Re: how to append to a list twice?
Fredrik Lundh [EMAIL PROTECTED] wrote: Alex Martelli wrote: But of course that only does it once, and I don't want to have to copy and paste the append line. Perhaps there's a better way than this. def makeseries(N): series = [N] append = series.append for tailer in xrange(N-1, -1, -1): append(tailer) append(tailer) But Now You've Violated The DRY Principle!!! Just as with any other unrolled loop, yes -- loop unrolling is an optimization which is based exactly on exchanging some textual repetition for a tiny bit more speed. Of course, optimizations can easily be premature, and in any case need to be checked by measurement. E.g., here are a few variations: def makeseries_a(N): series = [N] append = series.append for tailer in xrange(N-1, -1, -1): append(tailer) append(tailer) return series def makeseries_b(N): series = [N] append = series.append for tailer in xrange(N-1, -1, -1): for x in (1,2): append(tailer) return series def makeseries_c(N): series = [N] extend = series.extend for tailer in xrange(N-1, -1, -1): extend((tailer,tailer)) return series def makeseries_d(N): series = [N] extend = series.extend for tailer in xrange(N-1, -1, -1): extend((tailer,)*2) return series And: brain:~/downloads alex$ python -mtimeit -s'import rep' 'rep.makeseries_a(100)' 1 loops, best of 3: 31.7 usec per loop brain:~/downloads alex$ python -mtimeit -s'import rep' 'rep.makeseries_b(100)' 1 loops, best of 3: 57.4 usec per loop brain:~/downloads alex$ python -mtimeit -s'import rep' 'rep.makeseries_c(100)' 1 loops, best of 3: 36.2 usec per loop brain:~/downloads alex$ python -mtimeit -s'import rep' 'rep.makeseries_d(100)' 1 loops, best of 3: 54.4 usec per loop So, it would seem that (at least among these few variations) I had guessed right, this time -- the loop-unrolling is beneficial and append is minutely better than extend. Of course, the yanking from the loopbody of the boundmethod is also a key optimization here -- with unyanked (more natural) versions [[i.e., calling series.append or series.extend right in the loop body]] I measure: brain:~/downloads alex$ python -mtimeit -s'import rep' 'rep.makeseries_a(100)' 1 loops, best of 3: 57.3 usec per loop brain:~/downloads alex$ python -mtimeit -s'import rep' 'rep.makeseries_b(100)' 1 loops, best of 3: 83.5 usec per loop brain:~/downloads alex$ python -mtimeit -s'import rep' 'rep.makeseries_c(100)' 1 loops, best of 3: 48 usec per loop brain:~/downloads alex$ python -mtimeit -s'import rep' 'rep.makeseries_d(100)' 1 loops, best of 3: 68.4 usec per loop Alex -- http://mail.python.org/mailman/listinfo/python-list
Re: Generate a sequence of random numbers that sum up to 1?
Anthony Liu [EMAIL PROTECTED] wrote: ... As a matter of fact, given that we have to specify the number of states for an HMM, I would like to create a specified number of random floating numbers whose sum is 1.0. def forAL(N): N_randoms = [random.random() for x in xrange(N)] total = sum(N_randoms) return [x/total for x in N_randoms] Does this do what you want? Of course, the resulting numbers are not independent, but then the constraints you pose would contradict that. Alex -- http://mail.python.org/mailman/listinfo/python-list
Looking for resources for making the jump from Java to Python easier and more productive
I'm just starting out with python, after having a long history with Java. I was wondering if there were any resources or tips from anyone out there in Python-land that can help me make the transition as successfully as possible? Perhaps you've made the transition yourself or just have experience with folks who have made the transition. I'm looking for the common types of mistakes that say a Java/C# or even C++ developer may commonly make. More examples like those highlighted here http://dirtsimple.org/2004/12/python-is-not-java.html would be particularly useful. I've already made the static class method mistake, and been thoroughly confused by packages and imports/froms and extremely frustrated with attempting to call super constructors etc. I'm getting the hang of passing around functions (ala the command pattern), customising the operators and extending inbuilt classes. All of these concepts I've done before so there nothing really great and wonderful about using them in another language. Some of the really powerful ideas of python (eg as suggested in the link) about creating one function containing a template function that can cater to all possible implementations sounds really cool and alien to me at the same time. That's the sort of stuff I'm interested in. At this point in time I'd say my python code is more coding Java in python than doing it in a pythonic way. Perhaps there some good/great examples of Python scripts or projects that I could look at to get inspired or learn pythonic implementation ideas? I just don't know of any. Are there python specific equivalents to the common Patterns, Anti-Patterns and Refactoring books that are so prevalent as reccomended reading in C++ and Java? If so what? Given the rising popularity of Python these days there has got to be a few of you out there who've made the transition successfully and have some pearls-of-wisdom to share that you'd wished you'd known about earlier. Thanks Todd -- http://mail.python.org/mailman/listinfo/python-list
Re: Can you create an instance of a subclass with an existing instance of the base class?
Sandra-24 wrote: Can you create an instance of a subclass using an existing instance of the base class? Such things would be impossible in some languages or very difficult in others. I wonder if this can be done in python, without copying the base class instance, which in my case is a very expensive object. You can change the class of an instance by assigning to the __class__ attribute. The new class doesn't even need to be a subclass of the old: class A(object): ... def __init__(self, name): ... self.name = name ... def show(self): print self.name ... a = A(alpha) a.show() alpha class B(object): ... def show(self): print self.name.upper() ... a.__class__ = B a.show() ALPHA Peter -- http://mail.python.org/mailman/listinfo/python-list
Re: Generate a sequence of random numbers that sum up to 1?
Anthony Liu wrote: I am at my wit's end. I want to generate a certain number of random numbers. This is easy, I can repeatedly do uniform(0, 1) for example. But, I want the random numbers just generated sum up to 1 . I am not sure how to do this. Any idea? Thanks. -- import random def partition(start=0,stop=1,eps=5): d = stop - start vals = [ start + d * random.random() for _ in range(2*eps) ] vals = [start] + vals + [stop] vals.sort() return vals P = partition() intervals = [ P[i:i+2] for i in range(len(P)-1) ] deltas = [ x[1] - x[0] for x in intervals ] print deltas print sum(deltas) --- Gerard -- http://mail.python.org/mailman/listinfo/python-list
Re: Generate a sequence of random numbers that sum up to 1?
Gerard Flanagan wrote: Anthony Liu wrote: I am at my wit's end. I want to generate a certain number of random numbers. This is easy, I can repeatedly do uniform(0, 1) for example. But, I want the random numbers just generated sum up to 1 . I am not sure how to do this. Any idea? Thanks. -- import random def partition(start=0,stop=1,eps=5): d = stop - start vals = [ start + d * random.random() for _ in range(2*eps) ] vals = [start] + vals + [stop] vals.sort() return vals P = partition() intervals = [ P[i:i+2] for i in range(len(P)-1) ] deltas = [ x[1] - x[0] for x in intervals ] print deltas print sum(deltas) --- def partition(N=5): vals = sorted( random.random() for _ in range(2*N) ) vals = [0] + vals + [1] for j in range(2*N+1): yield vals[j:j+2] deltas = [ x[1]-x[0] for x in partition() ] print deltas print sum(deltas) [0.10271966686994982, 0.13826576491042208, 0.064146913555132801, 0.11906452454467387, 0.10501198456091299, 0.011732423830768779, 0.11785369256442912, 0.065927165520102249, 0.098351305878176198, 0.077786747076205365, 0.099139810689226726] 1.0 -- http://mail.python.org/mailman/listinfo/python-list
Re: ANN: XMLObject
Hello! I tried to use this class in my work. But I Can't understand the next. I have an XML file, where I store an information by this way First_NameWesley/First_Name Last_NameHunter/Last_Name ie. How can I get the value between First_Name and /First_Name? Thanks in advance. aum wrote: Hi folks, I've just released an XML object wrapper called XMLObject, which aims to do for XML file handling what SQLObject does for database access. XMLObject wraps XML files as Python objects, and lets you work with XML data more quickly and easily, and with code that's shorter and much more readable than the raw python XML APIs. It borrows some ideas from 'xml_objectify', but uses none of its code. In addition to 'xml_objectify', it lets you make changes within the document, and to save back to an XML file. http://www.freenet.org.nz/python/xmlobject -- http://mail.python.org/mailman/listinfo/python-list
Re: Pythonesque interface.
