: charjunk: A function that accepts a character (a string of length 1), and returns if the character is junk, or false if not. The default is module-level function IS_CHARACTER_JUNK(), which filters out whitespace characters (a blank or tab; note: bad idea to include newline in this!). Apparently that filtering out characters doesn't mean that they're ignored when doing the comparison. (A bit of a WTF? if you ask me). After some more googling, it appears that I'm far from the first person who interpreted filtered out as ignored when comparing lines. I'd submit a fix for the doc page, but you apparently have to be a lot smarter than me to figure out what filters out means in this context. I guess I can collapse all whitespace sequences, do the diff on the collapsed lines, and them map the results back to the original lines. :/ What am I doing wrong? Reading the doc page, apparently. ;) -- Grant Edwards grante Yow! Not SENSUOUS ... only at FROLICSOME ... and in visi.comneed of DENTAL WORK ... in PAIN!!! -- http://mail.python.org/mailman/listinfo/python-list
Re: Floor value in math operators
Avi wrote: Hi, This will be a very simple question to ask all the awesome programmers here: How can I get answer in in decimals for such a math operator: 3/2 I get 1. I want to get 1.5 You don't say which python-version you have. Depending on that, the answer is different. In python2.5 and before, dividing two integers will always return an integer. So for your problem, you need to do 3.0 / 2.0 At least one of the involved numbers must be a float. However, from python2.5 the division operator behavior changed if desired - if you do from __future__ import division 3 / 2 1.5 3 // 2 1 you get what you expect. The old division operator is still available, as // In python2.6 and 3.x, the new behavior is standard. Diez -- http://mail.python.org/mailman/listinfo/python-list
Re: how to get back an object from its id() value
snip You could create a dict with the string as the key and the object as the value. /snip This will create a strong reference to the object, which is (I'm assuming) undesired behavior. -- http://mail.python.org/mailman/listinfo/python-list
Re: genetic algorithms in Python??
Esmail esmail...@gmail.com wrote: Hello Mohammed, Yes, that would great. While I am comfortable with GAs, I'm still rather inexperienced with Python so seeing some implementation examples would be very useful. A google for 'python genetic algorithms' turns up a number of interesting hits. I also remember seeing at least one package announced on python-announce that referred to genetic algorithms, so you might check the archives of that mailing list as well. -- R. David Murray http://www.bitdance.com -- http://mail.python.org/mailman/listinfo/python-list
Re: Python 3.0 online docs broken
Jim Garrison j...@acm.org Jim Garrison wrote: Ye Liu wrote: On Apr 6, 6:33 pm, Jim Garrison j...@acm.org wrote: I notice the online docs (at docs.python.org/3.0/index.html) were updated today. It seems some of the top-level pages, like Tutorial, Using Python, Language Reference are truncated after the first few paragraphs. Yea, same here. Hope it's going to be fixed soon. Still broken. I've emailed webmaster(at)python.org I'm still seeing only stubs for many of the doc pages at docs.python.org. For example http://docs.python.org/3.0/tutorial/index.html This page stops at the sentence The Glossary is also worth going through. whereas it used to be followed by a hyperlinked table of contents for all the tutorial pages. When I looked now (6:30 pm in South Africa) the links were back. The last one is representation error and it was all right when I clicked on it. - Hendrik -- http://mail.python.org/mailman/listinfo/python-list
Re: how to get back an object from its id() value
MRAB wrote:
You could create a dict with the string as the key and the object as the
value.
Thanks. But it implies an additional data structure: a dictionnary.
I don't know what is the best:
* using an additional dict and maintaining it
* or using the di module proposed by CTO
If di is reliable, it seems a good solution for my initial constraint
which is the impossibility to store anything but strings in my data
structure.
--
python -c print ''.join([chr(154 - ord(c)) for c in '*9(9(18%.\
91+,\'Z4(55l4('])
When a distinguished but elderly scientist states that something is
possible, he is almost certainly right. When he states that something is
impossible, he is very probably wrong. (first law of AC Clarke)
--
http://mail.python.org/mailman/listinfo/python-list
Re: Floor value in math operators
In python2.6 and 3.x, the new behavior is standard. Apparently that is nonsense - it seems to be not standard for 2.6. Which Makes sense I guess. Diez -- http://mail.python.org/mailman/listinfo/python-list
Re: how to get back an object from its id() value
I don't know what is the best: * using an additional dict and maintaining it It works, but as you say, is somewhat inelegant. * or using the di module proposed by CTO Let me be clear: I am not proposing that you use it. It *does* do what you ask- but what you are asking is, all by itself, not a good idea. The dict is a vastly superior- and standard- solution to the problem of mapping one object onto another. If di is reliable, it seems a good solution for my initial constraint which is the impossibility to store anything but strings in my data structure. di is not reliable. Its author says so, and took a lot of heat for not saying so in Hollywood-sign letters, lit on fire and a thousand feet tall. If all you are worried about is storing a string, how about UserString? Notice the difference: from collections import UserString import weakref weakref.ref(ABC) Traceback (most recent call last): File stdin, line 1, in module TypeError: cannot create weak reference to 'str' object weakref.ref(UserString(ABC)) weakref at 0xb7baef2c; to 'UserString' at 0xb7a330ec This way you don't have to maintain a dictionary, only store your string once, and don't have to hack and kludge your way around id mappings. -- http://mail.python.org/mailman/listinfo/python-list
asynchronous python call
Complete newbie, so forgive my improper use of Python terminology. I am working with Django and I have to send off a number of emails after a person has filled out a form. What I want is to make a call that goes off to form and send the emails and redirect the user to another view. I have this working now, but I noticed it is a bit slow. So I was hoping there was a way to spin off the process and redirect the user to the page while the emails are being formed and sent vs. making the page hang while it is done. Thank you! -- http://mail.python.org/mailman/listinfo/python-list
