ANNOUNCE: Python for .NET beta 5 now available
Python for .NET 1.0 beta 5 is now available - you can download it from: http://www.zope.org/Members/Brian/PythonNet/ Python for .NET is a near-seamless integration of Python with the .NET common language runtime. For more details, see the README: http://www.zope.org/Members/Brian/PythonNet/README.html The beta 5 release features a refactoring of thread management support, making the runtime stable for multi-threaded applications, as well as several improvements and bug-fixes. Special thanks to all who sent in thread-related scenarios and test cases! I have tried to incorporate as many of these as possible into the unit tests - if you still have problems that you suspect may be related to threading or interpreter lock issues, please let me know asap. There is also now a mailing list for discussion, questions and issues related to Python for .NET at: [EMAIL PROTECTED] To subscribe to the mailing list or read the online archives, see: http://mail.python.org/mailman/listinfo/pythondotnet Brian Lloyd[EMAIL PROTECTED] V.P. Engineering 540.361.1716 Zope Corporation http://www.zope.com -- http://mail.python.org/mailman/listinfo/python-announce-list Support the Python Software Foundation: http://www.python.org/psf/donations.html
Wanted: New Python Success Stories
Hi, O'Reilly Associates is going to be printing volume III of the Python Success Stories series in June and I'm looking for submissions of new stories. The stories have been quite valuable for people introducing Python to new users and companies. The deadline for me to receive stories for editing is May 1st and the deadline for the final edited, approved story going to O'Reilly is June 1st. The existing stories are online here: http://pythonology.org/success There's more info about writing one here: http://pythonology.org/successguide The biggest hurdle is usually getting approval from the company to write about Python. It may require some educating about open source to get past rules against endorsing commercial products (which Python obviously isn't). If you have any questions, please let me know. Thanks, Stephan Deibel Pythonology.com -- http://mail.python.org/mailman/listinfo/python-announce-list Support the Python Software Foundation: http://www.python.org/psf/donations.html
ReleaseForge 0.6 - A SourceForge project release tool
ReleaseForge 0.6 is now available at: http://releaseforge.sourceforge.net New to version 0.6: * The ability to edit existing SourceForge releases * Some UI tweaks * Some random bug fixes * Some code cleanup * Stays crispy in milk In case you're not already familiar with ReleaseForge: ReleaseForge is a python GUI that allows SourceForge users (project admins and release techs) the ability to create and edit SourceForge releases of their projects. ReleaseForge provides an alternative (re: much improved, more intuitive) interface than the usual SourceForge web interface. ReleaseForge also allows users to create new project packages and update existing packages. ReleaseForge is developed in Python (requires version 2.3 or greater) using PyQt (v3.3 or greater) and contains 100% real fruit juice. A Windows installer is also available that includes all of the software dependencies. http://releaseforge.sourceforge.net -- http://mail.python.org/mailman/listinfo/python-announce-list Support the Python Software Foundation: http://www.python.org/psf/donations.html
Re: Grouping code by indentation - feature or ******?
Op 2005-03-25, Terry Reedy schreef [EMAIL PROTECTED]: Antoon Pardon [EMAIL PROTECTED] wrote in message 1) It makes it hard to see how many levels are dedented at the end of a suite, and sometime makes it difficult to see where the end of a suite is. If e.g. you are looking at the code spread over two pieces of paper, it is sometimes hard to see whether the suite ends at the end of the first page or not. One can use appropriately indented comment lines instead of closing brackets for this purpose. But then we are back at the problem of different styles. People argue they like the python rule, because they have difficulties with the different styles that are allowed by the free form that is allowed in othe languages. 2) It makes it hard to introduce some kind of new syntax constructs. I consider this as much a plus as a minus ;-) I can see your point. We don't want an avalance of new constructs and some restraint is needed but I feel python is too restraint here. 3) Sometimes the structure of the algorithm is not the structure of the code as written, people who prefer that the indentation reflects the structure of the algorithm instead of the structure of the code, are forced to indent wrongly. Do you have any simple examples in mind? Essentially each time I need to use: if condition break. IMO this part of the code is usualy a control for a loop and thus of the same level as while condition: -- Antoon Pardon -- http://mail.python.org/mailman/listinfo/python-list
Re: convert user input to Decimal objects using eval()?
[Julian Hernandez Gomez]
This is maybe a silly question, but...
is there a easy way to make eval() convert all floating
numbers to Decimal objects and return a Decimal?
from decimal import Decimal
import re
number = re.compile(r((\b|(?=\W))(\d+(\.\d*)?|\.\d+)([eE][+-]?\d{1,3})?))
deciexpr = lambda s: number.sub(rDecimal('\1'), s)
for s in ('1.0001+0.111',
'+21.3e-5*85-.1234/81.6',
'1.0/7'):
print '%s\n -- %r' % (s, eval(s))
s = deciexpr(s)
print '%s\n -- %r\n' % (s, eval(s))
1.0001+0.111
-- 1.
Decimal('1.0001')+Decimal('0.111')
-- Decimal(1.)
+21.3e-5*85-.1234/81.6
-- 0.016592745098039215
+Decimal('21.3e-5')*Decimal('85')-Decimal('.1234')/Decimal('81.6')
-- Decimal(0.01659274509803921568627450980)
1.0/7
-- 0.14285714285714285
Decimal('1.0')/Decimal('7')
-- Decimal(0.1428571428571428571428571429)
Raymond Hettinger
--
http://mail.python.org/mailman/listinfo/python-list
Re: Looking for Stephen Turner, maintainer of informixdb
Carsten Haese wrote: Hello everybody: I have discovered that the functionality for connecting Python to an Informix database is currently in a frustrating state of neglect. The link to Kinfxdb is dead, and informixdb doesn't build on Python 2. I couldn't find any usable workarounds to the build problem, so I worked out successfully how to build informixdb using distutils. Now I'd like to share the result with the community, but the maintainer appears to have gone missing. My emails to [EMAIL PROTECTED] and [EMAIL PROTECTED] have bounced back undeliverable, so now I'm posting to the lists trying to locate Stephen. If anybody has any pointers for locating Stephen Turner, please let me know. If Stephen can't be located, I'd be willing to take over the project, but I'd prefer the torch be given to me rather than me just taking it. Carsten, haven't heard anything from Stephen either, but there are some extensions to the informixdb module. I'll send the sources to you next week. So if you like you can bundle everything in one package. Kind greetings, Michael -- http://mail.python.org/mailman/listinfo/python-list
Re: Python for a 10-14 years old?
