🌐 Mailman 3 December 2004 - Python-list - python.org

Re: copying classes?
by aleaxit＠yahoo.com Dec. 31, 2004

Dec. 31, 2004

harold fellermann <harold.fellermann(a)upf.edu> wrote: ... > > I always think that a well designed object should have a copyme method. > > :=) That would be __copy__ or __deepcopy__, but the __getstate__ / __setstate__ approach is often preferable. > take a look at the __setstate__ and __getstate__ documentation of copy > (e.g. pickle) -- with them you can customize the copying task. Anyway, > they work only on instance but not on class objects :( They should, if you put them in the class of the class -- the metaclass. >>> class mec(type): ... def __copy__(cls): ... return mec('copyof'+cls.__name__, cls.__bases__, dict(vars(cls))) ... >>> class foo: ... __metaclass__ = mec ... >>> bar = copy.copy(foo) >>> bar.__name__ 'copyoffoo' >>> Alex

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py2app on Mac OS X 10.3
by Austin Dec. 31, 2004

Dec. 31, 2004

""" Minimal setup.py example, run with: % python setup.py py2app """ from distutils.core import setup import py2app setup( app = ['main.py'], ) That is a sample code of wiki. I have a file 'main.py' and several sub-folders. After I execute 'pythonw setup.py py2exe', I see 2 folders, 'dist' & 'build' which is the same as py2exe. I open the 'dist' folder and see a file 'main'. Then I double-click the 'main' and appeared the error message. 'IOError:[Errno 2] No such file or directory: '/user/austin/Desktop/disk/main.app/Contents/Resources/log/eventlog.xml I feel so wildered because 'main.app' should be a file not a folder. I was wondering if some extra codes needed by setup.py Could anyone give me an advice? Thanks a lot.

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Re: copying classes?
by It's me Dec. 31, 2004

Dec. 31, 2004

I would not think that a generic deepcopy would work for all cases. An object can be as simple as a number, for instance, but can also be as complex as the universe. I can't imagine anybody would know how to copy a complex object otherthen the object itself. I always think that a well designed object should have a copyme method. :=) "Bob Van Zant" <bvanzant(a)asyncfs.com> wrote in message news:mailman.8563.1104346385.5135.python-list@python.org... > Ha. I just read down to the bottom of pyDoc page. > > "This version does not copy types like module, class, function, method, > nor stack trace, stack frame, nor file, socket, window, nor array, nor > any similar types." > > However, I actually tried it and it worked at least in the simple case: > >>> class x: > ... def __init__(self): > ... self.y = 1 > ... > >>> obj = x() > >>> obj.y > 1 > >>> > >>> import copy > >>> z = copy.deepcopy(obj) > >>> z.y > 1 > >>> obj.y = 4 > >>> obj.y > 4 > >>> z = copy.deepcopy(obj) > >>> z.y > 4 > > -Bob > > On Wed, 2004-12-29 at 10:42 -0800, Bob Van Zant wrote: > > copy.deepcopy() should do the trick. This URL answers a little bit of > > your question about the difficulties in copying "complex" data > > structures. > > > > http://pydoc.org/2.3/copy.html > > > > -Bob > > > > On Wed, 2004-12-29 at 19:29 +0100, harold fellermann wrote: > > > Hi all, > > > > > > In the documentation of module 'copy' it is said that "This version > > > does not copy types like module, class, function, method, stack trace, > > > stack frame, file, socket, window, array, or any similar types." > > > > > > Does anyone know another way to (deep)copy objects of type class? What > > > is special about the objects of these types that they cannot be easily > > > copied? > > > > > > Any help appreciated, > > > > > > - harold - > > > > > > > > > -- > > > I like pigs. Dogs look up to us. Cats look down to us. > > > Pigs treat us as equal. > > > -- Winston Churchill > > > > > >

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Re: The Industry choice
by Steve Holden Dec. 31, 2004

Dec. 31, 2004

Premshree Pillai wrote: > On 30 Dec 2004 08:58:36 -0800, Sridhar R <sridharinfinity(a)gmail.com> wrote: > >>>From technical point of view, I could not understand the the reasoning >>behind using Java in major companies. Sure that Python, is used in >>some, but still Java is considered as a sure-job language. > > > It certainly is not because Python is bad or something. Organizations > typically take lot of time to change -- be it technology or office > furniture. > > We either need time for folks to accept dynamic, "scripting" > languages, or a lot of "modern" language programmers need to gang up > against managers and stuff. :) > > [...] Right, what have the managers ever done for us? regards Steve -- Steve Holden http://www.holdenweb.com/ Python Web Programming http://pydish.holdenweb.com/ Holden Web LLC +1 703 861 4237 +1 800 494 3119

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RE: Is there a better way of listing Windows shares other than us ing "os.listdir"
by Doran_Dermot＠emc.com Dec. 31, 2004