Re: Python syntax
On Apr 7, 11:39 pm, Lawrence D'Oliveiro l...@geek- central.gen.new_zealand wrote: In message mailman.3514.1239161591.11746.python-l...@python.org, Steve Holden wrote: Lawrence D'Oliveiro wrote: In message 7dd228af- e549-444d-8623-11e951851...@y9g2000yqg.googlegroups.com, janus99 wrote: I messed around with my own comp (windos xp) command prompt ... Try a Linux command prompt. You'll learn a bit more that way. Great advice when Linux is available, but somewhat fatuous for a Windows user. How hard is it to install Cygwin It's actually quite difficult. Even if you think ahead and ask that the various compilers are to be installed, that won't include various utilities like make (which are part of a different install component). It takes a lot of trial and error trying to get, say, GMP to compile. or download a live CD? -- http://mail.python.org/mailman/listinfo/python-list
Re: how to get back an object from its id() value
Correction: the UserString will be dead on the final line. When I typed it in I had a strong reference still hanging around. -- http://mail.python.org/mailman/listinfo/python-list
Re: 3D plotting in a GUI
Stef Mientki wrote: Baris Demir wrote: Hi all, I need to develop a GUI for some scientific data processing operations and this GUI should work well with a 3D plotting module, also with NumPy and SciPy for sure. I made a search about packages but, there are plenty of these modules available. What kind of a package or a package of packages might be the best way for this work. BTW I do not want to use MayaVi. It is too much actually. What do you mean by too much actually ? What's the GUI you had in mind ? What kind of scientific data processing do you've in mind ? cheers, Stef I am quite experienced about python programming but this is going to be my first GUI design. I need to draw some 2D graphs (also capability for 3D graphs might be very delicious) and do some mathematical operations on them like adding, substracting, smoothing, integration, detecting peak points and marking them, fourier transformations and etc. on WindowsXP. And then I want to convert this python code into a .exe by using py2exe. I said Mayavi is too much for me because I thought that it would be more likeyl to have problems while using a big package like MayaVi with py2exe. Thanks in advance. BD -- http://mail.python.org/mailman/listinfo/python-list -- http://mail.python.org/mailman/listinfo/python-list -- http://mail.python.org/mailman/listinfo/python-list
Re: Floor value in math operators
Avi wrote: Hi, This will be a very simple question to ask all the awesome programmers here: How can I get answer in in decimals for such a math operator: 3/2 I get 1. I want to get 1.5 Thanks in advance, Avi I'm going to assume your operands are variables instead of numeric literals. Why not consider doing a type conversion to float or Decimal and then perform the division? --David -- http://mail.python.org/mailman/listinfo/python-list
Re: Some test fail on my new Python 2.6
Sorin Schwimmer sx...@yahoo.com wrote:
Thanks for the pointers.
Here are some answers:
Ok, so DBM wasn't built because it couldn't find the external symbol
'dbm_firstkey'. I have no idea off the top of my head why that would
happen, but I don't think you really care at the moment since you are
trying to get tkinter working. If you do care we can come back to that.
Although I can live without it, I do use sometime dbm. And then, again,
there are other ways to accomplish the same, so it's not critical.
OK, so we'll come back to it later.
*** WARNING: renaming _tkinter since importing it failed: libtk8.5.so:
cannot open shared object file: No such file or directory
Now, this one is clear. It couldn't find libtk8.5.so when it tried to
use _tkinter.so. So either that symlink doesn't exist, or points to a
nonexistent library, or there's something wrong with your load library
path, so that python isn't finding it when it tries to do the load.
If you don't know what that last one means, check out 'man ldconfig'.
# pwd
/usr/local/lib
# ls
libpq.so.4libtcl8.4.so libtclstub8.4.a libtk8.4.so libtkstub8.4.a
python2.4 tcl8.4 tclConfig.sh tk8.5
libpq.so.4.0 libtcl8.5.so libtclstub8.5.a libtk8.5.so libtkstub8.5.a
tcl8 tcl8.5 tk8.4 tkConfig.sh
It's there!
Well, there is _something_ there. Maybe it's a symbolic link that
doesn't point anywhere? Do ls -l, and/or 'file' on it just to check.
The above message is what you would get if it were a symbolic link
that didn't point anywhere valid.
Oh, and make sure /usr/local/lib is in your /etc/ld.so.conf file. If
it isn't, then that's your problem. If you need to update that
file I'm pretty sure you need to run ldconfig afterwards.
test_multiprocessing
test_multiprocessing skipped -- OSError raises on RLock creation, see
issue 3111!
According to the referenced bug, this may be a result of your not having
/dev/shm mounted, but in any case it is more a bug in the tests than a
bug in your system or setup.
# mount
/dev/hda3 on / type reiserfs (rw,noatime)
proc on /proc type proc (rw)
sysfs on /sys type sysfs (rw)
udev on /dev type tmpfs (rw,nosuid)
devpts on /dev/pts type devpts (rw)
shm on /dev/shm type tmpfs (rw,noexec,nosuid,nodev)
usbfs on /proc/bus/usb type usbfs (rw,devmode=0664,devgid=85)
It's there, but if it is about a known bug in the test, maybe we should just
ignore it?
Yeah. Or download 2.6.2c1 and see if that has the same problem. The bug
doesn't say that it was fixed in 2.6.2, and the conditional skip is
still there in the test, but I know Jesse was doing work in that area,
so it might get past it on 2.6.2.
On the other hand, if you aren't using multiprocessing you don't need
to worry about it.
test_socket
test test_socket failed -- Traceback (most recent call last):
File /install/Python-2.6.1/Lib/test/test_socket.py, line 474, in
testSockName
my_ip_addr = socket.gethostbyname(socket.gethostname())
gaierror: [Errno -2] Name or service not known
This probably means that you haven't properly defined 'localhost'
in your /etc/hosts file.
# cat /etc/hosts
# /etc/hosts
#
# This file describes a number of hostname-to-address
# mappings for the TCP/IP subsystem. It is mostly
# used at boot time, when no name servers are running.
# On small systems, this file can be used instead of a
# named name server. Just add the names, addresses
# and any aliases to this file...
#
127.0.0.1 localhost
# IPV6 versions of localhost and co
::1 ip6-localhost ip6-loopback
fe00::0 ip6-localnet
ff00::0 ip6-mcastprefix
ff02::1 ip6-allnodes
ff02::2 ip6-allrouters
ff02::3 ip6-allhosts
There is a localhost definition. Is it not correct?