Gaz: Right now im trying to dl Jython (SF.net server down?), if it's language sintaxis is just like Python and allows to use numpy and PIL, im in! (i think :) ) I don't think you can do that, but you can create and show images anyway (and maybe read the pointer position too). Sorry for the OP, I have seen lot of people use it here, I'll avoid such things in the future. Bye, bearophile -- http://mail.python.org/mailman/listinfo/python-list
Re: proposed Python logo
In article [EMAIL PROTECTED], Dennis Lee Bieber [EMAIL PROTECTED] wrote: On Fri, 21 Apr 2006 16:13:53 -0700, Carl J. Van Arsdall [EMAIL PROTECTED] declaimed the following in comp.lang.python: Lawrence D'Oliveiro wrote: Six words: copyright violation ... trademark violation. Six? Looks more like 4 to me. Ah, but maybe it is self-referential... At last, someone with the imagination I thought would be more common among Pythonistas. :) -- http://mail.python.org/mailman/listinfo/python-list
Re: Looking for resources for making the jump from Java to Python easier and more productive
In article [EMAIL PROTECTED], ToddLMorgan [EMAIL PROTECTED] wrote: I'm looking for the common types of mistakes that say a Java/C# or even C++ developer may commonly make. Using subclassing when you don't have to. For instance, you might have a Java method which takes an argument of type java.io.OutputStream to which it writes. You might translate this to a Python method to which you are careful to only pass instances of subclasses of file objects. But in fact there is no necessity for this: you are free to pass any object which has appropriate members. I suppose this is an instance of the more general rule: using OO when you don't have to. -- http://mail.python.org/mailman/listinfo/python-list
Re: Looking for resources for making the jump from Java to Python easier and more productive
In article [EMAIL PROTECTED], ToddLMorgan [EMAIL PROTECTED] wrote: Are there python specific equivalents to the common Patterns, Anti-Patterns and Refactoring books that are so prevalent as reccomended reading in C++ and Java? I don't think they exist. Such books are targeted more towards development in a corporate environment, where every proposal has to go through multiple layers of management, and nothing is ever done by individuals working alone, always by teams working on separate parts of the project. And also where the end-users don't really get much say in how things are supposed to work. It's only in such a high-overhead, top-down, cover-your-ass environment that such books are looked on as being at all useful. Possibly on the grounds that nobody ever got fired for buying them. I'd say languages like Python and Perl are the absolute antithesis of this sort of development culture. -- http://mail.python.org/mailman/listinfo/python-list
Re: Raising a specific OSError
In article [EMAIL PROTECTED], David Hirschfield [EMAIL PROTECTED] wrote: When I attempt to perform a file operation on a non-existent file, I get an OSError: [Errno 2], but what if I want to raise one of those myself? raise OSError(2, No such file or directory) -- http://mail.python.org/mailman/listinfo/python-list
Re: another question about buffers
In article [EMAIL PROTECTED], [EMAIL PROTECTED] wrote: databack = sockobj.recv(1028) if databack: print 'caught a message %s bytes ' % len(databack) else: print 'fail to recieve data from server' the output in the terminal runs fine until it fails to get the databack, it prints out the fail to receive from server bit. Perhaps the string you are receiving back on the second recv is being interpreted as False. -- http://mail.python.org/mailman/listinfo/python-list
Re: send cookie on request with urllib2
In article [EMAIL PROTECTED], [EMAIL PROTECTED] (John J. Lee) wrote: No, scolded Yoda. Do, or do not. There is no try. Convincing argument against exceptions, don't you think. :) -- http://mail.python.org/mailman/listinfo/python-list
Re: Define type of 'module' object that is imported
Zachary Pincus wrote: Hi folks, I'm sure this has come up before, but the search terms I've been using are so non-specific that I can't get any traction on Google. Here's my question: I have written a subclass of ModuleType that handles lazy loading of some slow resources. I would like a given module to be created as an instance of that particular subclass on import, so that if I do: import foo type(foo) I get type 'myModule' instead of type 'module'. Is there any way to effect this? Something like __metaclass__ = ... but at the beginning of a module instead of at the beginning of a class? Would be interesting to know about the motivation. Is foo just your own module or any module. * you can replace __import__ * you can set sys.modules['foo']=mymod (in sitecustomize.py ? ) * your module can be a class instance as well in newer pythons (2.2+?); = you can set sys.modules['foo']=Foo() # Foo having properties ... * simply import certain expensive modules only ad-hoc * maybe you don't need it as module at all, but an instance. or you avoid pre-computing things in global namespace. ... robert --- PS: In the Python standard lib there are some slow importing monsters. The worst is now urllib2 needing up to a second to import. Thats because there is a questionable style of importing all kind of expensive stuff that _might_ be useful in advance as if we had C-style compiler #include-s. Yet Python allows best-amongst-most-programming-languages dynamic modularization of code by local/late imports. Most time you'll see, that the imported modules are anyway only needed in very few locations. the pychecker helps. See rejected: http://sourceforge.net/tracker/index.php?func=detailaid=1053150group_id=5470atid=305470 Meanwhile the cookielib is also amongst those urllib2 inhabitants - and its the slowest towards my profile runs. I've regular private patches on my production python installation to get apps (startup) fluid. Maybe that rejected sf request should be re-opened, and a request put to optimize the python lib for late dynamic import's - at least in locations where (regardign a profiler inspection) it pays off well on low coding costs ? -- http://mail.python.org/mailman/listinfo/python-list
Re: FOUNDIT (was Re: massive threading performance)
In article [EMAIL PROTECTED], Paul Sijben [EMAIL PROTECTED] wrote: I found that the problem was caused by the sending thread not giving control back quickly enough to the receiving thread. Also in going through the code I found an old self.s.setblocking(0)call that was no longer relevant. Removing that solved my problem. Something that took 20 seconds now takes just 1. You might also find that it goes still faster if you forego threading and use a select.select loop. -- http://mail.python.org/mailman/listinfo/python-list
Re: Uniquifying a list?
In article [EMAIL PROTECTED], Felipe Almeida Lessa [EMAIL PROTECTED] wrote: list(set(x)) is the clear winner with almost O(1) performance. Moral: in an interpreted language, use builtins as much as possible. -- http://mail.python.org/mailman/listinfo/python-list
Re: [OT] Any Python lullabies?
In article [EMAIL PROTECTED], Ralf Muschall [EMAIL PROTECTED] wrote: Christos Georgiou wrote: ... that I can sing to my newborn son (actually, born yesterday)? ...but the baby probably won't see the difference. Boy, some people do take the born yesterday bit to heart. don't they. :) -- http://mail.python.org/mailman/listinfo/python-list
Re: a flattening operator?
In article [EMAIL PROTECTED], gangesmaster [EMAIL PROTECTED] wrote: as we all know, * (asterisk) can be used to inline or flatten a tuple into an argument list, i.e.: def f(a, b, c): ... x = (1,2,3) f(*x) so... mainly for symmetry's sake, why not make a flattening operator that also works outside the context of function calls? def flatten(*a) : return a -- http://mail.python.org/mailman/listinfo/python-list
Re: Looking for resources for making the jump from Java to Python easier and more productive
ToddLMorgan wrote: I'm just starting out with python, after having a long history with Java. I was wondering if there were any resources or tips from anyone out there in Python-land that can help me make the transition as successfully as possible? Perhaps you've made the transition yourself or just have experience with folks who have made the transition. Some time ago I had to learn a bit of Java in order to be able to write some signed jython browser applets that I could use while working at a highly restricted public library computer. So I guess I was coming from the opposite direction :-) Anyway I wondered why (and how!) very small jython scripts could replace large blocks of java code. Maybe looking at it from a jython perspective will be educational for you. I think it would be a lot of fun realizing how much java code can actually be 'automatically' generated or filled in by jython traversing its class system. Also I'm hoping it would produce an opportunity for an advanced java coder to write some cool signed java applet in jython that would have the look and feel of idle.py for python but that would run from a webbrowser. I know it can be done because I did write some experimental but still already very functional things like a jython console webbrowser applet, a websucker.py running from within a browser, and I hacked some other jython editor-console (eclipse is good for such things) to add some functionality and do my own signing and library selection. Don't ask for my code yet though, it's nowhere near presentable. Anyway, since then I found a job that gives me access to less locked down computers which is also fun. Anton -- http://mail.python.org/mailman/listinfo/python-list
Re: perspective on ruby
Edward Elliott wrote: Alex Martelli wrote: While Mozart appears cool, I really think that a wider variety of languages would help -- some machine code (possibly abstract a la Mixal), C (a must, *SO* much is written in it!), at least one of C++, D, or ObjectiveC, either Scheme or Lisp, either *ML or Haskell, either Python or Ruby, and at least one OOP-only language such as Java, C#, Eiffel, or Smalltalk. Yeah I agree that more is better. The problem is using a new language every couple courses without bogging down in implementation details. Personally I'd just say Here's a book, learn it yourself. It's what they gotta do on the job anyway. Yes - start them explore. I'd not want to be teached a specific _language_ in a course longer that one day. A language cannot be teached. Who of the posters in this thread want themselves to be _teached_ more than one day on a language? I've seen many graduates who know Java, C, this and that words and patterns, but hardly can write a loop and evolve things. Those, who can write loops are mostly self-educated and can do all things quickly in any language. Isn't the fun, finding the right tools for certain purposes one-self? The job of (CS) courses more to provide a map ( what fun to explore yourself ) and display extremes (ASM and Lisp) to prevent from identification ? -robert -- http://mail.python.org/mailman/listinfo/python-list
Re: Uniquifying a list?
There is my version too: http://aspn.activestate.com/ASPN/Cookbook/Python/Recipe/438599 Bye, bearophile -- http://mail.python.org/mailman/listinfo/python-list
Re: how to append to a list twice?
Alex Martelli wrote: But Now You've Violated The DRY Principle!!! Just as with any other unrolled loop, yes -- loop unrolling is an optimization which is based exactly on exchanging some textual repetition for a tiny bit more speed. I had hoped that the Unusual Capitalization would have been enough to make up for the missing smiley... (but note that the OP explicitly didn't want to copy and paste; given that he wrote a newsgroup posting instead seems to indicate that his programming editor isn't quite as good as the editor in his newsreader) /F -- http://mail.python.org/mailman/listinfo/python-list
Re: String To Dict Problem
Michael Spencer wrote:
Alternatively, you could edit visitName to allow 'True' and any other
identifiers you specify e.g. (untested):
allowed = {True: True, False: False}
def visitName(self,node, **kw):
try:
return self.allowed[node.name]
except KeyError:
raise Unsafe_Source_Error(Strings must be quoted,
node.name, node)
Thank you both Michael and Felipe. The solutions work great!
Regards, Clodoaldo
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repr() for Perl?
Sorry to ask a Perl question here, but... Does Perl have something like Python's repr() function? I want to print out a string and have CR print as \r, LF as \n, etc. I looked in the Perl/Python phrasebook: http://wiki.python.org/moin/PerlPhrasebook but saw nothing along those lines. Thx, Skip -- http://mail.python.org/mailman/listinfo/python-list
Re: what has python added to programming languages? (lets be esoteric, shall we ;)
Wildemar Are there any concepts that python has not borrowed, concepts Wildemar that were not even inspired by other languages? I'd say Guido's willingness to borrow heavily from the best ideas present in other languages ranks right up there as one of its key concepts. Skip -- http://mail.python.org/mailman/listinfo/python-list
Re: repr() for Perl?
[EMAIL PROTECTED] writes: Sorry to ask a Perl question here, but... Does Perl have something like Python's repr() function? I want to print out a string and have CR print as \r, LF as \n, etc. I looked in the Perl/Python phrasebook: http://wiki.python.org/moin/PerlPhrasebook but saw nothing along those lines. perldoc Data::Dumper (but my Perl is rusty) John -- http://mail.python.org/mailman/listinfo/python-list
python's thread problem on Linux platform
I found that multi-threaded program(io-centralize ) runs very slowly on linux while the same program runs very quickly on windows.If I change the thread number to one ,the program runs quickly on linux, in fact the speed is quicker than the multi-threaded version . It turns out that python's multi-thread support on linux has some problems.Any comments? -- http://mail.python.org/mailman/listinfo/python-list
Re: repr() for Perl?