Joal Heagney wrote: Nice. I still have to download a version of pygame to try this out, but the fact that you can't hide the turtle in python.turtle was bugging me out with my version. (A fair bit of copy/paste in gimp, I can tell you!) What was wrong with hiding the turtle? 'turtle.tracer(False)' usually does it nicely and speeds things up a lot. -- http://mail.python.org/mailman/listinfo/python-list
Re: Calling __init__ with multiple inheritance
Axel Straschil wrote: Thanks to all for the very interesting postings! You're welcome. I came to the following: For single inheritance, super is a nice tool if you will recfactoring the class later. Or if you start out with a diamond inheritance graph from the beginning. For multiple inheritance, if you want to use super, you have to have very much knowledge of the classes you inheritance. For me, OOP is to not have to have the deep inner knowledge of the classes I inheritance from. I failed to bring my point that you need _less_ knowledge across then. Also, for multiple inheritance, if think Mother1.__init__(self, ...) Mother2.__init__(self, ...) Mother3.__init__(self, ...) would be more clear to read then super(MyClass).__init__(Maby this will do some magic thing) For an advantage to show up you need at least three levels of inheritance, see my example with the Parent class. Also, I realy dislike __init__(self, param, **eat_some_needless_stuff) In turn, I really like the name you gave the dictionary parameter :-) Normalize the initializer signature to a common set of arguments. Or pass a single parameter and take the actual information from its attributes. Or write a custom dispatcher, that passes only parameters that correspond to formal arguments... If I later extend my class and also add some parameters to __init__, what will happen to the classes using the baseclass? Also, lool at that: class Mother(object): def __init__(self, param_mother='optional', **eat): print 'Mother' class Father(object): def __init__(self, param_father='optional', **eat): print 'Father' class Child(Mother, Father): def __init__(self, **ham): super(Child, self).__init__(**ham) child = Child(param_mother=1, param_father=1) Father's init will not be called. Change Father/Mother.__init__() to call the superclass initializer. It may be counterintuitive, but it works. Peter -- http://mail.python.org/mailman/listinfo/python-list
Re: How to ensure Maximize button shows in Linux/Unix (Tkinter)
On 26 Mar 2005 08:19:07 -0800, Harlin Seritt [EMAIL PROTECTED] wrote: Diez, Thanks for the quick reply. I am running this under KDE. I actually haven't tried doing so under any other wm for the moment. Any ideas how to get it to show in KDE? This is a tk bug; see: http://sourceforge.net/tracker/index.php?func=detailaid=922336group_id=12997atid=112997 and: http://sourceforge.net/tracker/index.php?func=detailaid=915350group_id=12997atid=112997 The latest tcl/tk 8.4 release may solve the problem, and a patch is provided for the second bug report if you don't want to upgrade. HTH -- python -c 'print .join([chr(154 - ord(c)) for c in U(17zX(%,5.z^5(17l8(%,5.Z*(93-965$l7+-])' -- http://mail.python.org/mailman/listinfo/python-list
Re: itertools to iter transition (WAS: Pre-PEP: Dictionary accumulator methods)
[Jack Diederich]
itertools to iter transition, huh? I slipped that one in, I mentioned
it to Raymond at PyCon and he didn't flinch. It would be nice not to
have to sprinkle 'import itertools as it' in code. iter could also
become a type wrapper instead of a function, so an iter instance could
be a wrapper that figures out whether to call .next or __getitem__
depending on it's argument.
for item in iter(mylist).imap:
print item
or
for item in iter.imap(mylist):
print item
[Steven Bethard]
Very cool idea. I think the transition from
itertools.XXX(iterable, *args, **kwargs)
to
iter.XXX(iterable, *args, **kwargs)
ought to be pretty easy.
Just to make sure you guys can live with your proposed syntax, trying using it
for a month or so and report back on whether the experience was pleasant. Try
dropping the following into your setup.py
def wrapiter():
import __builtin__, itertools
orig = __builtin__.iter
def iter(*args):
return orig(*args)
for name in ('__doc__', '__name__'):
setattr(iter, name, getattr(orig, name))
vars(iter).update(vars(itertools))
__builtin__.iter = iter
wrapiter()
If the experience works out, then all you're left with is the trivial matter of
convincing Guido that function attributes are a sure cure for the burden of
typing import statements.
Raymond Hettinger
--
http://mail.python.org/mailman/listinfo/python-list
Re: a program to delete duplicate files
Why not try to use NoClone, it finds and deletes duplicate files by true byte-by-byte comparison. Smart marker filters duplicate files to delete. With GUI. http://noclone.net Xah Lee wrote: here's a large exercise that uses what we built before. suppose you have tens of thousands of files in various directories. Some of these files are identical, but you don't know which ones are identical with which. Write a program that prints out which file are redundant copies. Here's the spec. -- The program is to be used on the command line. Its arguments are one or more full paths of directories. perl del_dup.pl dir1 prints the full paths of all files in dir1 that are duplicate. (including files in sub-directories) More specifically, if file A has duplicates, A's full path will be printed on a line, immediately followed the full paths of all other files that is a copy of A. These duplicates's full paths will be prefixed with rm string. A empty line follows a group of duplicates. Here's a sample output. inPath/a.jpg rm inPath/b.jpg rm inPath/3/a.jpg rm inPath/hh/eu.jpg inPath/ou.jpg rm inPath/23/a.jpg rm inPath/hh33/eu.jpg order does not matter. (i.e. which file will not be rm does not matter.) perl del_dup.pl dir1 dir2 will do the same as above, except that duplicates within dir1 or dir2 themselves not considered. That is, all files in dir1 are compared to all files in dir2. (including subdirectories) And, only files in dir2 will have the rm prefix. One way to understand this is to imagine lots of image files in both dir. One is certain that there are no duplicates within each dir themselves. (imagine that del_dup.pl has run on each already) Files in dir1 has already been categorized into sub directories by human. So that when there are duplicates among dir1 and dir2, one wants the version in dir2 to be deleted, leaving the organization in dir1 intact. perl del_dup.pl dir1 dir2 dir3 ... does the same as above, except files in later dir will have rm first. So, if there are these identical files: dir2/a dir2/b dir4/c dir4/d the c and d will both have rm prefix for sure. (which one has rm in dir2 does not matter) Note, although dir2 doesn't compare files inside itself, but duplicates still may be implicitly found by indirect comparison. i.e. a==c, b==c, therefore a==b, even though a and b are never compared. -- Write a Perl or Python version of the program. a absolute requirement in this problem is to minimize the number of comparison made between files. This is a part of the spec. feel free to write it however you want. I'll post my version in a few days. http://www.xahlee.org/perl-python/python.html Xah [EMAIL PROTECTED] http://xahlee.org/PageTwo_dir/more.html -- http://mail.python.org/mailman/listinfo/python-list
Re: static variables in functions (was: Version Number Comparison Function)
On 29 Mar 2005 00:29:06 -0800, El Pitonero [EMAIL PROTECTED] wrote: Christos TZOTZIOY Georgiou wrote: One of the previous related threads is this (long URL): http://groups-beta.google.com/group/comp.lang.python/messages/f7dea61a92f5e792,5ce65b041ee6e45a,dbf695317a6faa26,19284769722775d2,7599103bb19c7332,abc53bd83cf8f636,4e87b44745a69832,330c5eb638963459,e4c8d45fe5147867,5a184dac6131a61e?thread_id=84da7d3109e1ee14mode=threadnoheader=1#doc_7599103bb19c7332 Another previous message on this issue: http://groups-beta.google.com/group/comp.lang.lisp/msg/1615d8b83cca5b20 Python's syntax surely is not clean enough for concise metaprogramming. At any rate, I'd agree with Fernando's assessment: Fernando wrote: The real problem with Python is ... Python is going the C++ way: piling feature upon feature, adding bells and whistles while ignoring or damaging its core design. If the core design were better, many new features in Python could have been rendered unnecessary. Do you have specific recommendations that might benefit python 3000? What better core design features would have eliminated what new features? ;-) Regards, Bengt Richter -- http://mail.python.org/mailman/listinfo/python-list