Yes, but...I just did the functions on my own machine and got this:
Python 2.6.1 (r261:67515, Mar 26 2009, 08:03:17)
[GCC 4.1.2 (Gentoo 4.1.2)] on linux2
Type help, copyright, credits or license for more information.
import socket
socket.gethostname()
'partner'
socket.gethostbyname('partner')
'127.0.0.1'
So I suspect that you need to add your hostname to the 'localhost' line in
order to get that test to pass. Mine looks like this:
127.0.0.1 partner.bitdance.com partner localhost
I'm inclined to call that a bug in the tests. You could file a bug
report if you feel so moved :)
test_sys
test test_sys failed -- Traceback (most recent call last):
File /install/Python-2.6.1/Lib/test/test_sys.py, line 354, in
test_43581
self.assert_(sys.__stdout__.encoding == sys.__stderr__.encoding)
AssertionError
This one is puzzling. Did you modify 'site.py'? Or perhaps you
redirected stdout and stderr to different places and they
wound up with different encodings for some reason. In which
case that one would be a bug in the tests as well.
No, I didn't, nor have I done anything with stdout, stderror. When I ran the
Re: How to ignore white space changes using difflib?
Grant Edwards inva...@invalid wrote:
Apparently that filtering out characters doesn't mean that
they're ignored when doing the comparison. (A bit of a WTF?
if you ask me). After some more googling, it appears that I'm
far from the first person who interpreted filtered out as
ignored when comparing lines. I'd submit a fix for the doc
page, but you apparently have to be a lot smarter than me to
figure out what filters out means in this context.
So far as I can see from looking at the code:
Once if you have identified one block of lines as having been replaced by
another the matcher can then give you additional information by marking up
the changes within each line. However it only makes sense to do that if the
lines are still somewhat similar.
'charjunk' is used to remove junk characters before scanning the lines
within a replacement block and the most similar lines (if they are
sufficiently similar) are then chosen for this extra step of comparing the
character changes within the line.
Here's an example. If I do this:
print ''.join(Differ().compare('one\ntwo\nthree\n'.splitlines(1),
'one\nwot\ntoo\nthree\n'.splitlines(1)))
one
- two
? -
+ wot
? +
+ too
three
The comparison detected that two was replaced by 2 lines wot and too.
It decided the first of these was the best match for the original line so
it shows character level difference between the original and the first
replacement line.
print ''.join(Differ(charjunk=lambda c:c=='w')
.compare('one\ntwo\nthree\n'.splitlines(1),
'one\nwot\ntoo\nthree\n'.splitlines(1)))
one
+ wot
- two
? ^
+ too
? ^
three
This time we told the system that we don't care about 'w' in either the
original or replacement text. That means instead of seeing which of wot
and too is closest to two it looks to see which of ot and too is
closest to to. ot has two changes but too only has one, so this time
it does the detailed comparison between the original line and the second
line of the output. N.B. The junk function is only used to decide which
lines to use for the detailed comparison: the original lines are still used
for the comparison itself.
--
http://mail.python.org/mailman/listinfo/python-list
Re: more fun with iterators (mux, demux)
On Wed, 08 Apr 2009 10:51:19 -0400 Neal Becker ndbeck...@gmail.com wrote: What was wrong with this one? def demux(iterable, n): return tuple(islice(it, i, None, n) for (i, it) in enumerate(tee(iterable, n))) Nothing much, I only noticed after posting that this one handles infinite sequences too. For smallish values of n it is acceptable. P. -- http://mail.python.org/mailman/listinfo/python-list
Re: 3D plotting in a GUI
Baris Demir wrote: Stef Mientki wrote: Baris Demir wrote: Hi all, I need to develop a GUI for some scientific data processing operations and this GUI should work well with a 3D plotting module, also with NumPy and SciPy for sure. I made a search about packages but, there are plenty of these modules available. What kind of a package or a package of packages might be the best way for this work. BTW I do not want to use MayaVi. It is too much actually. What do you mean by too much actually ? What's the GUI you had in mind ? What kind of scientific data processing do you've in mind ? cheers, Stef I am quite experienced about python programming but this is going to be my first GUI design. I need to draw some 2D graphs (also capability for 3D graphs might be very delicious) and do some mathematical operations on them like adding, substracting, smoothing, integration, detecting peak points and marking them, fourier transformations and etc. on WindowsXP. And then I want to convert this python code into a .exe by using py2exe. I said Mayavi is too much for me because I thought that it would be more likeyl to have problems while using a big package like MayaVi with py2exe. Two obvious choices are wxPython + MatPlotLib and/or VPython or PyQt, depends on what license you're after. Maybe interesting to know that a number of guys are creating MatLab-like environements, search the scipy newsgroup. You can also find some m-file to numpy converters (in case you might have m-files already). And I can assure you, there are 2 packages which will give you trouble with py2exe: numpy and matplotlib. btw if you choose wxPython, download the demo first, and you might even be interested in a simpler way to create GUIs, http://mientki.ruhosting.nl/data_www/pylab_works/pw_gui_support.html good luck, Stef -- http://mail.python.org/mailman/listinfo/python-list
Re: how to get back an object from its id() value
TP wrote: If di is reliable, it seems a good solution for my initial constraint which is the impossibility to store anything but strings in my data structure. 'di' is dangerous and not reliable. When the original object is freed, then the memory address may be used by another Python object, point to an invalid Python object or some random bytes. You can easily mess up or seg fault the Python interpreter. 'di' is an evil debugging hack that may proof useful as last resort. Do *not* use anything like 'di' in production code. Christian -- http://mail.python.org/mailman/listinfo/python-list