Dec. 31, 2004

Hi David, Thanks for the bit of code on finding shares! I'd been using something a bit different (win32com.client stuff) but your code looks better. I've found that "win32file.FindFilesIterator" (suggested to me by another person on this mailing list) allows the gui to remain responsive. Using the same code to execute the "os.listdir" hangs the gui! I've been using the wx.PostEvent and Python threading objects to implement multi-threading. Works very well! The wxPython demo illustrates the use of wx.PostEvent and Python multi-threading extremely well. Thanks again for your help! Dermot. -----Original Message----- From: python-list-bounces+doran_dermot=emc.com(a)python.org [mailto:python-list-bounces+doran_dermot=emc.com@python.org] On Behalf Of David Bolen Sent: 30 December 2004 17:39 To: python-list(a)python.org Subject: Re: Is there a better way of listing Windows shares other than using "os.listdir" Doran_Dermot(a)emc.com writes: > I'm currently using "os.listdir" to obtain the contents of some slow Windows > shares. I think I've seen another way of doing this using the win32 library > but I can't find the example anymore. Do you want the list of files on the shares or the list of shares itself? If the files, you can use something like FindFiles, but I don't expect it to be that much faster just to obtain directory names (likely the overhead is on the network). If you just want a list of shares, you could use NetUseEnum, which should be pretty speedy. (FindFiles is wrapped by win32api, and NetUseEnum by win32net, both parts of the pywin32 package) Here's a short example of displaying equivalent output to the "net use" command: - - - - - - - - - - - - - - - - - - - - - - - - - import win32net status = {0 : 'Ok', 1 : 'Paused', 2 : 'Disconnected', 3 : 'Network Error', 4 : 'Connected', 5 : 'Reconnected'} resume = 0 while 1: (results, total, resume) = win32net.NetUseEnum(None, 1, resume) for use in results: print '%-15s %-5s %s' % (status.get(use['status'], 'Unknown'), use['local'], use['remote']) if not resume: break - - - - - - - - - - - - - - - - - - - - - - - - - Details on the the arguments to NetUseEnum can be found in MSDN (with any pywin32 specifics in the pywin32 documentation). > My main problem with using "os.listdir" is that it hangs my gui application. > The tread running the "os.listdir" appears to block all other threads when > it calls this function. Yes, for a GUI you need to keep your main GUI thread always responsive (e.g., don't do any blocking operations). There are a number of alternatives to handling a long processing task in a GUI application, dependent on both the operation and toolkit in use. For wxPython, http://wiki.wxpython.org/index.cgi/LongRunningTasks covers several of the options (and the theory behind them is generally portable to other toolkits although implementation will change). -- David -- http://mail.python.org/mailman/listinfo/python-list

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Re: Securing a future for anonymous functions in Python
by John Roth Dec. 31, 2004

Dec. 31, 2004

"Ian Bicking" <ianb(a)colorstudy.com> wrote in message news:mailman.8620.1104433674.5135.python-list@python.org... > John Roth wrote: >> The syntax I prefer (and I don't know if it's actually been >> suggested before) is to use braces, that is { and }. >> >> In other words, an anonymous function looks like: >> {p1, p2, p3 | >> stmt1 >> stmt2 >> } > > What's the advantage of something like that over the non-anonymous > equivalent: > > def some_func(p1, p2, p3): > stmt1 > stmt2 > > I appreciate some of the motivation, but merely avoiding giving something > a name doesn't seem like a laudible goal. Actually, it is a laudable goal. It's always easier to understand something when it's right in front of your face than if it's off somewhere else. This, of course, trades off with two other forces: avoiding repetition and making the whole thing small enough to understand. So the niche is small, single use functions. The problem with lambdas is that they're restricted to one expression, which is too small. Languages that are designed with anonymous functions in mind use them very heavily. Smalltalk is the standard example, and it's also one of the major (possibly the only) attraction Ruby has over Python. Python isn't designed that way, which restricts their utility to a much smaller niche than otherwise. > The one motivation I can see for function expressions is callback-oriented > programming ... Well, that's true, but that's a very global statement: when you pass a function into another routine, it's essentially a callback. ... > Function expressions could get really out of hand, IMHO, and could easily > lead to twenty-line "expressions". That's aesthetically incompatible with > Python source, IMHO. Anything can get out of hand; there's no way of legislating good style without restricting the language so much that it becomes unusable for anything really interesting. Even then it doesn't work: see COBOL as a really good example of good intentions gone seriously wrong. Have you ever programmed in a language that does use anonymous functions extensively like Smalltalk? John Roth > > -- > Ian Bicking / ianb(a)colorstudy.com / http://blog.ianbicking.org

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Urgently need Elecronic version of book:Python Network programming by John Goerz
by mch2k2 Dec. 31, 2004

Dec. 31, 2004

Hello All I have just started working on Pyhton. I need urgent help regarding Python Network Programming. I want the elctronic version of the Book: Foundations of Python Network programming by John Goerzen. If anybody among you have that please forward at my mailID. Thank you in advance. Manjeet Chaudhary