Re: static variables in functions (was: Version Number Comparison Function)
Christos TZOTZIOY Georgiou wrote: One of the previous related threads is this (long URL): http://groups-beta.google.com/group/comp.lang.python/messages/f7dea61a92f5e792,5ce65b041ee6e45a,dbf695317a6faa26,19284769722775d2,7599103bb19c7332,abc53bd83cf8f636,4e87b44745a69832,330c5eb638963459,e4c8d45fe5147867,5a184dac6131a61e?thread_id=84da7d3109e1ee14mode=threadnoheader=1#doc_7599103bb19c7332 Another previous message on this issue: http://groups-beta.google.com/group/comp.lang.lisp/msg/1615d8b83cca5b20 Python's syntax surely is not clean enough for concise metaprogramming. At any rate, I'd agree with Fernando's assessment: Fernando wrote: The real problem with Python is ... Python is going the C++ way: piling feature upon feature, adding bells and whistles while ignoring or damaging its core design. If the core design were better, many new features in Python could have been rendered unnecessary. -- http://mail.python.org/mailman/listinfo/python-list
Re: Calling __init__ with multiple inheritance
Peter Otten wrote: Child() child father mother parent # -- parent only once __main__.Child object at 0x402ad38c D-uh? class Parent(object): def __init__(self): print parent super(Parent, self).__init__() class Father(Parent): def __init__(self): print father super(Father, self).__init__() print D-uh class Mother(Parent): def __init__(self): print mother super(Mother, self).__init__() print D-oh class Child(Father, Mother): def __init__(self): print child super(Child, self).__init__() Child() This prints child father mother parent D-oh D-uh Therefore super is a very intelligent function indeed! jf -- http://mail.python.org/mailman/listinfo/python-list
Re: help with getting selection from wxChoice with out after it has changed
'@'.join([..join(['fred', 'dixon']), ..join(['gmail', 'com'])]) wrote: From: '@'.join([..join(['fred', 'dixon']), ..join(['gmail', 'com'])]) [EMAIL PROTECTED] This is a SyntaxError. You want to enclose the dots with '' marks as well, like this: '@'.join(['.'.join(['fred', 'dixon']), '.'.join(['gmail', 'com'])]) regards, Gerrit Holl. -- Weather in Twenthe, Netherlands 29/03 10:55: 10.0C mist overcast wind 0.9 m/s None (57 m above NAP) -- In the councils of government, we must guard against the acquisition of unwarranted influence, whether sought or unsought, by the military-industrial complex. The potential for the disastrous rise of misplaced power exists and will persist. -Dwight David Eisenhower, January 17, 1961 -- http://mail.python.org/mailman/listinfo/python-list
Re: itertools to iter transition (WAS: Pre-PEP: Dictionary accumulator methods)
Raymond == Raymond Hettinger [EMAIL PROTECTED] writes: Raymond If the experience works out, then all you're left with is Raymond the trivial matter of convincing Guido that function Raymond attributes are a sure cure for the burden of typing Raymond import statements. For one thing, it would make it harder to find the functions from the docs. It's easy to find the doc for 'itertools', but iter object methods would require browsing that infamous Chapter 2 of the documentation... Apart from that, I don't really see the advantage in moving away from itertools. -- Ville Vainio http://tinyurl.com/2prnb -- http://mail.python.org/mailman/listinfo/python-list
Re: Connecting to a SQL Server
Ok. Understood we can interface ADO from python and connect to MS SQL. But still not so clear where SSH comes in? Can elaborate more? Thanks. -- http://mail.python.org/mailman/listinfo/python-list
distance, angle restraint
Hi, all I put more than 10,000 points in a box and then want to getone of many solutions that matches all angle restraints among any 3 points and all distance restraints between any 2 points. How can I achieve this? Please recommend any packages or appropriate methods. Thanks in advance, Biomatics Lab. Department of BiosystemsKorea Advanced Institute of Science and TechnologyYusung-Gu, Taejon 305-333Republic of Korea -- http://mail.python.org/mailman/listinfo/python-list
Re: help with getting selection from wxChoice with out after it has changed
[..join(['fred','dixon'] wrote:
I want to get the selection of several wxChoice boxes.
But i do not want to have to catch the events for all the boxes
I should be able to access the current selection outside of an
event,but i am not seeing how to do this.
#def EvtChoice(self, event):
#print('EvtChoice: %s\n' % event.GetString())
#self.ch.Append(A new item)
#
##-changed here - from event.GetSelection()
#if self.ch.GetSelection() == 'one':
#print('Well done!\n')
Perhaps you are confused by the fact that GetSelection() returns an integer?
Changing the above to either
if self.ch.GetStringSelection() == 'one':
print 'Well done!'
or
if self.ch.GetSelection() == 1:
print 'Well done, too!'
should work as you expect then.
Peter
--
http://mail.python.org/mailman/listinfo/python-list
passing keyword args as a parameter
hi there! this post is somewhat a generalization of one previous question. i was wondering if it is possible to pass an argument list as a parameter to a function. example: def fun_con_pc(pc1 = Ciao!, pc2 = 42): print pc1 print pc2 fun_con_pc() fun_con_pc(pc1 = Addio...) fun_con_pc(pc2 = 666, pc1 = Addio...) arg = 'pc2 = 666, pc1 = Addio...' fun_con_pc(arg) if i execute, i get: Ciao! 42 Addio... 42 Addio... 666 pc2 = 666, pc1 = Addio... 42 **but** i want to get: Ciao! 42 Addio... 42 Addio... 666 Addio... 666 see what i mean? bye macs -- http://mail.python.org/mailman/listinfo/python-list
tkinter destroy()
hi people. when i create a widget, such as a toplevel window, and then i destroy it, how can i test that it has been destroyed? the problem is that even after it has been destroyed, the instance still exists and has a tkinter name, so testing for None is not feasible: import Tkinter fin = None fin1 = Tkinter.Toplevel() fin1.destroy() print fin1 .1075951116 any help? bye macs -- http://mail.python.org/mailman/listinfo/python-list
Re: Queue.Queue-like class without the busy-wait
Op 2005-03-25, Paul Rubin schreef http: Antoon Pardon [EMAIL PROTECTED] writes: Well maybe you could use an os.pipe as a timeout lock then. When the lock is instantiated you put one byte in it. Aquiring the lock is implemented by reading one byte, releasing the lock is implemented by writing a byte. Aquiring the lock with a timeout would make use of select. Hmm, if I understand what you're saying, you'd need a separate pipe for every lock. Interesting idea but I think it would burn too many file descriptors if you used a lot of them. My mentioning select also is showing my age. That was the way of doing short sleeps before usleep became widespread. A signal handler in the main thread could release a lock that the thread is waiting on. This wouldn't work. A thread would have no way knowing for what purpose the lock was released, because the lock was released by the thread holding the lock or because the signal handler released the lock, both would look the same for the thread aquiring the lock. Yes, you'd need a separate lock for each blocked thread. There would be a list of locks waiting for timeouts and the sigalarm handler would release any for which a wakeup was due. You could use a priority queue to maintain the timeout list, so that adding or servicing a timeout would be O(log n). Well have a look at what I have written over the weekend. It uses a seperate thread with one pipe for a wakeup mechanisme. I didn't like using a signal handler because you never know what other modules might have use for signals and how they might interfere. Try it out and let me know what you think. Not thoroughly tested: --- tlock.py -- import threading import os import time from heapq import heappush, heappop from weakref import ref from select import select heapmutex = threading.Lock() heap = [] heappipe = os.pipe() sentinel = 365.25 * 50 * 24 * 3600 # 50 jaar heappush(heap, (time.time() + sentinel, None, None, None)) class _Plock: def __init__(self): self.mutex = threading.Lock() self.broken = False def acquire(self): self.mutex.acquire() def release(self): self.mutex.release() class TimeOut(Exception): pass class Tlock: def __init__(self): self.mutex = threading.Lock() self.locktable = [_Plock()] def