🌐 Mailman 3 December 2003 - Python-list - python.org

Re: position in a for loop?
by castor＠snafu.de Dec. 31, 2003

Dec. 31, 2003

you may want to have a look @ http://aspn.activestate.com/ASPN/Cookbook/Python/Recipe/204297, where it is said that 'the interpreter creates a secret name that only exists while the list is being built. That name is (usually) "_[1]", and it refers to the bound method "append" of the list.'. for your specific problem, the enumerate() solution is probably all that you need; for other cases (such as checking whether a certain value is already a member of the list), this solution may come in handy. for example, in order to get a non-repetitive string with all the characters found in a given text, you could say print ''.join( [ x for x in 'my words are repetitive' if x not in locals()['_[1]'].__self__ ] ) hope that helps, _wolf

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Try except - bug?
by 9974331＠cvm.qc.ca Dec. 31, 2003

Dec. 31, 2003

Hi, I have a problem with try except : example ============ try: print "bou!" raise "ha!" except: try: fileDest.close() except NameError: print "error" except: import traceback traceback.print_exc(file=sys.stdout) ============ If I run this example alone, I have no problem : result ============ bou! error ============ but I can't understand why doesn't work in my program : http://www.cvm.qc.ca/9974331/Temp/crypte.py (too long for a copy and paste) (note : it's at line 353) (note : the language of this program is in french, sorry) when I run my program, I have this error : ============ Traceback (most recent call last): File "C:\Documents and Settings\Assembleur_Man\Bureau\Crypte.py", line 355, in crypte fileDest.close() NameError: global name 'fileDest' is not defined ============ but I know that 'fileDest' is not always defined but I put this line in a try-except!? :-( :-S Askari

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Try - Except : ignored!
by 9974331＠cvm.qc.ca Dec. 31, 2003

Dec. 31, 2003

Hi, In my program (too long for cut-paste) : http://www.cvm.qc.ca/9974331/Temp/crypte.py When I run and click on the button "Crypter!", a thread is run for the method "def crypte():" (line 118). After, because the field "txtCode" is blank, I raise a error (line 136). The code continu in the except at line 353. In this except block, Python ignore (I don't know how!) one of two "try - except" (line : 354-360 or 362-365) and raise a error and go out of try-except (but it's in a try except!). When I run my code with no change, this error come : ============ Traceback (most recent call last): File "C:\Documents and Settings\Assembleur_Man\Bureau\Crypte.py", line 363, in crypte os.remove(destination) OSError: [Errno 2] No such file or directory: '' ============ and if I remove the second try-except (lines 362-365), I have this error message : ============ Traceback (most recent call last): File "C:\Documents and Settings\Assembleur_Man\Bureau\Crypte.py", line 355, in crypte fileDest.close() NameError: global name 'fileDest' is not defined ============ Askari Note : I try my code with python 2.3.3, 2.3.2 and 2.2.3. I have always this bug.

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Re: RELEASED: allout-vim 031229
by Samuel Walters Dec. 31, 2003

Dec. 31, 2003

On Mon, 29 Dec 2003 21:56:19 -0500, François Pinard wrote: > Hi, my Python and Vim friends. > > Here is the initial release of `allout-vim'! :-) Grab it from: > > http://fp-etc.progiciels-bpi.ca/archives/allout-vim-031229.tgz > > The Allout file format is (yet another) legible representation of the > synoptic structure of a textual document. Emacs support for Allout files > is already standard, as an application of fold editing. This tool eases > the handling of Allout files from within a Python-enabled Vim. Is there an descriptive web page for this tarball? Sam Walters

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Re: 'inverting' a dict
by Irmen de Jong Dec. 31, 2003

Dec. 31, 2003

Jeff Epler wrote: > Does this listcomp give the right result? > dict([(v, k) for k, vs in original.iteritems() for v in vs]) Yes it does, and it's even more concise than Yermat's solution dict([(v,k) for k in d.iterkeys() for v in d[k]]) because it avoids a dict lookup every loop cycle. Thanks Jeff! --Irmen

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Re: Tkinter
by Marijan Tadin Dec. 31, 2003

