🌐 Mailman 3 June 2009 - Python-list - python.org

Re: Safe to import __builtin__ ?
by mrstevegross June 2, 2009

June 2, 2009

> Why do you want to import it? > > Seehttp://docs.python.org/library/__builtin__.html I'm using a weird python environment that overloads a few builtin functions. In order to run them, I need to explicitly invoke "__builtin__.foo()" to make sure I get the real builtin version, not the overloaded one. --Steve

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Creating Mac OS X app
by sh00le June 2, 2009

June 2, 2009

Hi, This is my first post here, hope this is the right group, and sorry for my broken English. So, let's start. I have created small PyQt application Simple Task Timer (http://code.google.com/p/simpletasktimer/). Also I created windows binary distro with py2exe, and Linux packages (.rpm and .deb). I would like to have Mac OS X .app binary distro but I don't have Mac OS, and I can't install Mac OS as guest on Virtual Box. Now, I'm searching for some volunteers with Mac OS who would like to test application on Mac OS, and (if it's possible) to create .app binary for Simple Task Timer. Any help would be appreciated. Tnx for reading.

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Re: [Tutor] Challenge supporting custom deepcopy with inheritance
by Michael H. Goldwasser June 2, 2009

June 2, 2009

Hi Kent, Thanks for your thoughts. For the original example code, you are correct that we could make it work by having B provide the one-arg constructor to match A's constructor signature. But I don't see this as a general solution. Having B.__deepcopy__() make a call to A.__deepcopy__() assumes that A supports __deepcopy__ either direclty or indirectly. This is not guaranteed as __deepcopy__ is not supported all the way back to the object base class. It could be that the author of A has guaranteed that the syntax deepcopy(instanceA) is properly supported, but that could be done by other means without an explicit __deepcopy__ (such as relying on a true deep copy, or using getstate/setstate to affect both pickling and deepcopy). As another basic puzzle, consider a class definition for B where B has a registry list that it doesn't want cloned for the new instance (but it does want pickled when serialized). This would seem to require that B implement its own __deepcopy__. We want to somehow rely on the class definition for A to enact the cloning fo the state defined by A. But without knowing about how A supports the deepcopy semantics, I don't see how to accomplish this goal. class B(A): def __init__(self): self.__registry = [] def register(self, obj): self.__registry.append(obj) def __deepcopy__(self, memo={}): dup = ???? # would like something like A's version of deepcopy(self,memo) # as our starting point but we need an instance of class B # and B.__deepcopy__ masks our ability to rely on the # inherited semantics of deepcopy(self) dup.__registry = [] memo[id(self)] = dup return dup On Sunday May 31, 2009, Kent Johnson wrote: > On Sun, May 31, 2009 at 5:35 PM, Michael H. Goldwasser <goldwamh(a)slu.edu> wrote: > > > > Yesterday, I posted a question to python-list involving custom > > deepcopies in an inheritance hierarchy. I haven't received any > > responses, so I thought I'd cross-post to see if anyone on tutor > > has any thoughts. > > > > To avoid splitting the thread, I'll simply reference the original post at > > http://mail.python.org/pipermail/python-list/2009-May/714866.html > > and ask for responses to be sent there. > > Sorry, splitting the thread for you... > > ISTM that in general B.__deepcopy__() should call A.__deepcopy__() to > do the "A" part of the work. In your example, this won't work because > A.__deepcopy__() assumes that subclasses have a one-argument > constructor. So, I would say that B is not fulfilling the contract > assumed by A. > > What if you give B a one-arg constructor by making the bTag argument > optional? Then I think B.__deepcopy__() can call A.__deepcopy__(), > then do the "B" part of the copy on the result. > > Kent +----------------------------------------------- | Michael Goldwasser | Associate Professor | Dept. Mathematics and Computer Science | Saint Louis University | 220 North Grand Blvd. | St. Louis, MO 63103-2007 | | Office: Ritter Hall 6 | Email: goldwamh(a)slu.edu | URL: http://cs.slu.edu/~goldwasser | Phone: (314) 977-7039 | Fax: (314) 977-1452

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Creating a Google Code project for GSoC
by Eric Pruitt June 2, 2009

June 2, 2009

Hello everyone, I am a student working on GSoC 2009 for PSF. My proposal involves making changes to the subprocess module and subprocess.Popen. I wish to create a Google Code project to host my changes so that I can receive feedback from the community. Some of the code I have incorporated falls under an MIT license. Python's license is not GPL but is GPL compatible. What license should the Google Code project fall under? MIT, GPL or something else? Eric

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pyPgSql there is already a transaction in progres
by someone June 2, 2009

June 2, 2009

Hi, I'm using pyPgSQL for accessing Postgres and do some update and select queries. and getting WARNING: there is already a transaction in progress if I run runUpdate more than once. So, what happens is following: 1. SELECT address FROM address WHERE LOWER(address) = LOWER(%s); -- __existRecord 2. BEGIN;DELETE FROM failed WHERE uquery = %s;COMMIT; -- __delQuery 3. SELECT address FROM address WHERE LOWER(address) = LOWER(%s); -- again __existRecord and here I'm getting the warning. Can anyone explain me please what the problem is? I do select, then delete transaction and then select again which doesn't work Regards, Pet class Bla: def __init__: pass def runUpdate(self, number=5): data = {} data = self.__getUpdateItems(number) for row in data: try: if self.__existRecord(row['q']): self.__delQuery(row['q']) except Exception, e: print "Exception", e def __delQuery(self, name): query = """ BEGIN;DELETE FROM failed WHERE uquery = %s;COMMIT; """ try: self.db.execute(query, name) except Exception, e: print "Exception: ", e return True def __existRecord(self, search): query = """ SELECT address FROM address WHERE LOWER(address) = LOWER (%s); """ try: self.db.execute(query, search) except Exception, e: print "Exception: ", e return self.db.fetchall() def __getUpdateItems(self,number=5): values = [number] query = """ SELECT * FROM failed WHERE id IS NULL ORDER BY up DESC LIMIT %s; """ result = [] try: self.db.execute(query, *values) result = self.db.fetchall() except Exception, e: print "Exception getUpdateItems: ", e return result