acquire(self, timeout=None): self.mutex.acquire() newlock = _Plock() newlock.acquire() self.locktable.append(newlock) prevlock = self.locktable[-2] if len(self.locktable) 2 and timeout is not None: heapmutex.acquire() heappush(heap, (time.time() + timeout, ref(prevlock), self.mutex, self.locktable)) os.write(heappipe[1] , '-') heapmutex.release() self.mutex.release() prevlock.acquire() if prevlock.broken: raise TimeOut, lock timed out def release(self): self.mutex.acquire() self.locktable[0].release() del self.locktable[0] self.locktable[0].release() self.mutex.release() def lock_breaker(): heapfd = heappipe[0] while True: heapmutex.acquire() waketime, pl, mutex, table = heap[0] timeout = waketime - time.time() while timeout = 0.0: lck = pl() if lck is not None: mutex.acquire() try: try: i = table.index(lck, 1) del table[i] lck.broken = True lck.release() # lck.release() except ValueError: pass finally: mutex.release() heappop(heap) waketime, pl, mutex, table = heap[0] timeout = waketime - time.time() heapmutex.release() rdlst, wrlst, erlst = select([heapfd],[],[],timeout) if rdlst: os.read(rdlst[0],1) breaker = threading.Thread(target = lock_breaker) breaker.setDaemon(True) breaker.start() if __name__ == __main__: from time import sleep from random import randint T = Tlock() rg = 5 def thrd(Id): for Nr in xrange(20): try: print Trying %d (loop %d) % (Id, Nr) T.acquire(randint(0,rg)) print Entering %d (loop %d) % (Id, Nr) sleep(randint(0,rg)) print Leaving %d (loop %d) % (Id, Nr) T.release() except TimeOut, ErrId: print Failed %d (loop %d) % (Id, Nr) sleep(randint(0,rg)) for i in xrange(rg): th = threading.Thread(target=thrd, args=(i,)) th.start() -- http://mail.python.org/mailman/listinfo/python-list
tksnack and socket to real time sampling and playing sound
Hi, I try to sample and playback speech using snack. My idea is to have a socket based server that plays back the sound and a client that samples the input from the sound card and sends it to the server using the socket connection. On the snack page there is a tutorial showing a socket server implementation using tcl: http://www.speech.kth.se/snack/tutorial.html I had problems converting that example into python. Googling for such a solution I found one discussion back in 2001: http://groups-beta.google.com/groups?q=tksnack+socketqt_s=Search+Groups The difference with this solution is that it is based around python socket and does not use the snack internal socket implementation for the data input. If I understand that correct there is a limitation as the socket.recv(8192) function limits the receivable data to the specified buffer size. Did somebody use the snack based socket implementation with python? Is there a better way to solve this sampling and playback with another tool than snack? Is snack even capable of doing this? I am looking for pretty low sampling rates, like 8kHz. I would like to be flexible and use it under Windows and Linux as well. TIA Didi -- http://mail.python.org/mailman/listinfo/python-list
Re: Why tuple with one item is no tuple
Op 2005-03-27, Joal Heagney schreef [EMAIL PROTECTED]: Antoon Pardon wrote: snip So python choose a non-deterministic direction. To me (2,3) + (4,5) equals (6,8). I don't dispute that having an operator to combine (2,3) and (4,5) in (2,3,4,5) is usefull, but they should never have used the + for that. (alph, bravo) + (delta, max) -- (alphdelta, bravomax) No, that wouldn't be the result. You are still using + for concatenation, even if only on strings. I say python should have used something else for concatenation (string concatenation included) -- Antoon Pardon -- http://mail.python.org/mailman/listinfo/python-list
Re: Queue.Queue-like class without the busy-wait
Antoon Pardon [EMAIL PROTECTED] writes: Well have a look at what I have written over the weekend. It uses a seperate thread with one pipe for a wakeup mechanisme. Thanks, I'll look at it. Why don't you use usleep instead of a pipe? I decided over the weekend that using a separate thread with usleep is the simplest thing to do in pure Python. If you want to use sigalarm, that should be put in the low level C sigalarm handler so it gets taken care separately from the Python interpreter does anything with the signal. Locks should also be low level primitives. I don't know how this stuff maps onto PyPy but I sincerely hope the looping stuff goes away. Having a series of processing steps connected by queues is a perfectly good way to organize a program, but if there's even just 20 steps, then waiting for all those 50 msec wakeups adds a whole second to the processing latency if the system has been sleeping for a while. The latency really only needs to be in the microseconds on a system with efficient enough threading. -- http://mail.python.org/mailman/listinfo/python-list
Re: Little Q: how to print a variable's name, not its value?
On 28 Mar 2005 22:06:44 -0800, rumours say that [EMAIL PROTECTED] [EMAIL PROTECTED] might have written: snip complete article-- subject is enough Read about locals() and globals() in the Python documentation. These provide the information you request (ie what names are bound to what objects). -- TZOTZIOY, I speak England very best. Be strict when sending and tolerant when receiving. (from RFC1958) I really should keep that in mind when talking with people, actually... -- http://mail.python.org/mailman/listinfo/python-list
Re: Queue.Queue-like class without the busy-wait
Op 2005-03-29, Paul Rubin schreef http: Antoon Pardon [EMAIL PROTECTED] writes: Well have a look at what I have written over the weekend. It uses a seperate thread with one pipe for a wakeup mechanisme. Thanks, I'll look at it. Why don't you use usleep instead of a pipe? Because with the pipe the sleep can be indeterminate. The select make the thread sleep until either of the folowing happens. 1) A timeout, which means one of the locks has to be broken 2) A byte was received. This means a lock was tried to be acquired and inserted in the heap, so the timeout may need to be recalculated. (acquiring a lock, sends a byte over the pipe) I decided over the weekend that using a separate thread with usleep is the simplest thing to do in pure Python. I'm not going to call my solution simple, but it wastes very few cycles. if no thread is blocked on a lock, the select will just block until that changes. No need for some kind of polling loop. -- Antoon Pardon -- http://mail.python.org/mailman/listinfo/python-list
Actor pattern in GUI
Hi, I am trying to grok using actor patterns in a gui as explained here by Andrew Eland: http://www.andreweland.org/code/gui-actor.html The short article explains it using java with which i am not used to at all. But he does provide a python example using pygtk: http://www.andreweland.org/code/gui-actor.py Could anyone look into it and maybe explain it a bit as i don't really get at all what's happening? In addition I am getting these error when I try to run it: GLib-WARNING **: giowin32.c:1654: 3 is neither a file descriptor or a socket GLib-CRITICAL **: g_io_add_watch_full: assertion `channel != NULL' failed GLib-CRITICAL **: g_io_channel_unref: assertion `channel != NULL' failed Any ideas? Thanks... -- http://mail.python.org/mailman/listinfo/python-list
Re: Calling __init__ with multiple inheritance
Hello! Also, lool at that: class Mother(object): def __init__(self, param_mother='optional', **eat): print 'Mother' class Father(object): def __init__(self, param_father='optional', **eat): print 'Father' class Child(Mother, Father): def __init__(self, **ham): super(Child, self).__init__(**ham) child = Child(param_mother=1, param_father=1) Father's init will not be called. Change Father/Mother.__init__() to call the superclass initializer. It may be counterintuitive, but it works. OK, thanks, with the super(...).__init__() in Father/Mother it workes and makes sense. So, the last thing a *realy* don't like ist the __init__(self, param, **ignore_the_rest) thing. Anyone had troubles with that, or should I cust take this as a python way of thinking ... ;-), and getting used to that? Thanks, AXEL. -- Aber naja, ich bin eher der Forentyp. Wolfibolfi's outing in http://www.informatik-forum.at/showpost.php?p=206342postcount=10 -- http://mail.python.org/mailman/listinfo/python-list
Re: Queue.Queue-like class without the busy-wait