Hi skip Sorry to ask a Perl question here, but... Does Perl have something like Python's repr() function? I want to print out a string and have CR print as \r, LF as \n, etc. I looked in the Perl/Python phrasebook: Have a look at this: # cmp_rep.pl --- # #!/usr/bin/perl -w use String::Escape qw(printable); # - - - - the perl way - - - - - $st = str\ting\n; print In Perl:\n, printable($st); # - - - - the python way - - - - use Inline Python = 'PYEND'; st=str\ting\n; print \nIn Python:\n, repr(st) PYEND # --- # Should give almost the same results Regards Mirco -- http://mail.python.org/mailman/listinfo/python-list
howto py2exe/py2app for self updating application
Hi, I'm creating a GUI program with wxPython which will be distributed for Mac and Windows. The audience of the program is not technical at all (eg they've never heard about Python yet ;-), so everything should go automatically. The program should be able to update itself and to update its database (collection of .txt files). These are two separated things and don't happen simultaneously. I thought of the following: - seperate the code which will be updated and zip it to use a zipimport - zip the .txt files These files can then be downloaded (urllib or so) and if the download has completed succesfully, replace their old files. For the updated python code it is necessary to restart the program for the database not. These questions arise: ++ How can I bundle a zipimport file with py2exe/py2app? Let say this is the folder layout of the program: application.py code.zip (contains main.py, ui.py, etc..) * data.zip (contains .txt files) * other files (preferably bundled but not necessary) such as the wxPython libraries and whatever py2app will want to include (* means should be remote updatable/synchronizable) application.py is just a dummy file which calls code.main.main() Should I declare code.zip as a data file or as a python package? Of course it would be nice if someone be so kind to suggest a simple setup.py recipee for this... ++ I have Python2.4, wxPython2.6.3, OS X 10.4 Will it run on other versions of OS X? If not will a version compiled with py2app on OS X 10.3 run on OS X 10.4 or do I need to provide a file for every OS X version? ++ Do I have to declare something special for py2app and wxPython? Thanks in advance, Stani PS Please cc your answer to spe.stani.be IatI gmail.com -- http://mail.python.org/mailman/listinfo/python-list
String formatting using dictionaries
I know how to format strings using a dictionary:
d = {'list':[0, 1]}
'%(list)s' % d
'[0, 1]'
Is it possible to reference an item in the list d['list']?:
'%(list[0])s' % d
Traceback (most recent call last):
File stdin, line 1, in ?
KeyError: 'list[0]'
Regards, Clodoaldo Pinto
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Re: another question about buffers
i think it may be, i am just doing a while 1: loop to just wait for whatever comes in. thanks -- http://mail.python.org/mailman/listinfo/python-list
Re: python's thread problem on Linux platform
[EMAIL PROTECTED] wrote: I found that multi-threaded program(io-centralize ) runs very slowly on linux while the same program runs very quickly on windows.If I change the thread number to one ,the program runs quickly on linux, in fact the speed is quicker than the multi-threaded version . It turns out that python's multi-thread support on linux has some problems.Any comments? Yes. There is a bug in your code. --Irmen -- http://mail.python.org/mailman/listinfo/python-list
Re: String formatting using dictionaries
Clodoaldo Pinto wrote:
I know how to format strings using a dictionary:
d = {'list':[0, 1]}
'%(list)s' % d
'[0, 1]'
Is it possible to reference an item in the list d['list']?:
'%(list[0])s' % d
Traceback (most recent call last):
File stdin, line 1, in ?
KeyError: 'list[0]'
No, but you can provide a modified dictionary to get the effect:
class Dict(dict):
... def __getitem__(self, key):
... if key in self:
... return super(Dict, self).__getitem__(key)
... return eval(key, self)
...
d = Dict(list=[0, 1])
%(list)s % d
'[0, 1]'
%(list[0])s % d
'0'
%(list[1]+42)s % d
'43'
Peter
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Re: a flattening operator?
I think by regular expressions you mean expressions. regular expressions are what you get from import re . mt -- http://mail.python.org/mailman/listinfo/python-list
Re: 有關於 Mining google web services : Building applications with the Google API這本書的範例
[EMAIL PROTECTED] enlightened us with:
?z?n?A
?O?o?A?e???b???s Mining Google Web Services
: Building Applications with
the Google API[EMAIL PROTECTED] 6??Using SQL Server as a
Database??
?M?B?A???q???w?g?w??SQL Server 2000
sp4?A?b?d???{?A.net?X?{?F
?u?L?k?B?z?~???p: System.Data.SqlClient.SqlException: SQL
Server
[EMAIL PROTECTED]@?U?C?P???U??.
Thank you.
It helps if you post in ASCII and English.
Sybren
--
The problem with the world is stupidity. Not saying there should be a
capital punishment for stupidity, but why don't we just take the
safety labels off of everything and let the problem solve itself?
Frank Zappa
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Re: Generate a sequence of random numbers that sum up to 1?
Gerard Flanagan wrote: Gerard Flanagan wrote: Anthony Liu wrote: I am at my wit's end. I want to generate a certain number of random numbers. This is easy, I can repeatedly do uniform(0, 1) for example. But, I want the random numbers just generated sum up to 1 . I am not sure how to do this. Any idea? Thanks. -- import random def partition(start=0,stop=1,eps=5): d = stop - start vals = [ start + d * random.random() for _ in range(2*eps) ] vals = [start] + vals + [stop] vals.sort() return vals P = partition() intervals = [ P[i:i+2] for i in range(len(P)-1) ] deltas = [ x[1] - x[0] for x in intervals ] print deltas print sum(deltas) --- def partition(N=5): vals = sorted( random.random() for _ in range(2*N) ) vals = [0] + vals + [1] for j in range(2*N+1): yield vals[j:j+2] deltas = [ x[1]-x[0] for x in partition() ] print deltas print sum(deltas) finally: --- def distribution(N=2): p = [0] + sorted( random.random() for _ in range(N-1) ) + [1] for j in range(N): yield p[j+1] - p[j] spread = list(distribution(10)) print spread print sum(spread) --- Gerard -- http://mail.python.org/mailman/listinfo/python-list
Re: 有關於 Mining google web services : Building applications with the Google API這本書的範例
I have found the way to solve . So long as alter and establish reading account number and password of the database , finish. Thank you very mush. -- http://mail.python.org/mailman/listinfo/python-list
Re: String formatting using dictionaries
Clodoaldo Pinto wrote:
I know how to format strings using a dictionary:
d = {'list':[0, 1]}
'%(list)s' % d
'[0, 1]'
Is it possible to reference an item in the list d['list']?:
'%(list[0])s' % d
Traceback (most recent call last):
File stdin, line 1, in ?
KeyError: 'list[0]'
not directly, but you can wrap the dictionary in a custom mapper
class:
class mapper(dict):
def __getitem__(self, key):
try:
return dict.__getitem__(self, key)
except KeyError:
k, i = key.split([)
i = int(i[:-1])
return dict.__getitem__(self, k)[i]
d = {list: [0, 1]}
d = mapper(d)
'%(list)s' % d
[0, 1]
'%(list[0])s' % d
0
/F
--
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Jython/Python Programmers
Greetings Group! I'm trying to do a project for my CS class. I'm using this program from Mark Guzdial Jython text: def echoes(snd, delay, factor): sound1 = makeSound(snd) sndlen1 = getLength(sound1) sndlen2 = sndlen1 + (delay * factor) sound2 =decideLen(sound1, sndlen2) # this function return the length # new sound canvas echoamp = 1.0 for echocount in range(1, factor + 1): echoamp = echoamp * 0.6 for echoposition1 in range(1, sndlen1): echoposition2 = echoposition1 + (delay*echocount) value1 = getSampleValueAt(sound1, echoposition1) * echoamp #problem here# value2 = getSampleValueAt(sound2, echoposition2) setSampleValueAt(sound2, echoposition2, value1 + value2) play(sound2) return(sound2) def decideLen(snd1, len1): srate1 = getSamplingRate(snd1) time1 = len1/srate1 time1 =int( ceil(time1)) snd2 = makeEmptySound(time1) return snd2 The problem I'm having is that this program will work for a sampling rate of 22050, but not for the higher quality 44000 rate. I keep getting an array out of bounds message where I marked it on the program. Can't seem to find out why. Too much of a NewBe programmer I guess. Any one help? Regards, Solar^ -- http://mail.python.org/mailman/listinfo/python-list
need a thread to keep a socket connection alive?
hey there, i have a script that waits for message packets from a data server over a socket. it goes a little like this: while 1: x+=1 databack = sockobj.recv(158) if databack: print 'caught a message %s bytes ' % len(databack) if len(databack) 120: message = databack[3:-3] #strip stx and enx print '\n\n%s' % message else: break print 'end data ack' it works fine for a while, but the server requires that i send a heartbeat ping every 600 seconds or it will terminate the connection. so i also need something like while 1: sockobj.send(ping) ping_acknowlage = sockobj.recv(48) time.sleep(550) should i do this with threads? i dont want to interrupt the listening cycle to send a ping. appreciate any tips on how would be the best way to pull this off. -- http://mail.python.org/mailman/listinfo/python-list
Re: howto py2exe/py2app for self updating application
of course! your can be carefully if you do it. but why you ask some here ? in http://www.python.org completly a module for your problem look and try again! [roRoNoaZoro] -- http://mail.python.org/mailman/listinfo/python-list
Re: proposed Python logo
Mike, Excellent artwork! I don't like reinventing the wheel so I propose we reuse someone else's work. I propose something like: http://www.dvdweb.co.uk/reviewgfx/bompfc1.jpg which symbolizes Python's ability to quickly implement many coding ideas or: http://www.phill.co.uk/comedy/python/python15.jpg which symbolizes Python's ability to squash the competition for quick coding or: http://imagecache2.allposters.com/images/CMAG/939-009.jpg which symbolizes Python's place as the pick of the litter. They also symbolize the fact that coder's shouldn't take life too seriously. Happy coding! Mike Michael Tobis wrote: Is this the right room for an argument? http://geosci.uchicago.edu/~tobis/snake.png ok, so my execution is pretty crude, but you can at least see my idea. I trust you to imagine it professionally executed in cheerful colors. Advantages of proposed logo over existing logo SNIP GOOD ARGUMENTS Much as it would be an ego-boost for me to have some version of this idea used for the language, I'm almost as happy with repurposing the most excellent PyCon logo if that is OK with everyone involved. But imo we can't fully promote the power of Python with tadpoles. mt -- http://mail.python.org/mailman/listinfo/python-list
Re: howto py2exe/py2app for self updating application
Can you be more specific? Which module do you mean at python.org? Stani -- http://mail.python.org/mailman/listinfo/python-list
problems when unpacking tuple ...
