🌐 Mailman 3 August 2007 - Python-list - python.org

Re: strange list comprehension on generator
by attn.steven.kuo＠gmail.com Aug. 29, 2007

Aug. 29, 2007

On Aug 29, 6:50 am, Roland Puntaier <Roland.Punta...@br- automation.com> wrote: > def changeOne(aa,idx): > aa[idx]=not aa[idx] > yield aa > for i in range(idx): > for x in changeOne(aa,i): > yield x > > def changeOneOrder(aa): > yield aa > for i in range(len(aa)): > for x in changeOne(aa,i): > yield x > > a=[False]*3 > og=changeOneOrder(a) > #this does not return the way I would expect. why? > list(og) > #returns > #[[False, False, True], [False, False, True], [False, False, True], > [False, False, True], [False, False, True], [False, False, True], [False, > False, True], [False, False, True]] If you want the "intermediate" states of 'a' in list(og), then you need to yield a copy of that list, instead of the list itself: def changeOne(aa, idx): aa[idx] = not aa[idx] yield aa[:] # <------- a copy for i in range(idx): for x in changeOne(aa, i): yield x def changeOneOrder(aa): yield aa[:] # <------- a copy for i in range(len(aa)): for x in changeOne(aa, i): yield x a = [False] * 3 og = changeOneOrder(a) print list(og) Otherwise, as you've already noticed, you can loop over the iterator and do something with the "instantaneous" state of 'a'. -- Hope this helps, Steven

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handling tabular data in python--newbie question
by hyena Aug. 29, 2007

Aug. 29, 2007

Hi, Just jump in python few days. I am wondering how to store and index a table in python effectively and easily.I think the basic data types are not very straight foward to handle a table (eg, from csv or data base.) I have a csv file, the first row of it is column names and the rest rows are data. There are some tens of columns and hundreds rows in the file. I am planning to use the column names as variables to access data, currently I am thinking of using a dictionary to store this file but did not figure out a elegant way to start. Any comments and suggestions are wellcomed. Please forgive me if this question is too naive , and yes, I did search google a while but did not find what I want. Thanks

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Re: strange list comprehension on generator
by "Martin v. Löwis" Aug. 29, 2007

Aug. 29, 2007

> #this does not return the way I would expect. why? You yield the very same list object all the times. So when you make a later change, all earlier results will get changed, too (since they are the same object). Of course, it won't affect the terminal output, so you don't see that the older values changed in the example that you think works as expected. HTH, Martin

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Re: strange list comprehension on generator
by Bjoern Schliessmann Aug. 29, 2007

Aug. 29, 2007

No greeting, no text? Pity. Roland Puntaier wrote: > def changeOne(aa,idx): > aa[idx]=not aa[idx] > yield aa > for i in range(idx): > for x in changeOne(aa,i): > yield x > > def changeOneOrder(aa): > yield aa > for i in range(len(aa)): > for x in changeOne(aa,i): > yield x Okay, two generator definitions. > a=[False]*3 > og=changeOneOrder(a) > #this does not return the way I would expect. why? What do you expect? You created a generator object and bound it to "og". Please always state what you expect and what really happens. Fortune telling is not one of my hobbies (and I think I'm not alone with that). Regards, Björn -- BOFH excuse #284: Electrons on a bender

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non-blocking communication with imaplib
by igorr＠ifi.uio.no Aug. 29, 2007

Aug. 29, 2007

Hi, I was wondering if anyone had a suggestion for the following issue. I would like to talk to an IMAP-server, imaplib being the tool of choice, of course. Unfortunately it may happen that the IMAP-server fails to respond to certain commands, and I would like to be able to detect that within a given time period (on the scale of 5-10 seconds). Initially, I thought about playing with setsockblocking() for the communication socket in the imaplib.IMAP4 object. However, the IMAP4 object uses a file object ("created from" the said socket), and the underlying socket must be blocking according to [1]. Is there another option for detecting when the server fails to reply within a given time slot? Could I perhaps temporarily set the socket to non-blocking mode? Or maybe I am attacking this problem the wrong way altogether? Any hints would be greatly appreciated. TIA, ivr [1] <http://docs.python.org/lib/socket-objects.html#l2h-3693> -- <+Kaptein-Dah> igorr: for få parenteser <+Kaptein-Dah> igorr: parenteser virker som lubrication under iterasjon <+Kaptein-Dah> igorr: velkjent

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strange list comprehension on generator
by Roland Puntaier Aug. 29, 2007

Aug. 29, 2007

def changeOne(aa,idx): aa[idx]=not aa[idx] yield aa for i in range(idx): for x in changeOne(aa,i): yield x def changeOneOrder(aa): yield aa for i in range(len(aa)): for x in changeOne(aa,i): yield x a=[False]*3 og=changeOneOrder(a) #this does not return the way I would expect. why? list(og) #returns #[[False, False, True], [False, False, True], [False, False, True], [False, False, True], [False, False, True], [False, False, True], [False, False, True], [False, False, True]] #this works as expected a=[False]*3 og=changeOneOrder(a) og.next() og.next() ... #this works as expected def ty(): yield 1 yield 2 yield 3 tg=ty() list(tg) cheers, Roland

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Re: Pythonwin Install COM exceptions on Windows Vista Ultimate
by Larry Bates Aug. 29, 2007

Aug. 29, 2007

Sandipan News wrote: > What do I do? Can't do without Python! > Any experience, advice, hope is welcome. > Thanks. > Sandipan > > If you are asking if you can run COM objects created in Python on Windows Vista Ultimate, the answer is yes. I have several. -Larry

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Re: Accessing docstrings at runtime?
by Bruno Desthuilliers Aug. 29, 2007

Aug. 29, 2007

Chris Mellon a écrit : > On 8/29/07, Kenneth Love <klove(a)tax.ok.gov> wrote: > >>How do I print the docstring for a class property? (snip) > You're looking at an instance, not at the class. y.x is going through > the descriptor lookup and is returning the string, so the __doc__ is > the the __doc__ of the string object, as you see. > > If you want to look at the property directly, look it up in the class object: > > C.x.__doc__ Or type(y).x.__doc__ if you don't know the class of y.

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Python molecular viewer
by Andy Cheesman Aug. 29, 2007

Aug. 29, 2007

Dear People, I was wondering if people could recommend a simple molecular viewing package written in python. I'm working in Theoretical chemistry and I'm not after an all-singing dancing molecular rendering package(pymol does that rather well) but a program which reads XYZ files and displays simple structures which can be rotated in 3D Thanks Andy

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Re: Haskell like (c:cs) syntax
by Istvan Albert Aug. 29, 2007

Aug. 29, 2007

On Aug 29, 8:12 am, Ricardo Ar�oz <ricar...(a)gmail.com> wrote: > >> Caution : L[0] and L[1:] are COPIES of the head and tail of the list. > Sorry, should have written RETURN copies instead of ARE copies. L[0] does not return a copy, it does what is says, returns the object stored at index 0. i.

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