Op 2005-03-29, Antoon Pardon schreef [EMAIL PROTECTED]: Op 2005-03-29, Paul Rubin schreef http: Antoon Pardon [EMAIL PROTECTED] writes: Well have a look at what I have written over the weekend. It uses a seperate thread with one pipe for a wakeup mechanisme. Thanks, I'll look at it. Why don't you use usleep instead of a pipe? Because with the pipe the sleep can be indeterminate. The select make the thread sleep until either of the folowing happens. 1) A timeout, which means one of the locks has to be broken 2) A byte was received. This means a lock was tried to be acquired and inserted in the heap, so the timeout may need to be recalculated. (acquiring a lock, sends a byte over the pipe) I decided over the weekend that using a separate thread with usleep is the simplest thing to do in pure Python. I'm not going to call my solution simple, but it wastes very few cycles. if no thread is blocked on a lock, the select will just block until that changes. No need for some kind of polling loop. And here is a small patch for it. It corrects the acquiring and releasing of the heapmutex. --- tlock.py2005-03-29 14:25:09.0 +0200 +++ src/python/tlock.py 2005-03-29 14:25:43.0 +0200 @@ -67,6 +67,7 @@ heapmutex.acquire() waketime, pl, mutex, table = heap[0] timeout = waketime - time.time() +heapmutex.release() while timeout = 0.0: lck = pl() if lck is not None: @@ -82,10 +83,11 @@ pass finally: mutex.release() + heapmutex.acquire() heappop(heap) waketime, pl, mutex, table = heap[0] timeout = waketime - time.time() -heapmutex.release() + heapmutex.release() rdlst, wrlst, erlst = select([heapfd],[],[],timeout) if rdlst: os.read(rdlst[0],1) @@ -107,17 +109,17 @@ for Nr in xrange(20): try: -print Trying %d (loop %d) % (Id, Nr) +print Trying %2d (loop %2d) % (Id, Nr) T.acquire(randint(0,rg)) -print Entering %d (loop %d) % (Id, Nr) +print Entering %2d (loop %2d) % (Id, Nr) sleep(randint(0,rg)) -print Leaving %d (loop %d) % (Id, Nr) +print Leaving %2d (loop %2d) % (Id, Nr) T.release() except TimeOut, ErrId: -print Failed %d (loop %d) % (Id, Nr) +print Failed %2d (loop %2d) % (Id, Nr) sleep(randint(0,rg)) - for i in xrange(rg): + for i in xrange(5 * rg): th = threading.Thread(target=thrd, args=(i,)) th.start() -- http://mail.python.org/mailman/listinfo/python-list
Re: Dumb*ss newbie Q
On Mon, 28 Mar 2005 08:42:22 -0600, Larry Bates wrote: Others have answered your specific question, I thought I would add some suggestions (not tested): 1) You don't need a separate set_title method. You can change the title attribute at any time by just saying m.title=new title. No method is required unless you need to do some pre/post processing. m.title=anything you want 2) To get class to prepare its output, just insert a __str__ method like following: def __str__(self): return 'a href=avi://%s/%s/%s img src=%s%s/tn/%s.jpg/a' % \ (self.audience, self.title, self.driver, self.audience, self.title, self.title) Then you can eliminate the html method and thumb method and just write: print m 3) Add extend keyword arguments for url and audience to the __init__ method. That way you (or other users) will know that each keyword means when they run in Idle or other interpreter that expands keyword arguments on the screen as you are typing): m=Movie(title=Fate_is_the_Hunter, audience=kids, \ driver=X=hermes.seiner.lan:xv,athena.seiner.lan:xmga, \ default:x11;console=vesa) print m If you plan on doing a lot of this you may want to take a look at the htmlgen module at: http://starship.python.net/crew/friedrich/HTMLgen/html/main.html (I actually stole the idea of using the the __str__ method to generate the output from this module). Hope information helps. Thanks, it does. I am trying to write a much simplified album - http://marginalhacks.com/Hacks/album/ . The author has taken it in a direction that is no longer useful to me and I am desparately incompetent in perl Python and I like each other, except that I don't have much experience writing it from scratch For now I am using this tutorial as a go-by: http://www.linuxgazette.com/issue19/python.html, but I will check out the link you provided. --Yan -- use munged address above to email me SpamTrap [EMAIL PROTECTED] -- http://mail.python.org/mailman/listinfo/python-list
MAC changing
Hello, Is it possible to change the MAC address of a packet after I have builded it? I used impacket to build a packet that does not provide the function to change the MAC. Is it possible to set the bytes of the packet where the MAC is stored? I don't want to use system calls to bring the card down and up again with a different MAC, I need to change it in the packet Thank you -- http://mail.python.org/mailman/listinfo/python-list
Re: Queue.Queue-like class without the busy-wait
Op 2005-03-29, Paul Rubin schreef http: Antoon Pardon [EMAIL PROTECTED] writes: I'm not going to call my solution simple, but it wastes very few cycles. if no thread is blocked on a lock, the select will just block until that changes. No need for some kind of polling loop. I think I understand. My original idea was to use a heapq to be able to know exactly when the next pending timeout is due, and usleep for long enough to wake up at just the right time. Then you service the timeout, pop the heap to find when the next timeout after that is, and usleep again. No polling loops and no pipe. But it could be that someone inserts a new timeout while you're sleeping, that's due before you're scheduled to wake up. Your pipe scheme takes care of that, since any thread can write to the pipe and wake up the blocked thread at any time. Right, that is the idea. Really, the culprit here is the weak signalling scheme in Python. There needs to be a way to send signals to threads, or raise asynchronous exceptions in them. There's been some discussion in sourceforge about that, but the issues involved are complex. Well I have raised this issue before and as far as I understand, the big problem seems to be the various kind of behaviour you can get depending on what platform you are working, so writing a module so that python programs behave the same on various platforms seems a hell of a job. So I decided not to pester the python people for this kind of functionality, although I would very much like to have it. I have been playing with the C-API and have somekind of class that allows one thread to raise an excetion in an other but that wouldn't be a solution here, since the raised exception will not manifest itself while the thread is in a C-function. I think the best bet for the short term is handling it at the C level, with sigalarm. Another way is to have chained sigalarm handlers in the main thread. Possible, but I don't have the time to investigate that possibility now. -- Antoon Pardon -- http://mail.python.org/mailman/listinfo/python-list
Secure scripts variables
Hello, given the following situation: I have a script which is readable and executable by a user, but not writable. The users executes the scripts, it reads in a value and based on this value it computes a result and stores it in a variable. Can the user read out the value of this variable? If yes, can he be prevented to do so? (It's a ordinary user on a Linux system with access to the python interpreter.) (Of course: He could just copy the script to a file he has write access and modify it to print the result. It's a theoretical situation.) Thanks, Florian -- http://mail.python.org/mailman/listinfo/python-list
Finding attributes in a list
Hi In a list I have a number of soccer players. Each player has a different rating for attacking, defending, midfield fitness and goalkeeping. I have devised a while loop that goes through this list to find the best player at defending, attacking, midfield and goalkeeping. However there is more than one defender per team so I therefore need it to find the next best player. Below is the code used to ascertain the best defender: # STUFF TO FIND THE TOP DEFENDER defender= 0 # The position of defender is set to the first player in the knowledge base topdefender = 0 c = 3 # the defensive rating of the first player in the list d = (len(squadList)-4) # the defensive rating of the last player in the list. while c = d: if squadList[c] topdefender: topdefender = squadList[c] defender = squadList[c-3] + + squadList[c-2] # The defender variable is assigned to the forename and surname of the player c = c + 8 # Move to the defensive rating of the next player in the list print defender any help on this would be greatly appreciated. thank you -- http://mail.python.org/mailman/listinfo/python-list
Re: [Newbie] How do I get better at Python programming?