Re: asynchronous python call
Hi, joeygartin wrote: Complete newbie, so forgive my improper use of Python terminology. I am working with Django and I have to send off a number of emails after a person has filled out a form. What I want is to make a call that goes off to form and send the emails and redirect the user to another view. I have this working now, but I noticed it is a bit slow. So I was hoping there was a way to spin off the process and redirect the user to the page while the emails are being formed and sent vs. making the page hang while it is done. You best bet would be something like Zope's asynchronous mail handler which is simply a queue Folder where you write the mail to be send and having an outside process completely independend to scan for new mail to be send out from time to time. If you want to speed up the pickup time you could have the mail sender process open a socket (UDP for example) where you can ping once you wrote out the mails to be send. Regards Tino -- http://mail.python.org/mailman/listinfo/python-list
Re: Module caching
Anyway, this person also posted on mod_python list. One of the things I highlighted there was that mod_python for some configurations is multithreaded and as such they may not be properly protecting variables if they are storing them at global scope. They haven't responded to any comments about it on mod_python list. They were also told to read: http://www.dscpl.com.au/wiki/ModPython/Articles/TheProcessInterpreter... Graham Thanks, Graham. Sorry I didn't respond -- it's crunch time here, so I was pulled off the project for a couple days to help with something else. I just didn't have time to catch up. In the end, we decided to convert everything from mod_python to CGI, which ended up getting us the functionality we were looking for. For development, MaxRequestsPerChild was already set to 1, but this didn't solve any of the variable caching issues. Aaron -- http://mail.python.org/mailman/listinfo/python-list
Re: Q: Best book for teaching
Lawrence D'Oliveiro l...@geek-central.gen.new_zealand wrote in message news:grhq75$eb...@lust.ihug.co.nz... I thought that a good introduction might be to show them how HTML works, and progress from there to embedding little bits of JavaScript. Nothing to do with Python I know, but might be a possibility. If you want to emphasize web usage, I'd be tempted to show them a bit of HTML and then introduce them to CGI-bin scripts... written in Python. Something like Django might be fun to show as well, although such full featured content management systems are really a course unto themselves. (And if you're used Python scripts on the server and played with, e.g., MySQL a little, it'll be clear that things like Django are just greatly expanded versions of what they're doing themselves.) ---Joel -- http://mail.python.org/mailman/listinfo/python-list
Computed attribute names
There are a number of things which I have been used to doing in other OO languages which I have not yet figured out how to do in Python, the most important of which is passing method names as args and inserting them into method calls. Here are two cases I have been trying to figure out for a current project. The first is passing methods to dispatcher methods. In pseudocode, something like this: def dispatcher(self,methodname): self.obj1.methodname() self.obj2.methodname() and another case is selecting behavior of an object by setting a type string, with pseudo code like this: self.IBM029 = re.compile([^acharset] self.IBM026 = re.compile([^anothercharset] self.type = IBM029 errs = self.(self.type).findall(aCardImage) I have yet to find any way to do either, although it appears I could do some of it using a long and roundabout call string using __dict__. What is the Python dialect for this sort of runtime OO? signature.asc Description: Digital signature -- http://mail.python.org/mailman/listinfo/python-list
Re: Computed attribute names
On Wed, 2009-04-08 at 19:47 +0100, Dale Amon wrote: There are a number of things which I have been used to doing in other OO languages which I have not yet figured out how to do in Python, the most important of which is passing method names as args and inserting them into method calls. Here are two cases I have been trying to figure out for a current project. The first is passing methods to dispatcher methods. In pseudocode, something like this: def dispatcher(self,methodname): self.obj1.methodname() self.obj2.methodname() The built-in getattr() function: def dispatcher(self, methodname): getattr(self.obj1, methodname)() getattr(self.obj2, methodname)() and another case is selecting behavior of an object by setting a type string, with pseudo code like this: self.IBM029 = re.compile([^acharset] self.IBM026 = re.compile([^anothercharset] self.type = IBM029 errs = self.(self.type).findall(aCardImage) Same: errs = getattr(self, self.type).findall(aCardImage) -- http://mail.python.org/mailman/listinfo/python-list
Re: Computed attribute names
Dale Amon schrieb:
There are a number of things which I have been used
to doing in other OO languages which I have not yet
figured out how to do in Python, the most important
of which is passing method names as args and inserting
them into method calls. Here are two cases I have been
trying to figure out for a current project.
The first is passing methods to dispatcher methods. In
pseudocode, something like this:
def dispatcher(self,methodname):
self.obj1.methodname()
self.obj2.methodname()
I'd say you can use:
method = getattr(self.obj1, 'methodname')
method()
It will raise AttributeError if 'methodname' is not found or the
(optional) third argument to getattr()
and another case is selecting behavior of an object by
setting a type string, with pseudo code like this:
self.IBM029 = re.compile([^acharset]
self.IBM026 = re.compile([^anothercharset]
self.type = IBM029
errs = self.(self.type).findall(aCardImage)
same here, or use a class/module-level dict like
symbol_table = {
'IBM029': re.compile([^...]),
'IBM026': re.compile([^...])