Dear all, Maybe I stared on the monitor for too long, because I cannot find the bug ... My script transition_filter.py starts with the following lines: import sys for line in sys.stdin : try : for a,b,c,d in line.split() : pass except ValueError , err : print line.split() raise err The output (when given the data I want to parse) is: ['0.0','1','0.04','0'] Traceback (most recent call last): File transition_filter.py, line 10, in ? raise err ValueError: need more than 3 values to unpack What is going wrong here? Why does python think that I want to unpack the outcome of line.split() into three values instead of four? I must be really tired, but I just cannot see the problem. Any clues?? Thanks, - harold - -- http://mail.python.org/mailman/listinfo/python-list
Re: need a thread to keep a socket connection alive?
[EMAIL PROTECTED]: i have a script that waits for message packets from a data server over a socket. Using what network protocol? it works fine for a while, but the server requires that i send a heartbeat ping every 600 seconds or it will terminate the connection. [...] should i do this with threads? i dont want to interrupt the listening cycle to send a ping. If this is a TCP connection with a conversational protocol, you can't have two threads reading bytes of the socket, without some sort of coordination. When one thread parses the bytes it received, some bytes may be part of the next message for the other thread. You may be better off with asynchronous I/O and a state machine model. http://squirl.nightmare.com/medusa/async_sockets.html http://www.python.org/doc/lib/module-asyncore.html http://twistedmatrix.com/projects/core/documentation/howto/clients.html -- René Pijlman -- http://mail.python.org/mailman/listinfo/python-list
Re: problems when unpacking tuple ...
for a,b,c,d in line.split() : [snip] The output (when given the data I want to parse) is: ['0.0','1','0.04','0'] You'll notice that you're not passing any parameters to split(). By default, it splits on whitespace, and your input doesn't have any whitespace in it. Thus, you're actually only getting *one* (not three) elements back. Try using split(,) instead. -tkc -- http://mail.python.org/mailman/listinfo/python-list
Re: problems when unpacking tuple ...
harold: The output (when given the data I want to parse) is: If you'd told us that data, and told us what version of Python you're using, we could have reproduced the problem to look into it. ValueError: need more than 3 values to unpack Why does python think that I want to unpack the outcome of line.split() into three values instead of four? That's not what it says. It says there are only 3 values in the outcome, and it needs more (4 to be precise). -- René Pijlman -- http://mail.python.org/mailman/listinfo/python-list
Re: problems when unpacking tuple ...
harold wrote: Dear all, Maybe I stared on the monitor for too long, because I cannot find the bug ... My script transition_filter.py starts with the following lines: import sys for line in sys.stdin : try : for a,b,c,d in line.split() : pass except ValueError , err : print line.split() raise err The output (when given the data I want to parse) is: ['0.0','1','0.04','0'] Traceback (most recent call last): File transition_filter.py, line 10, in ? raise err ValueError: need more than 3 values to unpack What is going wrong here? Why does python think that I want to unpack the outcome of line.split() into three values instead of four? I must be really tired, but I just cannot see the problem. Any clues?? The 3 values are coming from the first element in the list '0.0' - change it to '0' and you should get: ValueError: need more than 1 value to unpack. See? it's trying to get a,b,c,d from each element of the list not the whole list. Gerard -- http://mail.python.org/mailman/listinfo/python-list
Re: problems when unpacking tuple ...
Rene Pijlman schrieb: harold: The output (when given the data I want to parse) is: If you'd told us that data, and told us what version of Python you're using, we could have reproduced the problem to look into it. Thank you for the answers and sorry that I did not provide more information in the first place. My data file is white space seperated data (space seperated data to be precise) and I am using python 2.4.2 As can be seen, the output of the print statement in the lines except ValueError , err: print line.split() raise err has exactly four values... ValueError: need more than 3 values to unpack Why does python think that I want to unpack the outcome of line.split() into three values instead of four? That's not what it says. It says there are only 3 values in the outcome, and it needs more (4 to be precise). A similar error happens in an interpreter session, when typing for line in [1 2 3 4] : ...for a,b,c,d in line.split() : ...pass ... Traceback (most recent call last): File stdin, line 2, in ? ValueError: need more than 1 value tyo unpack maybe this might help to track down the error. Thanks! - harold - -- http://mail.python.org/mailman/listinfo/python-list
Re: problems when unpacking tuple ...
Thank you Gerard. This must be the problem. Now I can get it working. -- http://mail.python.org/mailman/listinfo/python-list
Re: proposed Python logo
Michael Yanowitz wrote: How about having something from Monty Python in the logo rather than something snakelike. Python was named after Monty Python and not the snake. Snakes also don't appear friendly to me. I think the new logo, while professionally done (bravo!) is unmemmorable. And why such fat snakes? Snakes are not generally thought of as friendly (whereas Pythoin the langauge is); they are not even warm-blooded, and I've always thought the snake a misfit for the language... though the old snake was at least cute. I think something along the flying sheep motif would be memorable - after all, many of us remember it from MP. And something like that much better represents the change in thinking most programmers must undergo to embrace the language. Help, I'm falling --- I can't find any braces! To some extent Python is something completely different. EP calling it Python and then having a flying sheep as a logo - the apparent contradiction might be a good mental reset for those approaching the language. just my two cents -- http://mail.python.org/mailman/listinfo/python-list
Re: String formatting using dictionaries
Thank you guys, you are great! -- http://mail.python.org/mailman/listinfo/python-list
Re: problems when unpacking tuple ...
Em Sáb, 2006-04-22 às 09:21 -0700, harold escreveu: for line in sys.stdin : try : for a,b,c,d in line.split() : pass except ValueError , err : print line.split() raise err Try this: for a, b, c, d in sys.stdin: print a, b, c, d -- Felipe. -- http://mail.python.org/mailman/listinfo/python-list
Re: problems when unpacking tuple ...
harold: A similar error happens in an interpreter session, when typing for line in [1 2 3 4] : ...for a,b,c,d in line.split() : ...pass ... Traceback (most recent call last): File stdin, line 2, in ? ValueError: need more than 1 value tyo unpack maybe this might help to track down the error. Suppose the code was: for x in line.split(): line.split() yields one list with 4 items. The loop will be performed 4 times, assigning one value of the list to x with every iteration. In your code, x is a tuple with 4 elements: a,b,c,d. So with every iteration one value is assigned to that tuple. Since the value is not a sequence of 4 items, this fails. There's two sensible things you can do: for line in [1 2 3 4]: a,b,c,d = line.split() for line in [1 2 3 4]: for a in line.split(): -- René Pijlman -- http://mail.python.org/mailman/listinfo/python-list
Re: Define type of 'module' object that is imported
I would like a given module to be created as an instance of that particular subclass on import, so that if I do: import foo type(foo) I get type 'myModule' instead of type 'module'. Is there any way to effect this? Something like __metaclass__ = ... but at the beginning of a module instead of at the beginning of a class? Would be interesting to know about the motivation. Is foo just your own module or any module. No, just one particular module that needs to do some slow things. I'd like for a user to just be able to type import foo and have the foo module's type be some special type. None of the options below really allow this to happen with one step. It would be more like import lazyFoo; import foo. What I'm doing now is in 'foo.py' performing surgery a la: sys.modules[__name__] = MyModuleClass(...) but that's ugly, and can break the reload mechanism, and causes some other troubles. I would like to do: sys.modules[__name__].__class__ = MyModuleClass but that fails because the module is not a heap type or something. I have also tried: sys.modules[__name__].__getattribute__ = MethodType(myGetattr, sys.modules[__name__], ModuleType) but the custom __getattribute__ never gets called. Hmm, oh well. Zach * you can replace __import__ * you can set sys.modules['foo']=mymod (in sitecustomize.py ? ) * your module can be a class instance as well in newer pythons (2.2 +?); = you can set sys.modules['foo']=Foo() # Foo having properties ... * simply import certain expensive modules only ad-hoc * maybe you don't need it as module at all, but an instance. or you avoid pre-computing things in global namespace. ... -- http://mail.python.org/mailman/listinfo/python-list
Re: problems when unpacking tuple ...