In article [EMAIL PROTECTED], Paul Rubin http://[EMAIL PROTECTED] wrote: Anon [EMAIL PROTECTED] writes: I'd like to get to the next level, but I'm not sure how. Are there any suggestions for continuing to learn? How did you guys learn? I'd say look at some more general computer science books, maybe not Python based. This is excellent advice. Software is really about algorithms. Programming languages are just a way to implement those algorithms. But, baby steps first. My suggestion would be: 1) Find some problems in your daily life that you want to solve, and start writing Python programs to solve them (keep in mind, however, that not all problems in life can be solved with software). 2) Hang out on this group and ask good questions (see http://www.catb.org/~esr/faqs/smart-questions.html for some hints on how to do that). 3) After you've spent 6 months or so mastering Python, go learn another language. Which one? I don't know, there are so many good (and bad) choices. Java, I guess. Maybe C# or Visual Basic, or even C++. The particular choice of which is not so important as the decision to learn another one. It's not so much that it's better or worse than Python, but that it's different, and in experiencing the differences you will gain insight into what both of them have in common. 4) Here's the hard part. Every year, for the rest of your programming career, learn another language. Some languages you will learn because they lead to paychecks. Some you will learn because they're cool and different and it's worth exploring the corners of the envelope. Each one will teach you something new about programming. -- http://mail.python.org/mailman/listinfo/python-list
Re: Trouble with RC2
On Mon, 28 Mar 2005 21:32:07 +0200, Do Re Mi chel La Si Do [EMAIL PROTECTED] wrote: Hi ! I have sevral problems with P4-RC2. Typical case, I have a script who run OK with P4 standard ; but, on a new install, with P4-RC2, I obtain : Traceback (most recent call last): File C:\PONX\ponx.py, line 60, in ? import pdebug File C:\PONX\pdebug.py, line 224 for tmpArg in args[1:]: ^ SyntaxError: invalid syntax I'm assuming you mean 2.4 for P4 and 2.4.1c2 for P4-RC2. I can see no changes that should have caused this - without seeing the entire file, I can only assume that you've either got indentation wrong, or you're maybe mixing tabs and spaces? That's the best I can do without seeing the whole file. -- http://mail.python.org/mailman/listinfo/python-list
Re: Which is easier? Translating from C++ or from Java...
[EMAIL PROTECTED] wrote: There is a difference between theory and practice. You know the difference between theory and practice? Well, in theory, there is no difference :-) -- http://mail.python.org/mailman/listinfo/python-list
BF interpreter in Python
Hi, Python is my favorite language, but I rarely get the opertunity to use it at work, so I find myself actively looking for problems to solve with it. Consequently while waiting for C++ build to finish, I wrote a BrainF*** interpreter. If you are not familiar with the BF language see the following example, which calculates the mandlebrot set.. http://esoteric.sange.fi/brainfuck/bf-source/prog/mandelbrot.b My BF interpreter is here.. http://www.willmcgugan.com/brainfuck.py Release to the public domain! I imagine somebody has already done this in Python, and I fully expect some Python expert to give a one line generator expression with the same functionality.. Will McGugan -- http://mail.python.org/mailman/listinfo/python-list
Re: Grouping code by indentation - feature or ******?
Antoon Pardon [EMAIL PROTECTED] wrote: 1) The stuff doesn't has to be spread over multiple pages. One can have 2 functions, each about three quarter of a page. The second function will then cross a page boundary. The advice don't write a function longer than a page is as good advice today as it was 30 years ago, but the definition of a page has changed. In the old days, a page pretty much meant 66 lines, because that's what fit on a standard sheet of line printer paper (minus a few lines for headers and footers). These days, a page pretty much means a window, which are scrollable so your function always starts at the top of one. Of course, there is no standard for how long a window is, but... 2) How long is a page? I have worked in differend kind of environments where the number of lines per page could differ from 35 to 70. I would say 35 to 70 lines seems like a reasonable limit for how long a function should be :-) The system I'm working with now is fill with 500 line functions and 700 line functions. Believe me, 70 lines would be a blessing compared to that. The bottom line is not a rigid line count. The goal is to be able to understand what the function is doing in one gulp. -- http://mail.python.org/mailman/listinfo/python-list
Re: passing keyword args as a parameter
max(01)* [EMAIL PROTECTED] wrote:
see what i mean?
not really, but maybe
arg = {pc2: 666, pc1: Addio...}
fun_con_pc(**arg)
is what you want?
/F
--
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Re: Why tuple with one item is no tuple
Antoon == Antoon Pardon [EMAIL PROTECTED] writes: Antoon Op 2005-03-27, Joal Heagney schreef [EMAIL PROTECTED]: Antoon Pardon wrote: snip So python choose a non-deterministic direction. To me (2,3) + (4,5) equals (6,8). I don't dispute that having an operator to combine (2,3) and (4,5) in (2,3,4,5) is usefull, but they should never have used the + for that. (alph, bravo) + (delta, max) -- (alphdelta, bravomax) Antoon No, that wouldn't be the result. You are still using + Antoon for concatenation, even if only on strings. I say python Antoon should have used something else for concatenation (string Antoon concatenation included) To me, nothing is more natural than ab + cd == abcd. Also [1,2] + [3,4] == [1,2,3,4]. Dot product is not really too useful in real world (non-mathematical) apps. -- Ville Vainio http://tinyurl.com/2prnb -- http://mail.python.org/mailman/listinfo/python-list
Re: Max files in unix folder from PIL process
Hi All-- Rowdy wrote: FreeDB (CD database) stores one file per CD in one directory per category. The misc category/directory on my FreeBSD 5.3 system currently contains around 481,571 small files. The rock directory/category contains 449,208 files. As some have said, ls is *very* slow on these directories, but otherwise there don't seem to be any problems. I assume you're all using Linux. The GNU version of ls does two things that slow it down. The System V and BSD versions were pretty much identical, in that they processed the argv array in whatever order the shell passed it in. The GNU version re-orders the argv array and stuffs all the arguments into a queue. No big deal if you're just doing ls, but for ls multiple directory names it can slow it down for large argv[n] and/or recursive/deep ls. The other thing it does different from SysV/BSD ls is that it provides for default options in an environment variable. If those env settings specify to always use color, that will slow directory processing _way_ down, identically to the -F option. That's because the color and -F options _require_ a stat() on each and every file in the directory. Standard ls with no options (or old SysV/BSD ls that came with no options) works nearly as fast as os.listdir() in Python, because it doesn't require a stat(). The only thing faster, from a shell user's viewpoint, is 'echo *'. That may not be much help;-) Metta, Ivan -- Ivan Van Laningham God N Locomotive Works http://www.andi-holmes.com/ http://www.foretec.com/python/workshops/1998-11/proceedings.html Army Signal Corps: Cu Chi, Class of '70 Author: Teach Yourself Python in 24 Hours -- http://mail.python.org/mailman/listinfo/python-list
good design method calls
I know the answer to this is going to be It depends . . ., but I want to get my mind right. In Fowler's *Refactoring* I read: Older languages carried an overhead in subroutine calls, which deterred people from small methods (followed by the basic Extract Method advice). In Skip Montanaro's Python Performance Tips (http://manatee.mojam.com/~skip/python/fastpython.html) I read: . . . use local variables wherever possible. If the above loop is cast as a function, append and upper become local variables. Python accesses local variables much more efficiently than global variables. These two pieces of advice imply opposite kinds of code revisions. Obviously they have different purposes, and both are right at different times. I wonder if anyone has some wisdom about how to think about when or how often to do which, how to balance them ultimately, and so on. Charles Hartman Professor of English, Poet in Residence the Scandroid is at: http://cherry.conncoll.edu/cohar/Programs http://villex.blogspot.com -- http://mail.python.org/mailman/listinfo/python-list
Re: convert user input to Decimal objects using eval()?
On Tuesday 29 March 2005 03:04, Raymond Hettinger wrote:
from decimal import Decimal
import re
number = re.compile(r((\b|(?=\W))(\d+(\.\d*)?|\.\d+)([eE][+-]?\d{1,3})?))
deciexpr = lambda s: number.sub(rDecimal('\1'), s)
for s in ('1.0001+0.111',
'+21.3e-5*85-.1234/81.6',
'1.0/7'):
print '%s\n -- %r' % (s, eval(s))
s = deciexpr(s)
print '%s\n -- %r\n' % (s, eval(s))
Wow!