}
and symbol_table[self.type].findall(something)
cheers
Paul
--
http://mail.python.org/mailman/listinfo/python-list
--
http://mail.python.org/mailman/listinfo/python-list
Re: Computed attribute names
On Wed, Apr 08, 2009 at 09:03:00PM +0200, paul wrote: I'd say you can use: Thanks. I could hardly ask for a faster response on a HowTo than this! signature.asc Description: Digital signature -- http://mail.python.org/mailman/listinfo/python-list
Re: Q: Best book for teaching
I taught myself Python from Python Programming for the Absolute Beginner by Michael Dawson (which has been mentioned above) and with lots of help from the friendly members of this group, but there's now a free e-book titled Snake Wrangling for Kids by Jason Briggs. You can view it at http://www.briggs.net.nz/log/writing/snake-wrangling-for-kids/. There are versions for Windows, Mac and Linux, though it is focused on Python 2.x. Thomas Philips -- http://mail.python.org/mailman/listinfo/python-list
Re: Painful?: Using the ast module for metaprogramming
I see how it avoids needing to look at the parent node in general, but if we were compiling by recursively descending through the AST, then we would know whether Name's would be loads or stores by the time we got to them (we would already had to have visited an encompassing assignment or expression) Python's compiler does recursively descend. However, it is still more convenient to allow uniform processing of expressions, rather than having parameters passed down into the visitor functions. except in the case of your a = b = c expression, which I'm curious how Python handles. The natural answer is for assignment to be an expression (so b = c returns the new value of b). But Python doesn't do that, so then I'd expect we'd have some third ast.LoadAndStore() option for b, but examining ast.parse's behavior it looks like it chooses Store... No, the value of b is never read in this assignment. I'm not quite sure whether you are aware what the *actual* semantics of this assignment is; it is equivalent to tmp = c a = tmp b = tmp (so the assignment to a happens first), and neither a nor b is being read. So it's simple stores into both a and b. -Why can't orelse for ast.If and ast.While default to empty []? You want to store None? That would be a type error; orelse is specified as stmt*. So it must be a list. A list is actually what I want, an empty one. The problem is that ast.While and ast.If's constructors default to the opposite, orelse=None. Same with keywords and args for ast.Call. Admittedly, adding orelse=[] to the constructor calls isn't terribly burdensome, but it does make already obfuscated looking AST mangling code even worse. Ah, that could be fixed. Please contribute a patch. -Why can't I eval a functiondef to get back a function object? Because a definition is not an expression. You can only eval expressions. I understand that if function definitions were expressions, because of the whitespace syntax there wouldn't be a way to express an assignment to such an expression. But, why would it be problematic to let them be expressions anyway? This would be a significant change to the compiler, which would have to learn what bytecodes to compile it to. Feel free to discuss this on python-ideas. Regards, Martin -- http://mail.python.org/mailman/listinfo/python-list
Testing the new version of Psyco
hello i recently tried out this new version of psyco... http://www.voidspace.org.uk/python/weblog/arch_d7_2009_03_14.shtml#e1063 ...because of the new support for generators. the above link says To use and test generators, create preferences.py, following the instructions in setup.py - except there's nothing obvious in setup.py that refers to generators. anyway, i created a preferences.py file (with PSYCO_DEBUG = 1) and ran psycobench against python-2.5/psyco-1.6 and python-2.6/psyco-2.0 with the following results (output has been cropped slightly): # start output [benchmark]$ python2.5 psycobench.py -m time_generators time_anyall Running new timings with original psyco send call loop 1000 plain: 3.30 psyco: 3.29 ratio: 1.00 send and loop 1000 plain: 3.28 psyco: 3.27 ratio: 1.00 send just many timesplain: 1.28 psyco: 0.56 ratio: 2.29 * iterate just many times plain: 0.67 psyco: 0.57 ratio: 1.19 * call next just many times plain: 0.85 psyco: 0.63 ratio: 1.35 * all_bool_genexp plain: 2.03 psyco: 2.31 ratio: 0.88 all_bool_listcomp plain: 2.94 psyco: 1.01 ratio: 2.91 all_genexp plain: 1.71 psyco: 1.97 ratio: 0.87 all_listcompplain: 2.70 psyco: 0.73 ratio: 3.71 all_loopplain: 1.09 psyco: 0.08 ratio: 13.15 any_bool_genexp plain: 2.03 psyco: 2.45 ratio: 0.83 any_bool_listcomp plain: 2.89 psyco: 0.97 ratio: 2.99 any_genexp plain: 1.74 psyco: 1.84 ratio: 0.95 any_listcompplain: 2.65 psyco: 0.72 ratio: 3.69 any_loopplain: 1.08 psyco: 0.08 ratio: 13.10 [benchmark]$ python2.6 psycobench.py -m time_generators time_anyall Running new timings with python2.6/site-packages/psyco/_psyco.so send call loop 1000 plain: 2.85 psyco: 0.04 ratio: 67.90 send and loop 1000 plain: 2.85 psyco: 0.04 ratio: 65.00 send just many timesplain: 1.17 psyco: 0.87 ratio: 1.35 iterate just many times plain: 0.64 psyco: 0.86 ratio: 0.74 call next just many times plain: 0.77 psyco: 0.87 ratio: 0.89 all_bool_genexp plain: 1.87 psyco: 1.98 ratio: 0.95 all_bool_listcomp plain: 2.54 psyco: 0.66 ratio: 3.84 all_genexp plain: 1.69 psyco: 1.77 ratio: 0.95 all_listcompplain: 2.38 psyco: 0.52 ratio: 4.55 all_loopplain: 1.07 psyco: 0.08 ratio: 14.24 any_bool_genexp plain: 1.87 psyco: 1.99 ratio: 0.94 any_bool_listcomp plain: 2.57 psyco: 0.68 ratio: 3.76 any_genexp plain: 1.74 psyco: 1.82 ratio: 0.95 any_listcompplain: 2.47 psyco: 0.53 ratio: 4.66 any_loopplain: 1.07 psyco: 0.07 ratio: 14.65 # end output with the obvious exception of the the first two tests for psyco v2, the results (for generators) seem a little underwhelming. in fact, psyco v1 does significantly better on three of the tests (marked with an asterisk) and for the others there's not much difference. this makes me wonder whether i enabled generators properly in psyco v2 when i compiled it. has anybody else tried out this new version of psyco and got better overall results for generators? also, those first two results for v2 look really odd - what could explain the huge difference relative to the other generator tests for v2? (p.s. i re-ran the tests and got very similar results) -- Baz Walter -- http://mail.python.org/mailman/listinfo/python-list
Re: asynchronous python call