Em Sáb, 2006-04-22 às 14:25 -0300, Felipe Almeida Lessa escreveu: Em Sáb, 2006-04-22 às 09:21 -0700, harold escreveu: for line in sys.stdin : try : for a,b,c,d in line.split() : pass except ValueError , err : print line.split() raise err Try this: for a, b, c, d in sys.stdin: print a, b, c, d Forget that. It was stupid. You should try this instead: for line in sys.stdin: a, b, c, d = line.split() -- Felipe. -- http://mail.python.org/mailman/listinfo/python-list
Re: problems when unpacking tuple ...
harold wrote: Thank you Gerard. This must be the problem. Now I can get it working. Good! I got confused thinking about it too, but I think you just had one loop too many. for line in sys.stdin : try : a,b,c,d = line.split() not: for line in sys.stdin : try : for a,b,c,d in line.split() : pass Gerard -- http://mail.python.org/mailman/listinfo/python-list
Re: send cookie on request with urllib2
Thanks! -- http://mail.python.org/mailman/listinfo/python-list
Re: perspective on ruby
robert wrote: Yes - start them explore. I'd not want to be teached a specific _language_ in a course longer that one day. A language cannot be teached. Who of the posters in this thread want themselves to be _teached_ more than one day on a language? Isn't the fun, finding the right tools for certain purposes one-self? That holds for bright, motivated students. The problem is the others. Some people are totally lost when you throw them a book and say learn this. So the choices are: 1. Do it and watch the rank-and-file students abandon the major 2. Provide more language-specific instruction Now places like Berkeley and MIT can afford to take route 1. They already have a surplus of bright, motivated students. But at many (most?) schools, route 2 is in the dept's best interest. Number of majors affects prestige, influence, and at many state schools funding. Telling the rank-and-file to shove off is shooting themselves in the foot, and ultimately hurts the good students as well with a lesser dept. These depts are walking a tightrope as they try hard to maintain minimum standards. It's not a binary choice really, it's a spectrum. So while route 1 may be better for the profession as a whole, the current educational system has some pretty strong pressures for route 2. -- http://mail.python.org/mailman/listinfo/python-list
Problem calling math.cos()
I have the following module: --- import math def ac_add_a_ph( amp1, ph1, amp2, ph2 ): amp3 = 0.0 ph3 = 0.0 ac1 = ( 0, 0j ) ac2 = ( 0, 0j ) ac3 = ( 0, 0j ) ac1 = complex( amp1 * math.cos( math.radians( ph1 ) ), amp1 * math.sin( math.radians( ph1 ) ) ) ac2 = complex( amp2 * math.cos( math.radians( ph2 ) ), amp2 * math.sin( math.radians( ph2 ) ) ) ac3 = ac1 + ac2 amp3 = math.abs( ac3 ) ph3 = math.atan( ac3.imag / ac3.real ) return [amp3, ph3] -- when I import it (electronics) in python.exe in windows2000 and try to use it, it croaks. ??? import math import electronics print electronics.ac_add_a_ph( 10, 0 , 6 , 45 ) Traceback (most recent call last): File stdin, line 1, in ? File f:\devel\python\electronics.py, line 10, in ac_add_a_ph ac1 = complex( amp1 * math.cos( math.radians( ph1 ) ), amp1 * math.sin( math .radians( ph1 ) ) ) NameError: global name 'cos' is not defined global?? huh? what does abs stand for? why is that not absolute value? hmmm. Hmm, complex numbers, cool I don't even have any idea where C stands on this. -- http://mail.python.org/mailman/listinfo/python-list
Re: repr() for Perl?
Does Perl have something like Python's repr() function? John perldoc Data::Dumper Thanks. Just what the doctor ordered (after setting Useqq). Skip -- http://mail.python.org/mailman/listinfo/python-list
Re: repr() for Perl?
Does Perl have something like Python's repr() function? Mirco Have a look at this: ... Thanks, I'm getting set up to try it just for the exercise. I went with John Lee's Data::Dumper suggestion simply because I already had it installed and have neither String::Escape nor Inline::Python installed. Skip -- http://mail.python.org/mailman/listinfo/python-list
Re: Problem calling math.cos()
In article [EMAIL PROTECTED], Sambo [EMAIL PROTECTED] wrote: I have the following module: --- import math def ac_add_a_ph( amp1, ph1, amp2, ph2 ): amp3 = 0.0 ph3 = 0.0 ac1 = ( 0, 0j ) ac2 = ( 0, 0j ) ac3 = ( 0, 0j ) ac1 = complex( amp1 * math.cos( math.radians( ph1 ) ), amp1 * math.sin( math.radians( ph1 ) ) ) ac2 = complex( amp2 * math.cos( math.radians( ph2 ) ), amp2 * math.sin( math.radians( ph2 ) ) ) ac3 = ac1 + ac2 amp3 = math.abs( ac3 ) ph3 = math.atan( ac3.imag / ac3.real ) return [amp3, ph3] -- when I import it (electronics) in python.exe in windows2000 and try to use it, it croaks. ??? import math import electronics print electronics.ac_add_a_ph( 10, 0 , 6 , 45 ) Traceback (most recent call last): File stdin, line 1, in ? File f:\devel\python\electronics.py, line 10, in ac_add_a_ph ac1 = complex( amp1 * math.cos( math.radians( ph1 ) ), amp1 * math.sin( math .radians( ph1 ) ) ) NameError: global name 'cos' is not defined That's not what I get when I run it (admittedly, not on windows). I get: import math import electronics print electronics.ac_add_a_ph( 10, 0 , 6 , 45 ) Traceback (most recent call last): File stdin, line 1, in ? File electronics.py, line 13, in ac_add_a_ph amp3 = math.abs( ac3 ) AttributeError: 'module' object has no attribute 'abs' which is exactly what I expected, since abs (which is indeed absolute value) is a built-in function, not a part of the math module. Are you sure the stack trace you posted matches the source code you posted? By the way, when using math functions, I find it's usually easier to import them into my namespace by doing from math import *, then I can just use sin(), cos(), etc directly, instead of having to do math.sin() or math.cos(). Especially for common math functions, this makes your code a lot easier to read. -- http://mail.python.org/mailman/listinfo/python-list
Re: Problem calling math.cos()
Sambo [EMAIL PROTECTED] wrote: I have the following module: --- import math def ac_add_a_ph( amp1, ph1, amp2, ph2 ): amp3 = 0.0 ph3 = 0.0 ac1 = ( 0, 0j ) ac2 = ( 0, 0j ) ac3 = ( 0, 0j ) You're defining ac1, ac2, ac3 as tuples, each with two items. That's silly: remove these three useless and confusing lines (the first two are prety silly too). No damage, but, avoidable extra confusion. ac1 = complex( amp1 * math.cos( math.radians( ph1 ) ), amp1 * \ math.sin( math.radians( ph1 ) ) ) ac2 = complex( amp2 * math.cos( math.radians( ph2 ) ), amp2 * \ math.sin( math.radians( ph2 ) ) ) ac3 = ac1 + ac2 amp3 = math.abs( ac3 ) ph3 = math.atan( ac3.imag / ac3.real ) return [amp3, ph3] -- when I import it (electronics) in python.exe in windows2000 and try to use it, it croaks. ??? import math import electronics print electronics.ac_add_a_ph( 10, 0 , 6 , 45 ) Traceback (most recent call last): File stdin, line 1, in ? File f:\devel\python\electronics.py, line 10, in ac_add_a_ph ac1 = complex( amp1 * math.cos( math.radians( ph1 ) ), amp1 * \ math.sin( math .radians( ph1 ) ) ) [[some lines split to respect NNTP's constraint on 80-char lines]] NameError: global name 'cos' is not defined global?? huh? Weird -- I can't reproduce this; it's the kind of symptom you get when mistakenly using a comma instead of a dot, for example, but I don't see that error in your code. What I _do_ see is an AttributeError: 'module' object has no attribute 'abs' on the amp3 assignment -- of course, because that's indeed the fact (abs is a builtin, not a member to module math). Most likely, you got a bit confused and didn't copy-and-paste exactly what was going on. what does abs stand for? why is that not absolute value? hmmm. abs does stand for absolute-value. Hmm, complex numbers, cool I don't even have any idea where C stands on this. C has no stand on complex numbers. Alex -- http://mail.python.org/mailman/listinfo/python-list
Re: Problem calling math.cos()
Sambo wrote: I have the following module: --- import math def ac_add_a_ph( amp1, ph1, amp2, ph2 ): amp3 = 0.0 ph3 = 0.0 ac1 = ( 0, 0j ) ac2 = ( 0, 0j ) ac3 = ( 0, 0j ) ac1 = complex( amp1 * math.cos( math.radians( ph1 ) ), amp1 * math.sin( math.radians( ph1 ) ) ) ac2 = complex( amp2 * math.cos( math.radians( ph2 ) ), amp2 * math.sin( math.radians( ph2 ) ) ) ac3 = ac1 + ac2 amp3 = math.abs( ac3 ) ph3 = math.atan( ac3.imag / ac3.real ) return [amp3, ph3] -- when I import it (electronics) in python.exe in windows2000 and try to use it, it croaks. ??? import math import electronics print electronics.ac_add_a_ph( 10, 0 , 6 , 45 ) Traceback (most recent call last): File stdin, line 1, in ? File f:\devel\python\electronics.py, line 10, in ac_add_a_ph ac1 = complex( amp1 * math.cos( math.radians( ph1 ) ), amp1 * math.sin( math .radians( ph1 ) ) ) NameError: global name 'cos' is not defined global?? huh? That's not what I get. [~]$ cat electronics.py import math def ac_add_a_ph( amp1, ph1, amp2, ph2 ): amp3 = 0.0 ph3 = 0.0 ac1 = ( 0, 0j ) ac2 = ( 0, 0j ) ac3 = ( 0, 0j ) ac1 = complex( amp1 * math.cos( math.radians( ph1 ) ), amp1 * math.sin( math.radians( ph1 ) ) ) ac2 = complex( amp2 * math.cos( math.radians( ph2 ) ), amp2 * math.sin( math.radians( ph2 ) ) ) ac3 = ac1 + ac2 amp3 = math.abs( ac3 ) ph3 = math.atan( ac3.imag / ac3.real ) [~]$ python Python 2.4.1 (#2, Mar 31 2005, 00:05:10) [GCC 3.3 20030304 (Apple Computer, Inc. build 1666)] on darwin Type help, copyright, credits or license for more information. import electronics electronics.ac_add_a_ph(10, 0, 6, 45) Traceback (most recent call last): File stdin, line 1, in ? File electronics.py, line 13, in ac_add_a_ph amp3 = math.abs( ac3 ) AttributeError: 'module' object has no attribute 'abs' what does abs stand for? why is that not absolute value? hmmm. Hmm, complex numbers, cool I don't even have any idea where C stands on this. Change math.abs() to abs(). It's a builtin function. Yes, it does compute the absolute value. Fixing that: import electronics electronics.ac_add_a_ph(10, 0, 6, 45) [14.861117513241918, 0.2895134725436232] -- Robert Kern [EMAIL PROTECTED] I have come to believe that the whole world is an enigma, a harmless enigma that is made terrible by our own mad attempt to interpret it as though it had an underlying truth. -- Umberto Eco -- http://mail.python.org/mailman/listinfo/python-list