Thank you so much!!!
now I can do my simple math function evaluator much more reliable !
Thanks again!
--
Julián
--
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Re: Why tuple with one item is no tuple
Ville == Ville Vainio [EMAIL PROTECTED] writes: Ville To me, nothing is more natural than ab + cd == Ville abcd. Also [1,2] + [3,4] == [1,2,3,4]. Dot product is Ville not really too useful in real world (non-mathematical) Ville apps. ... and of course by dot product, I don't mean dot product at all. I was thinking of summing vectors, which is not that much more common either. -- Ville Vainio http://tinyurl.com/2prnb -- http://mail.python.org/mailman/listinfo/python-list
Optimisation Hints (dict processing and strings)
Hi all, I'd happy to have you share some thougts about ultimate optimisations on those 2 topics: (1)- adding one caractere at the end of a string (may be long) (2)- in a dict mapping a key to a list of int, remove every entrie where the list of int have of length 2 So far, my attempts are for (1): longone=longone + char # where len(char)== 1 I known that string concatenation is time consuming, but a small test on timeit seems to show that packing and creating an array for those 2 elements is equally time consuming for (2): for k in hash.keys()[:]: # Note : Their may be a lot of keys here if len(hash[k])2: del hash[k] Here again, I think the hash.keys duplication can be time *and* memory consuming. But still better than (I suppose - no time it yet) hash=dict([(k,v) for (k,v) in hash if len(v)1]) I know that I can experiment further with timeit, but still would like to hear from your experience. Thanks ! --OPQ -- http://mail.python.org/mailman/listinfo/python-list
Re: [Newbie] How do I get better at Python programming?
1) If you write for MS Windows Get a copy of Python Programming on Win32. 2) Get a copy of Python Cookbook (2nd Edition just shipped). It has 100's of examples with detailed explanations of what the code does. It starts out with very simple recipes but by the end of the book you are covering very advanced techniques. 3) Read the standard library documentation and source code. You can learn a lot. 4) Read this list every day. I learn something daily. Larry Bates Anon wrote: I've gotten off to a good start for programming using Python (my first programming language). I can do the basics (different kinds of loops, variables, functions), but I'm not too good with classes yet. I've written some really small programs just for kicks (most involve statistics of different situations using random numbers). I'd like to get to the next level, but I'm not sure how. Are there any suggestions for continuing to learn? How did you guys learn? -- http://mail.python.org/mailman/listinfo/python-list
Re: Little Q: how to print a variable's name, not its value?
On 28 Mar 2005 23:01:34 -0800, Dan Bishop [EMAIL PROTECTED] wrote: def print_vars(vars_dict=None): ...if vars_dict is None: ... vars_dict = globals() ...for var, value in vars_dict.items(): ... print '%s = %r' % (var, value) ... myPlace = 'right here' myTime = 'right now' print_vars() print_vars = function print_vars at 0x401e0d84 __builtins__ = module '__builtin__' (built-in) myTime = 'right now' myPlace = 'right here' __name__ = '__main__' __doc__ = None Fred = 5 John = 8 Winner = John Both John and Winner are pointing to the literal '8'. Mixing data and program code, ie.. variable names as data, is not a good idea. Dictionaries are one of pythons best features. ;) Ron -- http://mail.python.org/mailman/listinfo/python-list
Re: Secure scripts variables
Florian Lindner wrote: Hello, given the following situation: I have a script which is readable and executable by a user, but not writable. The users executes the scripts, it reads in a value and based on this value it computes a result and stores it in a variable. Can the user read out the value of this variable? Yes. If yes, can he be prevented to do so? Only if the sensitive part of your script runs under different user. See thread about storing passwords in a script: http://groups-beta.google.com/group/comp.lang.python/browse_frm/thread/91e4c114c5114e92 (It's a ordinary user on a Linux system with access to the python interpreter.) If there is a will, there is a way :) I used to run a persistant server on Solaris as ordinary user. The trick is to create an entry in crontab that will periodically (every 10 minutes) check if your server is running, if not, start it up. Note however, after that it's not a good idea to keep sensitive files in your home directory (like your tax forms or browsing history), because if you make an error in your server and it will be hacked, then you risk exposing all your files. Serge. -- http://mail.python.org/mailman/listinfo/python-list
Re: Optimisation Hints (dict processing and strings)
OPQ wrote: I'd happy to have you share some thougts about ultimate optimisations on those 2 topics: (1)- adding one caractere at the end of a string (may be long) longone=longone + char # where len(char)== 1 I known that string concatenation is time consuming, but a small test on timeit seems to show that packing and creating an array for those 2 elements is equally time consuming You've misunderstood the comments about this area. String concatenation is *not* time consuming. *Repeated* concatenations *will become very time consuming*, along an exponential curve. That's what the discussions about O(n^2) are referring to. A single string concatenation is definitely going to be faster than any amount of converting to other data structures and such. Basically, to concatenate two strings, Python simply adds their sizes together and allocates a new memory area of sufficient size, then copies the bytes from each string to the new area. Not much overhead there, for a single concatenation. The problem comes when you try to scale this. At some point, the overhead of allocating and deallocating all the intermediate strings becomes much larger than other approaches would take. For example, by building a list with references to all the strings, then using join(), you save on the intermediate steps. Join performs the length-summation and memory allocation steps only once, and copies each individual string into the final area only once. Much faster, provided the overhead of growing a list as you append() string references is small enough. And it is, since growing a list is not O(n^2) in Python (though I don't recall exactly what it is). The key with this stuff is to realize that neither approach is inherently faster: it depends on how much concatenation you are doing. It could be that concatenating up to four strings is faster than using the append/join technique, or it could be that it's faster up to twenty strings. When you're not talking hundreds of operations, and when you're not talking about actual *measured* performance problems (in other words, when we would call it premature optimization), focus on the readability of the code and on keeping it simple and clean. Worry about the correctness of the code, and leave optimization worries till later. (But understand this big O stuff well enough to be able to avoid the real problem areas, when possible.) -Peter -- http://mail.python.org/mailman/listinfo/python-list
Table of Python Packages, updated
Hello, comp.lang.python, and catalog-sig, Some of you may remember my mail with the very same subject last year. :-) I have continued to maintain the table, and here's the updated result: http://sparcs.kaist.ac.kr/~tinuviel/pypackage/list.cgi 304 Python projects indexed, with links to PyPI, FreeBSD port, Debian deb, Gentoo ebuild, NetBSD pkgsrc, and Fink. Now I am thinking about adding the version tracking. What do you think? If you have any suggestion, correction or omission, please mail me! P.S. I'm not subscribed. Please CC. Seo Sanghyeon -- http://mail.python.org/mailman/listinfo/python-list
Re: Optimisation Hints (dict processing and strings)
OPQ wrote: for (1): longone=longone + char # where len(char)== 1 I known that string concatenation is time consuming, but a small test on timeit seems to show that packing and creating an array for those 2 elements is equally time consuming - use cStringIO instead - or append all chars to a list and do .join (listvar) for (2): for k in hash.keys()[:]: # Note : Their may be a lot of keys here if len(hash[k])2: del hash[k] Here again, I think the hash.keys duplication can be time *and* memory consuming. But still better than (I suppose - no time it yet) hash=dict([(k,v) for (k,v) in hash if len(v)1]) - Try if it isn't faster to iterate using items instead of iterating over keys - use the dict.iter* methods to prevent building a list in memory. You shouldn't use these values directly to delete the entry as this could break the iterator: for key in [k for (k, v) in hash.iteritems () if len (v) 2]: del hash (key) This of course builds a list of keys to delete, which could also be large. - also: hash.keys()[:] is not necessary, hash.keys () is already a copy Daniel -- http://mail.python.org/mailman/listinfo/python-list