In article 637028a0-58b9-4912-896d-2b17e1341...@q16g2000yqg.googlegroups.com, joeygartin joeygar...@gmail.com wrote: I am working with Django and I have to send off a number of emails after a person has filled out a form. What I want is to make a call that goes off to form and send the emails and redirect the user to another view. I have this working now, but I noticed it is a bit slow. So I was hoping there was a way to spin off the process and redirect the user to the page while the emails are being formed and sent vs. making the page hang while it is done. The simplest solution is to create an external program and use the subprocess module to call it. You could also use fork() directly, but that's more complicated. -- Aahz (a...@pythoncraft.com) * http://www.pythoncraft.com/ ...string iteration isn't about treating strings as sequences of strings, it's about treating strings as sequences of characters. The fact that characters are also strings is the reason we have problems, but characters are strings for other good reasons. --Aahz -- http://mail.python.org/mailman/listinfo/python-list
Re: Python 3.0 online docs broken
On Wed, Apr 8, 2009 at 11:28 AM, Jim Garrison j...@acm.org wrote: Jim Garrison wrote: Ye Liu wrote: On Apr 6, 6:33 pm, Jim Garrison j...@acm.org wrote: I notice the online docs (at docs.python.org/3.0/index.html) were updated today. It seems some of the top-level pages, like Tutorial, Using Python, Language Reference are truncated after the first few paragraphs. Yea, same here. Hope it's going to be fixed soon. Still broken. I've emailed webmaster(at)python.org I'm still seeing only stubs for many of the doc pages at docs.python.org. For example http://docs.python.org/3.0/tutorial/index.html This page stops at the sentence The Glossary is also worth going through. whereas it used to be followed by a hyperlinked table of contents for all the tutorial pages. I emailed the webmaster but have received no response. Am I the only one seeing this? Nope. I have the same problem. -- http://mail.python.org/mailman/listinfo/python-list -- http://mail.python.org/mailman/listinfo/python-list
Re: named pipe and Linux
Cameron Simpson c...@zip.com.au wrote: On 07Apr2009 10:08, akineko akin...@gmail.com wrote: | I'm trying to use named pipes to fuse a Python program and a C | program. | One side creates pipes using os.mkfifo() and both sides use the same | named pipes (one side reads, another side writes). The read side uses | select.select() to wait for incoming messages and read the message | when select.select() says it is ready. | The length of the message is unknown to the read side. That's a serious flaw in the message protocol. | I cannot use file.read() because it will block waiting for an EOF. | I cannot use file.readline() because how many lines have arrived is | unknown. | So, I needed to use os.read() with the exact number of characters to | read. No! You should use os.read() with the maximum size of a message. It _should_ return with the number of bytes in the message, provided the C program writes messages with a single OS-level write() call. No! That's still broken. You can't know if the writer has managed to write one or several messages onto the pipe. And if the messages are large, you aren't guaranteed that the OS won't split up the data into multiple segments that only become available to the reader one or a few at a time. You *need* to use a protocol where it is possible to determine the message boundaries. You can do that by: - Using messages of a fixed size. - Terminate each message with an octet sequence that cannot occur within a message. For example, a linefeed without a backslash before it (and you would probably want a way to escape the backslash, in case you want to end a message with a backslash). - Have small header of a fixed size at the start of each message, that includes the length of the message in octets. -- Thomas Bellman, Lysator Computer Club, Linköping University, Sweden Life IS pain, highness. Anyone who tells ! bellman @ lysator.liu.se differently is selling something. ! Make Love -- Nicht Wahr! -- http://mail.python.org/mailman/listinfo/python-list
Re: Some test fail on my new Python 2.6
Hello again, /usr/local/lib is in /etc/ld.so.conf. The files are real. However, creating symlinks in /usr/lib targeting the libraries in /usr/local/lib, then recompiling, solved the tkinter problem. So, the conclusion is that only /usr/lib is consulted for the tcl/tk libraries. multiprocessing - do I need it? Probably not. I can fork() a new process, so I can manage. I don't know what am I loosing without multiprocessing. socket was solved as suggested, by adding the host name in /etc/hosts, like this: 127.0.0.1 localhost dsr-1 sys doesn't fail anymore after recompilation (have no clue why). htttpservers is still failing the same. Everything is done as root. I'll move on with make install. Thanks for your help; I'm progressing :-) SxN __ Instant Messaging, free SMS, sharing photos and more... Try the new Yahoo! Canada Messenger at http://ca.beta.messenger.yahoo.com/ -- http://mail.python.org/mailman/listinfo/python-list
Re: Q: Best book for teaching
On Mon, 06 Apr 2009 07:37:19 -0700, grkuntzmd wrote: What would be a good book to use as the text for the course? Python Programming: An Introduction to Computer Science Franklin, Beedle Associates, by little Johny Zelle. Accept no substitues! Jim -- http://mail.python.org/mailman/listinfo/python-list
Re: extract Infobox contents
On Wed, 2009-04-08 at 01:57 +0100, Rhodri James wrote:
On Tue, 07 Apr 2009 12:46:18 +0100, J. Clifford Dyer
j...@sdf.lonestar.org wrote:
On Mon, 2009-04-06 at 23:41 +0100, Rhodri James wrote:
On Mon, 06 Apr 2009 23:12:14 +0100, Anish Chapagain
anishchapag...@gmail.com wrote:
Hi,
I was trying to extract wikipedia Infobox contents which is in format
like given below, from the opened URL page in Python.
{{ Infobox Software
| name = Bash
[snip]
| latest release date= {{release date|mf=yes|2009|02|20}}
| programming language = [[C (programming language)|C]]
| operating system = [[Cross-platform]]
| platform = [[GNU]]
| language = English, multilingual ([[gettext]])
| status = Active
[snip some more]
}} //upto this line
I need to extract all data between {{ Infobox ...to }}
[snip still more]
You end up with 'infoboxes' containing a list of all the infoboxes
on the page, each held as a list of the lines of their content.
For safety's sake you really should be using regular expressions
rather than 'startswith', but I leave that as an exercise for the
reader :-)
I agree that startswith isn't the right option, but for matching two
constant characters, I don't think re is necessary. I'd just do:
if '}}' in line:
pass
Then, as the saying goes, you only have one problem.
That would be the problem of matching lines like:
| latest release date= {{release date|mf=yes|2009|02|20}}
would it? :-)
That's the one.
A quick bit of timing suggests that:
if line.lstrip().startswith(}}):
pass
is what we actually want.
Indeed. Thanks.