Re: Looking for resources for making the jump from Java to Python easier and more productive
http://dirtsimple.org/2004/12/python-is-not-java.html http://dirtsimple.org/2004/12/java-is-not-python-either.html http://dirtsimple.org/2004/12/python-interfaces-are-not-java.html This link seems to be down at the moment. http://naeblis.cx/rtomayko/2004/12/15/the-static-method-thing The above articles were really helped me understand the python way of doining things. In particular they mention language features that may be named the same and do similar things, but would be used for totally different reasons in the two languages. I hope you find them as helpful as I did. -Chris On Sat, Apr 22, 2006 at 12:40:51AM -0700, ToddLMorgan wrote: I'm just starting out with python, after having a long history with Java. I was wondering if there were any resources or tips from anyone out there in Python-land that can help me make the transition as successfully as possible? Perhaps you've made the transition yourself or just have experience with folks who have made the transition. I'm looking for the common types of mistakes that say a Java/C# or even C++ developer may commonly make. More examples like those highlighted here http://dirtsimple.org/2004/12/python-is-not-java.html would be particularly useful. I've already made the static class method mistake, and been thoroughly confused by packages and imports/froms and extremely frustrated with attempting to call super constructors etc. I'm getting the hang of passing around functions (ala the command pattern), customising the operators and extending inbuilt classes. All of these concepts I've done before so there nothing really great and wonderful about using them in another language. Some of the really powerful ideas of python (eg as suggested in the link) about creating one function containing a template function that can cater to all possible implementations sounds really cool and alien to me at the same time. That's the sort of stuff I'm interested in. At this point in time I'd say my python code is more coding Java in python than doing it in a pythonic way. Perhaps there some good/great examples of Python scripts or projects that I could look at to get inspired or learn pythonic implementation ideas? I just don't know of any. Are there python specific equivalents to the common Patterns, Anti-Patterns and Refactoring books that are so prevalent as reccomended reading in C++ and Java? If so what? Given the rising popularity of Python these days there has got to be a few of you out there who've made the transition successfully and have some pearls-of-wisdom to share that you'd wished you'd known about earlier. Thanks Todd -- http://mail.python.org/mailman/listinfo/python-list -- http://mail.python.org/mailman/listinfo/python-list
Re: Problem calling math.cos()
Em Sáb, 2006-04-22 às 15:14 -0400, Sambo escreveu: when I import it (electronics) in python.exe in windows2000 and try to use it, it croaks. ??? $ python2.4 Python 2.4.3 (#2, Mar 30 2006, 21:52:26) [GCC 4.0.3 (Debian 4.0.3-1)] on linux2 Type help, copyright, credits or license for more information. import math def ac_add_a_ph( amp1, ph1, amp2, ph2 ): ... amp3 = 0.0 ... ph3 = 0.0 ... ac1 = ( 0, 0j ) ... ac2 = ( 0, 0j ) ... ac3 = ( 0, 0j ) ... ac1 = complex( amp1 * math.cos( math.radians( ph1 ) ), amp1 * math.sin( math.radians( ph1 ) ) ) ... ac2 = complex( amp2 * math.cos( math.radians( ph2 ) ), amp2 * math.sin( math.radians( ph2 ) ) ) ... ac3 = ac1 + ac2 ... amp3 = math.abs( ac3 ) ... ph3 = math.atan( ac3.imag / ac3.real ) ... return [amp3, ph3] ... ac_add_a_ph(10, 0, 6, 45) Traceback (most recent call last): File stdin, line 1, in ? File stdin, line 10, in ac_add_a_ph AttributeError: 'module' object has no attribute 'abs' abs built-in function abs def ac_add_a_ph(amp1, ph1, amp2, ph2): ... ac1 = complex(amp1 * math.cos(math.radians(ph1)), amp1 * math.sin(math.radians(ph1))) ... ac2 = complex(amp2 * math.cos(math.radians(ph2)), amp2 * math.sin(math.radians(ph2))) ... ac3 = ac1 + ac2 ... ph3 = math.atan(ac3.imag / ac3.real) ... return [abs(amp3), ph3] ... ac_add_a_ph(10, 0, 6, 45) [14.86111751324192, 0.28951347254362308] So: --- import math def polar(rho, theta, theta_in_radians=False) Creates a complex number from its polar form. # Avoid repeating yourself by creating different functions if not theta_in_radians: theta = math.radians(theta) return complex(rho * math.cos(theta), rho * math.sin(theta)) def ac_add_a_ph(amp1, ph1, amp2, ph2): Add two complexes together from their polar form. # You don't have to initialize the variables with 0.0 and such. ac3 = polar(amp1, ph1) + polar(amp2, ph2) ph3 = math.atan(ac3.imag / ac3.real) return (abs(ac3), ph3) # Use a tuple in this case -- *But*, I encourage you using the complex numbers themselves instead of converting to and from over and over. HTH, -- Felipe. -- http://mail.python.org/mailman/listinfo/python-list
Re: Can you create an instance of a subclass with an existing instance of the base class?
Now that is a clever little trick. I never would have guessed you can assign to __class__, Python always surprises me in it's sheer flexibility. In this case it doesn't work. TypeError: __class__ assignment: only for heap types I suspect that's because this object begins its life in C code. The technique of using the __class__.__subclasses__ also fails: TypeError: cannot create 'B' instances This seems more complex than I thought. Can one do this for an object that beings it's life in C? Thanks, -Sandra Peter Otten wrote: Sandra-24 wrote: Can you create an instance of a subclass using an existing instance of the base class? Such things would be impossible in some languages or very difficult in others. I wonder if this can be done in python, without copying the base class instance, which in my case is a very expensive object. You can change the class of an instance by assigning to the __class__ attribute. The new class doesn't even need to be a subclass of the old: class A(object): ... def __init__(self, name): ... self.name = name ... def show(self): print self.name ... a = A(alpha) a.show() alpha class B(object): ... def show(self): print self.name.upper() ... a.__class__ = B a.show() ALPHA Peter -- http://mail.python.org/mailman/listinfo/python-list
Re: Generate a sequence of random numbers that sum up to 1?
Thanks a lot, Alex and Gerard. I am actually not very concerned about the inter-dependency of the floating numbers generated randomly. They are good enough if they are subject to the constraint of summing up to 1. It is simply not worth the time to get an HMM by training it on a large corpus. My sole purpose is to test the predicting power of an HMM, given a set of parameter values. I will definitely try out your snippet and see if it works. Thanks a lot! --- Alex Martelli [EMAIL PROTECTED] wrote: Anthony Liu [EMAIL PROTECTED] wrote: ... As a matter of fact, given that we have to specify the number of states for an HMM, I would like to create a specified number of random floating numbers whose sum is 1.0. def forAL(N): N_randoms = [random.random() for x in xrange(N)] total = sum(N_randoms) return [x/total for x in N_randoms] Does this do what you want? Of course, the resulting numbers are not independent, but then the constraints you pose would contradict that. Alex -- http://mail.python.org/mailman/listinfo/python-list __ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com -- http://mail.python.org/mailman/listinfo/python-list
Re: Problem calling math.cos()
[Robert Kern] ... ph3 = math.atan( ac3.imag / ac3.real ) ... Don't do that: atan2 is the correct way to compute the angle, because the signs of both inputs are needed to determine the correct quadrant. So do: ph3 = math.atan2(ac3.imag, ac3.real) instead. -- http://mail.python.org/mailman/listinfo/python-list
Re: quick surface plots
Did you try mplot3D ? http://www.scipy.org/Wiki/Cookbook/Matplotlib/mplot3D -- N -- http://mail.python.org/mailman/listinfo/python-list
list example
Hi, I wrote this small example to illustrate the usage of lists: even=[] odd=[] for i in range(1,10): if i%2: odd.append(i) else: even.append(i) print odd: +str(odd) print even: +str(even) numbers=even numbers.extend(odd) print numbers:+str(numbers) numbers.sort() print sorted numbers:+str(numbers) any comment, suggestion? Is there something not elegant? Thnx PAolo -- http://mail.python.org/mailman/listinfo/python-list
Re: list example
No substantive problems. The str() calls are unnecessary, print calls list.__str__ already. You can replace the loop with list comprehensions or slices. Same result, a bit more succinct. See these pages for more: http://docs.python.org/lib/typesseq.html http://docs.python.org/tut/node7.html (section 5.1.4) PAolo wrote: Hi, I wrote this small example to illustrate the usage of lists: even=[] odd=[] for i in range(1,10): if i%2: odd.append(i) else: even.append(i) print odd: +str(odd) print even: +str(even) numbers=even numbers.extend(odd) print numbers:+str(numbers) numbers.sort() print sorted numbers:+str(numbers) any comment, suggestion? Is there something not elegant? Thnx PAolo -- http://mail.python.org/mailman/listinfo/python-list
Python on WinXP: 7 Minutes To Hello World!