Dec. 31, 2003

try googling with: tkinter tutorial the first result is: http://www.pythonware.com/library/tkinter/introduction/ Marijan Tadin "km" <km(a)mrna.tn.nic.in> wrote in message news:mailman.68.1072855330.8134.python-list@python.org... > Hi all, > I am in need of some sample scripts which cover vital issues of starting Tkinter with Python. Can somebody provide me with such links ? > > thanks in advance, > > regards, > KM >

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Re: position in a for loop?
by Pierre Quentel Dec. 31, 2003

Dec. 31, 2003

With a combination of enumerate and list comprehensions : >>> food=['linguine','Spam','clams','Spam','steak'] >>> [ i for i,v in enumerate(food) if v=='Spam' ] [1, 3] @+ Pierre

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Python on Max osx and tkinter
by Ralf Wieseler Dec. 31, 2003

Dec. 31, 2003

Hello! I'm quite new to Python. I wrote some little scripts using the "import from tkinter" Statemant that work well on Windows and Linux. but if i try to execute them in my Powerbook with Mac OSX 10.2.8 i get only Errors. I imorted the TKinter Module with the Package Manager of MacPython 2.3 but it doesn't work. My Macphython has no idea of TKinter. Whats wrong? Thanks for any help! Greetz Ralf

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Is Python Mac Centric???
by hokieghal99 Dec. 31, 2003

Dec. 31, 2003

While trying to learn more about Python's standard modules, I noticed that there are *a lot* of Mac only modules... more so than Unix and Windows specific modules combined. Is there a reason for this? I am familiar with the Windows extensions by Mr. Hammond and wonder if they'll ever become apart of the official Python distribution. It looks as if something similar already exists for Macs with all these Mac only modules. Why is this? Also, I've noticed that OSX 10.3 comes with Python 2.3 installed, but that Windows XP does not. Python installation is much more cumbersome on Windows. The user has to dl Python and then Mr. Hammond's extensions to get up to speed with the new Macs out of the box. Does Python play favorites? I think it would have a much larger user base if Windows user got what mac users get. Could someone explain this to me? I don't mean this to start a platform war as I'm really agnostic on the matter. Just curious. Thanks!!!

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Re: selecting a random item from a set
by Alexander Schmolck Dec. 31, 2003

Dec. 31, 2003

"Tim Peters" <tim.one(a)comcast.net> writes: > [Alexander Schmolck] > > Quite a few algortihms prominently feature choosing/removing a single > > random element from a set at a time. > > Really? Feature selection schemes, for example? > > On first sight I can't think of anything better to achieve this with > > `sets.Set` than something along the lines of: > > > > for dummy, randomElement in zip(range(randrange(len(s)+1)), s): pass > > It's too obscure for my tastes, And buggy (a misplaced paren). > but something like that would certainly work. Probably not. I'm not > convinced there's a real need, and given the implementation of sets there's > no way to do it essentially more efficient than the way you've already > figured out > (it can be done using O(1) space instead, s/zip/izip/ s/range/xrange/ ? > but it still takes O(len(s)) time -- the implementation of sets is > lumpy, so the O(1)-time indexing trick used by random.choice() can't apply). The complexity might be the same, but you could certainly do it with a lot less overhead (with C implmented sets, at least). But if really not that many people need it, that's of course not enough of a justification. > If you think this is important enough to be worth the bother <wink>, you > could define a hybrid data structure combining a set and a list, keeping > them in synch. random.choice() can then be applied to the list part to get > a random element in constant time. The only tricky part is deletion of an > element. You need another dict under the covers to map each key to its > index in the list. When it comes time to delete a key, you *overwrite* the > list position it occupied with the last key in the list (and update that > key's index), then reduce the length of the list by 1. That keeps deletion > constant-time (expected-case) too. Yep, such a scheme might be interesting. I currently haven't profiled any of the (unfinished) code yet or thought hard about it, so I don't know the relative importance of large constant factors vs. complexity. I'm not entirely bitten by the premature optimization bug however -- I know that most of the time in an existing implementation of what I want to do in another language is spent doing these set operations and takes minutes to hours to come up with its outputs. 'as

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