--
http://mail.python.org/mailman/listinfo/python-list
str object is not callable error
HIi everyone. i was using python/c api to call a python function from c and I know the name of the function which i want to call.Is there any way to do that?? This is the method i tried... for eg:This is the python function i wants to call. def add(x): ... return x+10 This is my code in C: PyObject *result = NULL; int arg; PyObject *arglist; arg = 123; my_callback = add; arglist = Py_BuildValue((i), arg); result = PyObject_CallObject(my_callback, arglist); Py_DECREF(arglist); return result; I was getting a error like str object is not callable.From the error i came to know that i was assigning add as a string which caused this error.Then how to make it a callable object?? Regards Venkat -- http://mail.python.org/mailman/listinfo/python-list
Re: more fun with iterators (mux, demux)
On Wed, Apr 8, 2009 at 1:21 PM, pataphor wrote: On Wed, 08 Apr 2009 10:51:19 -0400 Neal Becker wrote: What was wrong with this one? def demux(iterable, n): return tuple(islice(it, i, None, n) for (i, it) in enumerate(tee(iterable, n))) Nothing much, I only noticed after posting that this one handles infinite sequences too. For smallish values of n it is acceptable. I assume that smallish values of n refers to the fact that itertools.tee places items into every generator's internal deque, which islice then skips over, whereas your version places items only into the deque of the generator that needs it. However, for small n, the tee-based solution has the advantage of having most of the work done in C instead of in Python generator functions; in my limited benchmarking, the point where your version becomes faster is somewhere around n=65. -Miles -- http://mail.python.org/mailman/listinfo/python-list
nested looping
So I'm trying to see whats the cleanest way to do this: I have a checklist = [ax, bx, by, cy ..] (a combination of a,b,c with x and y, either both on one) allist = [a,b,c,] xlist = [x, y, ..] now I wanna loop through alist and xlist and see if the combination exists in checklist so something like, for alpha in alist: for xy in xlist: if alpha+xy not in checklist: missing.append(alpha) now the problem is I want to include alpha in missing list only if none of the combinations from xlist with alpha are in checklist. The above will exclude the possibility where ax doesn't exist but ay or az does exist. Hope There is a cleaner way to accomplish this. Thanks in advance, PK -- http://mail.python.org/mailman/listinfo/python-list
Character strings / Python 3.0 C API
Hi everybody,
I'm doing some experiments with the python 3.0 C API, and I'm having
some problems for obtaining character strings. In python 2.X APIs, a
function called PyString_AsString was available. This function
provided a C string (char*) given a PyObject. But, in python 3.0 API
there is no such a function, and they mention that it has been
substituted by PyUnicode* functions. The issue is that I still don't
get how to use these functions to obtain char strings in C!
This is one of the things I try to do:
PyThreadState* state = PyThreadState_GET();
PyInterpreterState* interp = state-interp;
int numModules = PyDict_Size(interp-modules);
PyObject* moduleKeys = PyDict_Keys(interp-modules);
int idx=0;
for(idx=0; idxnumModules; idx++)
{
PyObject* key = PyList_GetItem(moduleKeys,idx);
PyObject* module = PyDict_GetItem( interp-modules, key );
char* theKeyName =
PySys_WriteStdout(Module '%s'\n, theKeyName);
}
I was not able to obtain theKeyName, knowing that the key PyObject
is in fact a unicode string containing the character string I want...
Could anybody help me? How can I, in general, obtain char* strings
from a corresponding PyObject? What should I use for ?
Thank you very much in advance,
Cheers
RC
--
http://mail.python.org/mailman/listinfo/python-list
Re: genetic algorithms in Python?
Esmail wrote: Hello, Anyone using Python for coding up genetic algorithms? If so, would you share your favorite modules/libraries/tools? Search 'Python genetic algorithm' on Google or elsewhere. -- http://mail.python.org/mailman/listinfo/python-list
Re: genetic algorithms in Python??
R. David Murray wrote: Esmail esmail...@gmail.com wrote: Hello Mohammed, Yes, that would great. While I am comfortable with GAs, I'm still rather inexperienced with Python so seeing some implementation examples would be very useful. A google for 'python genetic algorithms' turns up a number of interesting hits. Agreed .. I did that and came up with a number of hits, but the problem :-) with Python is a plethora of choices, so I wasn't quite sure which of the finds might be the most promising/useful. Nothing like a testimony from someone who uses or has used a tool. I also remember seeing at least one package announced on python-announce that referred to genetic algorithms, so you might check the archives of that mailing list as well. Yes, that's a good idea, thanks, Esmail -- http://mail.python.org/mailman/listinfo/python-list
Re: genetic algorithms in Python?
Terry Reedy wrote: Esmail wrote: Hello, Anyone using Python for coding up genetic algorithms? If so, would you share your favorite modules/libraries/tools? Search 'Python genetic algorithm' on Google or elsewhere. Hi Terry, I did that first, and I came up with a number of hits. The problem with Python is that there's so much available and it's sometimes hard to decide what to select, so I was looking for some folks who had use some of the tools and could share their experiences. Esmail ps: the problem is a good thing to have all things considered :-) -- http://mail.python.org/mailman/listinfo/python-list
Re: Character strings / Python 3.0 C API
PyObject* key = PyList_GetItem(moduleKeys,idx); PyObject* module = PyDict_GetItem( interp-modules, key ); char* theKeyName = PySys_WriteStdout(Module '%s'\n, theKeyName); } I was not able to obtain theKeyName, knowing that the key PyObject is in fact a unicode string containing the character string I want... Use PyUnicode_AsUTF8String. Could anybody help me? How can I, in general, obtain char* strings from a corresponding PyObject? What should I use for ? In general, this is much more difficult. If the object is an integer (say), or a file object - what is the char* that you want to get? You would need to call PyObject_Str first, getting str() (or repr()) of the object, and then use PyUnicode_AsUTF8String (releasing the _Str result afterwards). Regards, Martin -- http://mail.python.org/mailman/listinfo/python-list
Re: nested looping