I started a long email to a friend about how to get up and running on Python, then I thought, why not make something I can post? It's NOT a tutorial. Just a specific, narrow, quick installation guide for Windows XP users. Would love comments, but probably can't incorporate them until Monday, because I have a long drive ahead of me. Thanks for any help. http://www.dooling.com/index.php/category/geekophilia rpd -- http://mail.python.org/mailman/listinfo/python-list
Re: Problem calling math.cos()
In article [EMAIL PROTECTED], Tim Peters [EMAIL PROTECTED] wrote: [Robert Kern] ... ph3 = math.atan( ac3.imag / ac3.real ) ... Don't do that: atan2 is the correct way to compute the angle, because the signs of both inputs are needed to determine the correct quadrant. So do: ph3 = math.atan2(ac3.imag, ac3.real) instead. I certainly agree about using atan2() instead of atan(), but I'm surprised there's not an easier way to get the phase of a complex, just like abs() gives you the modulus. I can see why you wouldn't want to pollute the global namespace with another built-in just for this purpose, but surely a complex.phase property wouldn't hurt? -- http://mail.python.org/mailman/listinfo/python-list
Re: list example
PAolo wrote: any comment, suggestion? Is there something not elegant? Try this: even = range(10)[0::2] odd = range(10)[1::2] -- http://mail.python.org/mailman/listinfo/python-list
Re: Lamdba forms
Ant wrote: Fair enough. I've just found this as well, which implies that lambda isn't being killed off in 3.0: http://www.python.org/dev/peps/pep-3100/ In particular: Lambdas will have to be parenthesized [23] Also: http://www.python.org/doc/essays/ppt/accu2006/Py3kACCU.ppt slide 14. -- http://mail.python.org/mailman/listinfo/python-list
Re: Problem calling math.cos()
[Roy Smith] I certainly agree about using atan2() instead of atan(), but I'm surprised there's not an easier way to get the phase of a complex, just like abs() gives you the modulus. I can see why you wouldn't want to pollute the global namespace with another built-in just for this purpose, but surely a complex.phase property wouldn't hurt? Or method. Does anyone care enough to do the work? is the real question. I don't :-) -- http://mail.python.org/mailman/listinfo/python-list
check whether a value is scalar
Hi, I want to check whether a value is a scalar. A scalar can be: - None (null) - string - number (integer, float) - boolean How can I validate a value is one of these types? I care about the value only, and not its class methods. An object is not a scalar, since it's not a simple value. An array might be considered as scalar. The issue is I want to keep a set of values to share among several applications in different languages, and only scalar values can be shared. Since objects are not the same in all languages, it's possible to share only simple values. -thanks -- http://mail.python.org/mailman/listinfo/python-list
Re: Can my python script return a value to the c program executing it?
Like this ? http://aspn.activestate.com/ASPN/Mail/Message/python-list/1304518 Philippe vduber6er wrote: I have a C program that calls my python script by exec_pycode(code); code = import CheckFasta\nCheckFasta.CheckFasta (\sampledata.txt\, %d)\n, PyNum); CheckFasta.py is my python script with a def CheckFasta in it that returns a string. Is there a way for my C code to get the return value from CheckFasta? Example: If CheckFasta returns hello world can I somehow do something like returnstring = exec_pycode(code); where returnstring will contain hello world after the line above? Thanks -- http://mail.python.org/mailman/listinfo/python-list
Re: list example
PAoloany comment, suggestion? Is there something not elegant? Here you can see many little differences, some of them reflect just my style, but some other of them are Python standard style guidelines: even = [] odd = [] for i in xrange(1, 10): if i % 2: odd.append(i) else: even.append(i) print Odd:, odd print Even:, even numbers = even + odd print Numbers:, numbers numbers.sort() print Sorted numbers:, numbers There are surely more compact versions of that, but compactness is usually less important than clarity, expecially for someone that is learning Python. This is a more compact version (with the suggestion by Wojciech Mula, modified in two ways): even = range(1, 10)[1::2] odd = range(1, 10)[0::2] print Odd:, odd print Even:, even numbers = even + odd print Numbers:, numbers print Sorted numbers:, sorted(numbers) Bye, bearophile -- http://mail.python.org/mailman/listinfo/python-list
Re: problems when unpacking tuple ...
Thanks for all your answer! Of course, I wanted to assign the outcome of the split(), not to iterate over them. Thinks are done so easy in python that, sometimes, one does not even notice that one actually does them ;-) Cheers, - harold - -- http://mail.python.org/mailman/listinfo/python-list
Re: check whether a value is scalar
In article [EMAIL PROTECTED], Eli [EMAIL PROTECTED] wrote: Hi, I want to check whether a value is a scalar. A scalar can be: - None (null) - string - number (integer, float) - boolean How can I validate a value is one of these types? I care about the value only, and not its class methods. An object is not a scalar, since it's not a simple value. An array might be considered as scalar. The issue is I want to keep a set of values to share among several applications in different languages, and only scalar values can be shared. Since objects are not the same in all languages, it's possible to share only simple values. -thanks I'm not sure what scalar means in this context. You say an object is not a scalar, but you also assert that an integer is a scalar. These are contradictory statements, since integers *are* objects: isinstance (1, object) True You say that numbers are scalars. All nunmbers, or just integers and floats? What about complex numbers? What about long integers? In any case, the way to check for a type is with isinstance(), as I did above). -- http://mail.python.org/mailman/listinfo/python-list
Re: check whether a value is scalar
would isinstance(value,(type(None),str,int,float,bool)) be enough? This yields true if the type value is in the list of type objects given as second argument, or a subtype of one of them. What, however, do you mean with I care about the value only, and not its class method? -- http://mail.python.org/mailman/listinfo/python-list
Re: Problem calling math.cos()
Roy Smith wrote: In article [EMAIL PROTECTED], Sambo [EMAIL PROTECTED] wrote: I have the following module: --- import math def ac_add_a_ph( amp1, ph1, amp2, ph2 ): amp3 = 0.0 ph3 = 0.0 ac1 = ( 0, 0j ) ac2 = ( 0, 0j ) ac3 = ( 0, 0j ) ac1 = complex( amp1 * math.cos( math.radians( ph1 ) ), amp1 * math.sin( math.radians( ph1 ) ) ) ac2 = complex( amp2 * math.cos( math.radians( ph2 ) ), amp2 * math.sin( math.radians( ph2 ) ) ) ac3 = ac1 + ac2 amp3 = math.abs( ac3 ) ph3 = math.atan( ac3.imag / ac3.real ) return [amp3, ph3] -- when I import it (electronics) in python.exe in windows2000 and try to use it, it croaks. ??? import math import electronics print electronics.ac_add_a_ph( 10, 0 , 6 , 45 ) Traceback (most recent call last): File stdin, line 1, in ? File f:\devel\python\electronics.py, line 10, in ac_add_a_ph ac1 = complex( amp1 * math.cos( math.radians( ph1 ) ), amp1 * math.sin( math .radians( ph1 ) ) ) NameError: global name 'cos' is not defined That's not what I get when I run it (admittedly, not on windows). I get: import math import electronics print electronics.ac_add_a_ph( 10, 0 , 6 , 45 ) Traceback (most recent call last): File stdin, line 1, in ? File electronics.py, line 13, in ac_add_a_ph amp3 = math.abs( ac3 ) AttributeError: 'module' object has no attribute 'abs' which is exactly what I expected, since abs (which is indeed absolute value) is a built-in function, not a part of the math module. Are you sure the stack trace you posted matches the source code you posted? Well I took the abs( 'complex' ) from the python documentation (python24.chm) section 3.1.1 has the following comment after it '# sqrt(a.real**2 + a.imag**2)' By the way, when using math functions, I find it's usually easier to import them into my namespace by doing from math import *, then I can just use sin(), cos(), etc directly, instead of having to do math.sin() or math.cos(). Especially for common math functions, this makes your code a lot easier to read. Ah, I thought I used to use module functions without the module name. I think my problem is reimporting electronics(.py) after modifications. Yes, now it complains about abs(). looks like enother reason to dump this w2000 installation just so I can install python from scratch and use idle. -- http://mail.python.org/mailman/listinfo/python-list
Re: Problem calling math.cos()
Tim Peters wrote: [Robert Kern] ... ph3 = math.atan( ac3.imag / ac3.real ) ... Don't do that: atan2 is the correct way to compute the angle, because the signs of both inputs are needed to determine the correct quadrant. So do: ph3 = math.atan2(ac3.imag, ac3.real) instead. Hey, I just copied his code to show that it gave a different error than the one he said. I didn't bother to fix it. :-) -- Robert Kern [EMAIL PROTECTED] I have come to believe that the whole world is an enigma, a harmless enigma that is made terrible by our own mad attempt to interpret it as though it had an underlying truth. -- Umberto Eco -- http://mail.python.org/mailman/listinfo/python-list
Re: Looking for resources for making the jump from Java to Python easier and more productive
Take a look at the newgroup archives over the last week or two - there seem to have been a glut of people coming from Java to Python and asking the same sort of questions. There were some links to a bunch of Python 'gotcha' pages which will be useful. For my part, I came from Java to Python, and found that it was useful to do a load of small scripts in the simplest way possible, or in as many different ways possible. For example, trying a script involving creating a new iterable object from a list using for loops, list comprehensions, generators or functional built-ins (such as map()). The clearest method usually seems to be considered the most pythonic. A couple of sites to practice against are: http://www.pythonchallenge.com/ http://mathschallenge.net/ They give a good set of problems which will work various aspects of Python that aren't familiar to Java guys, and also break the mindset that everything has to be done in classes. I'm still making the transition of course ;-) -- http://mail.python.org/mailman/listinfo/python-list
Performance of Python 2.3 and 2.4
Hi!
I was just wondering...
Python 2.3.5 (#2, Mar 6 2006, 10:12:24)
[GCC 4.0.3 20060304 (prerelease) (Debian 4.0.2-10)] on linux2
Type help, copyright, credits or license for more information.
import timeit
a = timeit.Timer('2**1')
b = timeit.Timer('112233445566778899 * 112233445566778899')
a.timeit(1)
5.3986599445343018
b.timeit()
0.59309601783752441
Python 2.4.2 (#2, Nov 20 2005, 17:04:48)
[GCC 4.0.3 2005 (prerelease) (Debian 4.0.2-4)] on linux2
Type help, copyright, credits or license for more information.
import timeit
a = timeit.Timer('2**1')
b = timeit.Timer('112233445566778899 * 112233445566778899')
a.timeit(1)
13.129707813262939
b.timeit()
0.72854804992675781
Why long numbers operations are slower in 2.4?
mk
--
. o . http://joker.linuxstuff.pl
. . o It's easier to get forgiveness for being wrong
o o o than forgiveness for being right.
--
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Re: another question about buffers
In article [EMAIL PROTECTED], [EMAIL PROTECTED] wrote: i think it may be, Moral: don't use arbitrary values as booleans. -- http://mail.python.org/mailman/listinfo/python-list
Re: Can you create an instance of a subclass with an existing instance of the base class?