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Re: Securing a future for anonymous functions in Python
by bokr＠oz.net Dec. 31, 2004

Dec. 31, 2004

On Thu, 30 Dec 2004 23:28:46 +1000, Nick Coghlan <ncoghlan(a)iinet.net.au> wrote: >GvR has commented that he want to get rid of the lambda keyword for Python 3.0. >Getting rid of lambda seems like a worthy goal, but I'd prefer to see it dropped >in favour of a different syntax, rather than completely losing the ability to >have anonymous functions. > >Anyway, I'm looking for feedback on a def-based syntax that came up in a recent >c.l.p discussion: >http://boredomandlaziness.skystorm.net/2004/12/anonymous-functions-in-pytho… > Nit: You didn't try the code you posted ;-) >>> funcs = [(lambda x: x + i) for i in range(10)] >>> >>> def incrementors(): ... for i in range(10): ... def incrementor(x): ... return x + i ... yield incrementor ... >>> #funcs = list(incrementors) ... funcs2 = list(incrementors()) >>> >>> for f in funcs: print f(0), ... 9 9 9 9 9 9 9 9 9 9 >>> for f in funcs2: print f(0), ... 9 9 9 9 9 9 9 9 9 9 This is an easy trap to fall into, so if the new lambda-substitute could provide a prettier current-closure-variable-value capture than passing a dummy default value or nesting another def and passing the value in, to provide a private closure for each, that might be something to think about. IMO an anonymous def that exactly duplicates ordinary def except for leaving out the function name and having a local indentation context would maximize flexibility and also re-use of compiler code. People could abuse it, but that's already true of many Python features. >From your web page: ---- def either(condition, true_case, false_case): if condition: return true_case() else: return false_case() print either(A == B, (def "A equals B"), (def "A does not equal B")) either(thefile, (def thefile.close()), (def 0)) ---- I'd rather see (:something) than (def something) for this special case, but the full-fledged anonymous def would spell it thus: print either(A == B, (def():return "A equals B"), (def(): return "A does not equal B")) either(thefile, (def(): return thefile.close()), (def(): return 0)) BTW, funcs = [(lambda x: x + i) for i in range(10)] might be spelled funcs = [(def(x, i=i): return x + i) for i in range(10)] or optionally funcs = [( def(x, i=i): return x + i ) for i in range(10)] or funcs = [(def(x, i=i): return x + i) for i in range(10)] or funcs = [(def(x, i=i): return x + i) for i in range(10)] or funcs = [def(x, i=i): return x + i for i in range(10)] or funcs = [ def(x, i=i): return x + i for i in range(10)] and so on. (the def defines the indentation base if the suite is indented, and the closing ')' terminates the anonymous def explicitly, or a dedent to the level of the def or less can do it, as in the last two examples). This one (def f(a) + g(b) - h(c) from (a, b, c)) would be spelled (if I undestand your example) (def(a, b, c): return f(a)+g(b)+h(c)) which seems to me familiar and easy to understand. BTW, there are old threads where this and other formats were discussed. I am still partial to the full anonymous def with nesting indentation rules. Syntactic sugar could be provided for useful abbreviations (that could possibly be expanded by the tokenizer -- re which possibilities I haven't seen any discussion than my own recent post, BTW), but I'd like the full capability. Regards, Bengt Richter

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Unicode entries on sys.path
by Thomas Heller Dec. 31, 2004

Dec. 31, 2004

I was trying to track down a bug in py2exe where the executable did not work when it is in a directory containing japanese characters. Then, I discovered that part of the problem is in the zipimporter that py2exe uses, and finally I found that it didn't even work in Python itself. If the entry in sys.path contains normal western characters, umlauts for example, it works fine. But when I copied some japanese characters from a random web page, and named a directory after that, it didn't work any longer. The windows command prompt is not able to print these characters, although windows explorer has no problems showing them. Here's the script, the subdirectory contains the file 'somemodule.py', but importing this fails: import sys sys.path = [u'\u5b66\u6821\u30c7xx'] print sys.path import somemodule It seems that Python itself converts unicode entries in sys.path to normal strings using windows default conversion rules - is this a problem that I can fix by changing some regional setting on my machine? Hm, maybe more a windows question than a python question... Thanks, Thomas

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Re: python versions of perl modules
by mfuhr＠fuhr.org Dec. 31, 2004

Dec. 31, 2004

"Earl Eiland" <eee(a)nmt.edu> writes: > I need to process some tcpdump files. PERL has Net::Pcap and > NetPacket, but I would rather work in PYTHON. Do PYTHON equivialnts > of these two modules exist? Google is your friend. http://www.google.com/ Search for words like "python", "pcap", "packet", and other terminology related to what you're trying to do. -- Michael Fuhr http://www.fuhr.org/~mfuhr/

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