PK wrote: So I'm trying to see whats the cleanest way to do this: I have a checklist = [ax, bx, by, cy ..] (a combination of a,b,c with x and y, either both on one) Since you will be repeatedly looking for items in checklist, I suggest making it a set instead. allist = [a,b,c,] xlist = [x, y, ..] now I wanna loop through alist and xlist and see if the combination exists in checklist so something like, for alpha in alist: for xy in xlist: if alpha+xy not in checklist: missing.append(alpha) This will append alpha multiple times. Not what you want. now the problem is I want to include alpha in missing list only if none of the combinations from xlist with alpha are in checklist. for xy in xlist: if alpha+xy in checklist: break else: missing.append(alpha) # or missing.add(alpha) if missing a set tjr -- http://mail.python.org/mailman/listinfo/python-list
Re: more fun with iterators (mux, demux)
[Miles] I assume that smallish values of n refers to the fact that itertools.tee places items into every generator's internal deque, which islice then skips over, whereas your version places items only into the deque of the generator that needs it. The pure python equivalent listed in the docs uses separate deques for each subiterator, but the actual C implementation of itertools.tee() only has one internal deque that is shared by all of the sub-iterators. Raymond -- http://mail.python.org/mailman/listinfo/python-list
Re: Character strings / Python 3.0 C API
Sorry but it did not help... I tried this: PyObject* key = PyList_GetItem(moduleKeys,idx); char* theKeyName = PyUnicode_AsUTF8String( key ); And this, just in case: PyObject* key = PyList_GetItem(moduleKeys,idx); char* theKeyName = PyUnicode_AsUTF8String( PyObject_Str (key) ); (Although it should work in the first case since key is suposed to be a string already, the module name). In all the cases, I obtained an empty string when using theKeyName: PySys_WriteStdout(Module '%s'\n, theKeyName); The issue is that all PyUnicode* functions are returning PyObjects. PyString_AsString return value was char*. Is there any real equivalent of this function? Thanks again. Best regards, RC On 8 abr, 23:35, Martin v. Löwis mar...@v.loewis.de wrote: PyObject* key = PyList_GetItem(moduleKeys,idx); PyObject* module = PyDict_GetItem( interp-modules, key ); char* theKeyName = PySys_WriteStdout(Module '%s'\n, theKeyName); } I was not able to obtain theKeyName, knowing that the key PyObject is in fact a unicode string containing the character string I want... Use PyUnicode_AsUTF8String. Could anybody help me? How can I, in general, obtain char* strings from a corresponding PyObject? What should I use for ? In general, this is much more difficult. If the object is an integer (say), or a file object - what is the char* that you want to get? You would need to call PyObject_Str first, getting str() (or repr()) of the object, and then use PyUnicode_AsUTF8String (releasing the _Str result afterwards). Regards, Martin -- http://mail.python.org/mailman/listinfo/python-list
Re: Character strings / Python 3.0 C API
The issue is that all PyUnicode* functions are returning PyObjects. PyString_AsString return value was char*. Is there any real equivalent of this function? Ah, right. PyString_AsUTF8String returns a bytes object, to which you need to apply PyBytes_AsString to. At the end, you need to decref the bytes object. Regards, Martin -- http://mail.python.org/mailman/listinfo/python-list
Re: nested looping
On Apr 8, 2:15 pm, PK superp...@gmail.com wrote:
So I'm trying to see whats the cleanest way to do this:
I have a
checklist = [ax, bx, by, cy ..] (a combination of a,b,c with x and y,
either both on one)
allist = [a,b,c,]
xlist = [x, y, ..]
now I wanna loop through alist and xlist and see if the combination
exists in checklist
so something like,
for alpha in alist:
for xy in xlist:
if alpha+xy not in checklist:
missing.append(alpha)
now the problem is I want to include alpha in missing list only if
none of the combinations from xlist with alpha are in checklist.
The above will exclude the possibility where ax doesn't exist but ay
or az does exist.
Hope There is a cleaner way to accomplish this.
Thanks in advance,
PK
That code doesn't look too bad. It is fairly readable. There are
several ways to accomplish this though. If you aren't interested in
duplicate values or order then sets would be a good option.
something like this:
missing = set(alpha + xy for alpha in alist for xy in xlist).difference
(checklist)
if you are using 2.6 you could also make use of the product generator
in itertools:
from itertools import product
missing = set(''.join(p) for p in product(alist, xlist)).difference
(checklist)
If you could adapt your code to use tuples instead of strings you
could do it like this:
missing = set(product(alist, xlist)).difference(checklist)
Matt
--
http://mail.python.org/mailman/listinfo/python-list
Re: Character strings / Python 3.0 C API
Thank you very much for your help Martin, now I got it. Cheers, RC On 9 abr, 00:05, Martin v. Löwis mar...@v.loewis.de wrote: The issue is that all PyUnicode* functions are returning PyObjects. PyString_AsString return value was char*. Is there any real equivalent of this function? Ah, right. PyString_AsUTF8String returns a bytes object, to which you need to apply PyBytes_AsString to. At the end, you need to decref the bytes object. Regards, Martin -- http://mail.python.org/mailman/listinfo/python-list
Decompression with zlib
Hello, I'm trying to do compression/decompression of stuff with zlib, and I just don't get it... Here is an example. I assume that dec should be a, but it isn't. dec turns out to be an empty string, and I don't understand why... === import zlib compressor = zlib.compressobj(6) # level decompressor = zlib.decompressobj() # wbits cmpr = compressor.compress(a) print compressed, len(cmpr) dec = decompressor.decompress(cmpr) print decompressed, len(dec) # unconsumed tail and unused data print decompressor.unconsumed_tail, decompressor.unconsumed_tail ##print decompressor.unused_data, decompressor.unused_data dec += decompressor.flush() print after flushing, len(dec) === Any help is appreciated. Emma -- http://mail.python.org/mailman/listinfo/python-list
Re: nested looping
Quoting PK superp...@gmail.com: So I'm trying to see whats the cleanest way to do this: I have a checklist = [ax, bx, by, cy ..] (a combination of a,b,c with x and y, either both on one) allist = [a,b,c,] xlist = [x, y, ..] [...] now the problem is I want to include alpha in missing list only if none of the combinations from xlist with alpha are in checklist. This is untested: for alpha in alist: for xy in xlist: if alpha+xy in checklist: break else: missing.append(alpha) (note that the else is for the for, not the if) You could also try the any/all functions from python2.5: for alpha in alist: if not any(alpha + xy in checklist for xy in xlist): missing.append(alpha) Or the really not recommended one-liner: missing = [alpha for alpha in alist if not any(alpha + xy in checklist for xy in xlist)] (remember, all of this is untested) -- Luis Zarrabeitia Facultad de Matemática y Computación, UH http://profesores.matcom.uh.cu/~kyrie -- Participe en Universidad 2010, del 8 al 12 de febrero de 2010 La Habana, Cuba http://www.universidad2010.cu -- http://mail.python.org/mailman/listinfo/python-list