In article [EMAIL PROTECTED], Sandra-24 [EMAIL PROTECTED] wrote: Now that is a clever little trick. I never would have guessed you can assign to __class__, Python always surprises me in it's sheer flexibility. That's because you're still thinking in OO terms. -- http://mail.python.org/mailman/listinfo/python-list
Re: need a thread to keep a socket connection alive?
thanks for the info, i will likely use the first link you posted with the async module just to get it going, but i want to learn more about twisted for later. there is even an O'Reilly book on it i see. thanks for the tips, sk -- http://mail.python.org/mailman/listinfo/python-list
Re: Performance of Python 2.3 and 2.4
[Michal Kwiatkowski]
I was just wondering...
Python 2.3.5 (#2, Mar 6 2006, 10:12:24)
[GCC 4.0.3 20060304 (prerelease) (Debian 4.0.2-10)] on linux2
Type help, copyright, credits or license for more information.
import timeit
a = timeit.Timer('2**1')
b = timeit.Timer('112233445566778899 * 112233445566778899')
a.timeit(1)
5.3986599445343018
b.timeit()
0.59309601783752441
Python 2.4.2 (#2, Nov 20 2005, 17:04:48)
[GCC 4.0.3 2005 (prerelease) (Debian 4.0.2-4)] on linux2
Type help, copyright, credits or license for more information.
import timeit
a = timeit.Timer('2**1')
b = timeit.Timer('112233445566778899 * 112233445566778899')
a.timeit(1)
13.129707813262939
b.timeit()
0.72854804992675781
Why long numbers operations are slower in 2.4?
In general, they're not. Here on Windows, with those specific examples:
$ type ls.py
import timeit
a = timeit.Timer('2**1')
b = timeit.Timer('112233445566778899 * 112233445566778899')
print a.timeit(1)
print b.timeit()
$ \python23\python ls.py
6.96490123499
0.266523717213
$ \python24\python ls.py
6.81509407621
0.204446820019
So 2.4 is faster on those specific examples here. Some of that's
probably due to code changes, and the rest to that the released
Windows 2.3.5 and 2.4.3 were compiled with different versions of MS's
C compiler, and VC 7.1 happened to do better optimization of the
relevant C code than VC 6.0.
I note that your Pythons were compiled with different (pre)releases of
gcc, so if you want to pursue this the first thing to do is compile
both Pythons with the same gcc. The effectiveness of the platform C's
optimization matters a lot here.
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Re: problems when unpacking tuple ...
On 23/04/2006 2:21 AM, harold wrote: Dear all, Maybe I stared on the monitor for too long, because I cannot find the bug ... You already have your answer, but below are clues on how to solve such problems much faster by yourself. My script transition_filter.py starts with the following lines: import sys for line in sys.stdin : try : for a,b,c,d in line.split() : pass except ValueError , err : print line.split() raise err The output (when given the data I want to parse) is: ['0.0','1','0.04','0'] I doubt it. Much more likely is ['0.0', '1', '0.04', '0'] It doesn't matter in this case, but you should really get into the habit of copy/pasting *EXACTLY* what is there, not re-typing what you think is there. Traceback (most recent call last): File transition_filter.py, line 10, in ? raise err ValueError: need more than 3 values to unpack What is going wrong here? Why does python think that I want to unpack the outcome of line.split() into three values instead of four? I must be really tired, but I just cannot see the problem. Any clues?? Clues: 1. Use the print statement to show what you have. 2. Use the built-in repr() function to show *unambiguously* what you have -- very important when you get into Unicode and encoding/decoding problems; what you see after print foo is not necessarily what somebody using a different locale/codepage will see. 3. In some cases (not this one), it is also helpful to print the type() of the data item. Example: C:\junktype harold.py import sys def harold1(): for line in sys.stdin : try : for a,b,c,d in line.split() : pass except ValueError , err : print line.split() raise err def harold2(): for line in sys.stdin: print line =, repr(line) split_result = line.split() print split result =, repr(split_result) for x in split_result: print about to try to unpack the sequence, repr(x), into 4 items a, b, c, d = x harold2() C:\junkharold.py 0.0 1 0.04 0 a b c d e f ^Z line = '0.0 1 0.04 0\n' split result = ['0.0', '1', '0.04', '0'] about to try to unpack the sequence '0.0' into 4 items Traceback (most recent call last): File C:\junk\harold.py, line 22, in ? harold2() File C:\junk\harold.py, line 20, in harold2 a, b, c, d = x ValueError: need more than 3 values to unpack = Coding style: Not inventing and using your own dialect makes two-way communication much easier in any language (computer or human). Consider reading and following http://www.python.org/dev/peps/pep-0008/ Hope this helps, John -- http://mail.python.org/mailman/listinfo/python-list
Re: howto py2exe/py2app for self updating application
I'm creating a GUI program with wxPython which will be distributed for Mac and Windows. [...] The program should be able to update itself [...] By default, py2exe puts all the .pyc files used in a zip file. The simplest way to do this it let py2exe do what it normally does. Code all of the .py files as you would when running from source (i.e. you'll never explicitly use zipimport). To update, you then: 1. Download the new .pyc files. 2. Expand (use ZipFile) the existing py2exe zip. 3. Replace the old .pyc files with the new ones. 4. Rezip (use ZipFile) the .pyc files. 5. Replace the old py2xe zip with the one containing the new files. 6. Restart the program. This works (I use a more sophisticated version of this) well with py2exe. I haven't used py2app at all, but if it works much like py2exe, then all of the above still applies (certainly the steps are platform-agnostic). =Tony.Meyer -- http://mail.python.org/mailman/listinfo/python-list
Re: Application Generators
Hi walterbyrd, I had also gone through this search earlier, but unfortunately the app generators generate a lot of code, and more imp is that inspite of this, they are not very close to what you really need. I had been evaluating these from time to time. Appgini is good but mostly from an academic view point, you can better learn from its mechanism. Secondly, the kind of app you have in mind, is better hand coded. I recently came accross a similar project, which was eventually done by handcoding. -- http://mail.python.org/mailman/listinfo/python-list
Re: Performance of Python 2.3 and 2.4
Em Dom, 2006-04-23 às 00:20 +0200, Michal Kwiatkowski escreveu:
Hi!
I was just wondering...
Probably there is another factor involved:
$ python2.3
Python 2.3.5 (#2, Mar 6 2006, 10:12:24)
[GCC 4.0.3 20060304 (prerelease) (Debian 4.0.2-10)] on linux2
Type help, copyright, credits or license for more information.
import timeit
timeit.Timer('2**1').timeit(1)
4.6463479995727539
timeit.Timer('112233445566778899 * 112233445566778899').timeit()
0.44853687286376953
$ python2.4
Python 2.4.3 (#2, Mar 30 2006, 21:52:26)
[GCC 4.0.3 (Debian 4.0.3-1)] on linux2
Type help, copyright, credits or license for more information.
import timeit
timeit.Timer('2**1').timeit(1)
4.9987671375274658
timeit.Timer('112233445566778899 * 112233445566778899').timeit()
0.36968302726745605
--
Felipe.
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Re: check whether a value is scalar
Python treats integers as objects, but as I mentioned that I do care about the value only, and not its object methods. I mean that it's not possible to share objects among application in different programming languages, but it's possible to share the scalar values among them. Strings, booleans, integeres, floats, null are types that most programming languages use. Arrays are also commonly used, but each programming language defines and uses it differently, so it's more problematic to treat it as scalar (for example python uses dictionaries while other langs uses regular arrays only). -- http://mail.python.org/mailman/listinfo/python-list
Custom data type in a matrix.
Hi guys. I've been lookig for this in the numpy pdf manual, in this group and on google, but i could not get an answer... Is there a way to create a custom data type (eg: Name: string(30), Age: int(2), married: boolean, etc) and then use that custom data in a matrix? Actually, this is a two question question :P Im doing a simple hex based game and i need a way to store every hex property (color, owner,x, y, etc) in a matrix's cell, representing each cell a hex. Thank you. -- http://mail.python.org/mailman/listinfo/python-list
Re: Custom data type in a matrix.
Gaz wrote:
Hi guys. I've been lookig for this in the numpy pdf manual, in this
group and on google, but i could not get an answer...
You will probably want to look or ask on the numpy list, too.
https://lists.sourceforge.net/lists/listinfo/numpy-discussion
Is there a way to create a custom data type (eg: Name: string(30), Age:
int(2), married: boolean, etc) and then use that custom data in a
matrix? Actually, this is a two question question :P
Yes. Use record arrays. They are discussed in section 8.5 of the _The Guide to
NumPy_ if you have the book. There is another example of using record arrays on
the SciPy wiki (although it is less focused on combining different data types
than it is named column access):
http://www.scipy.org/RecordArrays
Here is an example:
In [18]: from numpy import *
In [19]: rec.fromrecords([['Robert', 25, False], ['Thomas', 53, True]],
names='name,age,married', formats=['S30', int, bool])
Out[19]:
recarray([('Robert', 25, False), ('Thomas', 53, True)],
dtype=[('name', '|S30'), ('age', 'i4'), ('married', '|b1')])
In [21]: Out[19].name
Out[21]:
chararray([Robert, Thomas],
dtype='|S30')
In [22]: Out[19].age
Out[22]: array([25, 53])
In [23]: Out[19].married
Out[23]: array([False, True], dtype=bool)
You can also use object arrays if you need to implement classes and not just
dumb, basic types:
In [33]: class Hex(dict):
: def __init__(self, **kwds):
: dict.__init__(self, **kwds)
: self.__dict__ = self
:
:
In [34]: field = array([Hex(color=(0,0,0), owner='Player1', x=10, y=20,
etc='Black hex owned by Player1'),
:Hex(color=(1,1,1), owner='Player2', x=10, y=21,
etc='White hex owned by Player2')], dtype=object)
In [35]:
In [35]: field
Out[35]: array([{'y': 20, 'etc': 'Black hex owned by Player1', 'color': (0, 0,
0), 'owner': 'Player1', 'x': 10}, {'y': 21, 'etc': 'White hex owned by Player2',
'color': (1, 1, 1), 'owner': 'Player2', 'x': 10}], dtype=object)
--
Robert Kern
[EMAIL PROTECTED]
I have come to believe that the whole world is an enigma, a harmless enigma
that is made terrible by our own mad attempt to interpret it as though it had
an underlying truth.
-- Umberto Eco
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