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Re: do replacement evenly
by Scott David Daniels June 2, 2009

June 2, 2009

oyster wrote: > I have some strings, and I want to write them into a text files, one > string one line > but there is a requirement: every line has a max length of a certain > number ... <description of re-padding a line> If you are doing this to fill and justify text, I seem to remember a research result stating that filled text (with smooth left and right margins) works well for proportional fonts, but decreases readability for fixed pitch fonts, where ragged right (or ragged left) works better. Sadly, I have no idea where I read that as it is only in the recesses of my somewhat addled brain. --Scott David Daniels Scott.Daniels(a)Acm.Org

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Re: what I would like python.el to do (and maybe it does)
by rustom June 2, 2009

June 2, 2009

> But since i like to do it The Right Way, I would > like to let the python-mode worry about this... > > Sorry if this is just a bunch of obvious thoughts to most of you. > > Regards, > Giovanni I dont see whats the problem. Heres my attempt to show you my emacs windows using python-mode (python.el never worked for me) ## Window 1 file foo.py (python mode) x = 1 y = 2 ## Window 2 python interpreter >>> #### Goto the python file (foo.py) Select the x=1 line C-c | (which is py-execute-region) Goto python interpreter window >>> x 1 >>> y ... NameError: y not defined What more/less/else do you want? Are you using python-mode.el or python.el?

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Re: Challenge supporting custom deepcopy with inheritance
by Scott David Daniels June 2, 2009

June 2, 2009

Michael H. Goldwasser wrote: > On Monday June 1, 2009, Scott David Daniels wrote: > >> Michael H. Goldwasser wrote: >> > .... I'll accept the "small price for flexibility" that you >> > note, if necessary. However, I still desire a cleaner solution. >> >> You seem to think that "deepcopy" is a well-defined concept. .... > > It is clear from my original statement of the question that there is > a need for classes to be able to customize their own semantics for > supporting the deepcopy function. That is why the deepcopy function > looks for a __deepcopy__ method within a class as a hook. > > My concern involves the challenge of providing a valid > implementation for __deepcopy__ at one level of inheritance without > being overly dependent on the internal mechanism used by ancestor > classes in supporting deepcopy. I don't see how your comments > address that question. I only meant to say, if you are looking for something neater, consider whether there is such a thing. Issues with deepcopy may be (and I suspect are) inherently messy. Further, inheritance usually provides (in practice) a "built from" relationship, not an "is a" relationship. "Liskov Substitutability," is a design goal, honored except in corner cases and where inconvenient. --Scott David Daniels Scott.Daniels(a)Acm.Org

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do replacement evenly
by oyster June 2, 2009

June 2, 2009

I have some strings, and I want to write them into a text files, one string one line but there is a requirement: every line has a max length of a certain number(for example, 10), so I have to replace extra SPACE*3 with SPACE*2, at the same time, I want to make the string looks good, so, for "I am123456line123456three"(to show the SPACE clearly, I type it with a number), the first time, I replace the first SPACE, and get "I am23456line123456three", then I must replace at the second SPACE block, so I get "I am23456line23456three", and so on, if no SPACE*3 is found, I have to aString.replace(SPACE*2, SPACE). I hope I have stated my case clear. Then the question is, is there a nice solution? thanx

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Re: do replacement evenly
by Mike Kazantsev June 2, 2009

June 2, 2009

On Tue, 2 Jun 2009 19:10:18 +0800 oyster <lepto.python(a)gmail.com> wrote: > I have some strings, and I want to write them into a text files, one > string one line > but there is a requirement: every line has a max length of a certain > number(for example, 10), so I have to replace extra SPACE*3 with > SPACE*2, at the same time, I want to make the string looks good, so, > for "I am123456line123456three"(to show the SPACE clearly, I type it > with a number), the first time, I replace the first SPACE, and get "I > am23456line123456three", then I must replace at the second SPACE > block, so I get "I am23456line23456three", and so on, if no SPACE*3 > is found, I have to aString.replace(SPACE*2, SPACE). > I hope I have stated my case clear. > > Then the question is, is there a nice solution? Not so nice, but it should be faster than whole lot of string manipulations, especially on longer lines: len_line = 55 line = 'Thats a whole line of some utter nonsense ;)' words = line.split() count_space = len_line - len(''.join(words)) count_span = len(words) - 1 span_min = (count_space // count_span) * ' ' count_span_max = count_space - (count_span * len(span_min)) line = buffer(words[0]) for word in words[1:]: if count_span_max: count_span_max -= 1 line += span_min + ' ' else: line += span_min line += word print '%d chars: %r'%(len(line), line) -- Mike Kazantsev // fraggod.net

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