Re: good design method calls
Charles Hartman wrote: I know the answer to this is going to be It depends . . ., but I want to get my mind right. In Fowler's *Refactoring* I read: Older languages carried an overhead in subroutine calls, which deterred people from small methods (followed by the basic Extract Method advice). In Skip Montanaro's Python Performance Tips (http://manatee.mojam.com/~skip/python/fastpython.html) I read: . . . use local variables wherever possible. If the above loop is cast as a function, append and upper become local variables. Python accesses local variables much more efficiently than global variables. These two pieces of advice imply opposite kinds of code revisions. Obviously they have different purposes, and both are right at different times. I wonder if anyone has some wisdom about how to think about when or how often to do which, how to balance them ultimately, and so on. While I don't see that Skip's specific comment in any way implies that one should not write functions (doesn't it *say* to write a function?), you are correct at least in the implication that Fowler's advice about creating lots of small functions can carry a performance cost in Python. Python functions have a relatively high setup overhead. On the other hand, most of refactoring is or should be focused on improving the structure of code (removing duplication, improving readability, generalizing, etc) and *not* on improving performance. Why should be? Because in general focusing on improving performance is wasted effort, often with negative results when you look at the big picture. I suspect you've seen the repeated comments in this comp.lang.python about premature optimization (the root of all evil in programming etc. etc.). Optimization rarely *improves* code readability, and often involves a decrease in generality or other tradeoffs. If it conflicts this much with advice from the refactoring world, you'd do well to pay close attention to *why* you are trying to change your code. If it's for performance reasons, then don't pay a lot of attention to the Fowler stuff. Otherwise ignore things like Skip's comment above, and focus on making the code readable. The thing that has helped me most in writing efficient Python is to remember that *I'm using Python*, and it's already rather slower than C for many of the things I do. Why am I using Python? Not for speed, clearly, so worrying about speed is probably a little silly. I use Python because of the readability, because I can write it about ten times faster than I can write in other languages, and because I have access to such a wide array of outstanding libraries that someone else has already optimized. So in the end, my definition of efficient gets revised, I lower my standards to the point where my current code is plenty fast, and I pay attention to the other things Skip says :-) but don't spend a lot of time trying hard to use local variables unless it makes my code more readable in some way. Sorry for the rant... I didn't intend it to head that way when I started out, but I seem to be on a bit of an anti-optimization bent today. :-) -Peter -- http://mail.python.org/mailman/listinfo/python-list
Retrieve Icons Associated To An Extension?
Hello NG, I have searched everyweher, and I am not able to find a solution... basically, I am constructing a GUI with wxPython, in which I have a list. In this list control, I have some file. I would like to associate (to every file) its icon (on Windows). I have searched about the use of Mark Hammond's win32all extensions and also ctypes, but I didn't find a solution. Could anyone please provide a very simple example on how to retrieve an icon associated to a file extension on Windows? Thank you a lot. Andrea. -- Message for the recipient only, if received in error, please notify the sender and read http://www.eni.it/disclaimer/ -- http://mail.python.org/mailman/listinfo/python-list
Re: Table of Python Packages, updated
Seo Hello, comp.lang.python, and catalog-sig, Some of you may remember Seo my mail with the very same subject last year. :-) I have continued Seo to maintain the table, and here's the updated result: Seo http://sparcs.kaist.ac.kr/~tinuviel/pypackage/list.cgi Very nice. I have a couple questions. What do the pink/grey cell backgrounds mean? Would it make sense to add a distutils column for those packages that can be installed from source using python setup.py install, or do you assume that all the listed packages have that capability? Skip -- http://mail.python.org/mailman/listinfo/python-list
Re: tkinter destroy()
Eric Brunel wrote:
On Tue, 29 Mar 2005 10:37:10 GMT, max(01)* [EMAIL PROTECTED] wrote:
hi people.
when i create a widget, such as a toplevel window, and then i destroy
it, how can i test that it has been destroyed? the problem is that even
after it has been destroyed, the instance still exists and has a tkinter
name, so testing for None is not feasible:
import Tkinter
fin = None
fin1 = Tkinter.Toplevel()
fin1.destroy()
print fin1
.1075951116
The winfo_exists method is what you want:
print fin1.winfo_exists()
0
However, I'm curious about *why* you want to do that: since *you* made
the call to destroy, what would you want to do anything with a widget
you've already destroyed?
my main window has a button that opens another toplevel window. this
button is bound to a method that creates the window and does some other
processing *only if* the windows does not exist yet (otherwise, the user
could click more on the button and multiple copies of the window would
pop up, which is not what i want... in fact what i do is to assign None
to a variable called self.dialogo in my main application code, then i do
self.dialogo = Toplevel() inside the method...)
in this precise moment, though, it comes to my mind that i could achieve
the purpose simply activating/deactivating the button according to a flag...
anyway, i attach the code, so you can see better what i mean...
anyone who has to say anything about is welcome of course...
it is a tentative adapration of a program found in the tcl/tk package demo
---cut here---
from Tkinter import *
class MiaApp:
def __init__(self, genitore):
self.mioGenitore = genitore
self.fonte = (Helvetica, 12)
self.fonteVar = (Helvetica, 14)
self.quadro_grande = Frame(genitore)
self.quadro_grande.pack(expand = YES, fill = BOTH)
self.msg = Label(self.quadro_grande)
self.msg.configure(
font = self.fonte,
wraplength = 10c,
justify = LEFT,
text = uSono qui sotto presentati tre pulsanti a spunta. \
Premendo un pulsante, se ne varia lo stato di selezione e si \
imposta una variabile a un valore che indica lo stato del \
pulsante stesso. Premendo il pulsante \u00ABMostra \
Variabili\u00BB si possono vedere i valori correnti delle \
variabili.
)
self.msg.pack(side = TOP)
self.pulsanti = Frame(self.quadro_grande)
self.pulsanti.pack(side = BOTTOM, fill = X, padx = 2m)
self.pulsanti_spunta = Frame(self.quadro_grande)
self.pulsanti_spunta.pack(side = TOP, fill = X, padx = 2m)
self.annulla = Button(self.pulsanti)
self.annulla.configure(
text = Annulla,
command = self.mioGenitore.destroy
)
self.annulla.pack(side = LEFT, expand = YES)
self.var = Button(self.pulsanti)
self.var.configure(
text = Mostra Variabili,
command = self.pulsanteMostraVariabiliPremuto
)
self.var.pack(side = LEFT, expand = YES)
self.tergicristalli = IntVar()
self.b1 = Checkbutton(self.pulsanti_spunta)
self.b1.configure(
text = Tergicristalli a posto,
variable = self.tergicristalli,
relief = FLAT
)
self.b1.pack(
side = TOP,
pady = 2,
anchor = W
)
self.freni = IntVar()
self.b2 = Checkbutton(self.pulsanti_spunta)
self.b2.configure(
text = Freni a posto,
variable = self.freni,
relief = FLAT
)
self.b2.pack(
side = TOP,
pady = 2,
anchor = W
)
self.autista = IntVar()
self.b3 = Checkbutton(self.pulsanti_spunta)
self.b3.configure(
text = Autista sobrio,
variable = self.autista,
relief = FLAT
)
self.b3.pack(
side = TOP,
pady = 2,
anchor = W
)
self.dialogo = None
def mostraVariabili(self, *argomenti):
self.dialogo = Toplevel()
self.dialogo.wm_title(Valori delle variabili)
self.dialogo.quadro_grande = Frame(self.dialogo)
self.dialogo.quadro_grande.pack(expand = YES, fill = BOTH)
self.dialogo.titolo = Label(self.dialogo.quadro_grande)
self.dialogo.titolo.configure(
text = Valori delle variabili:,
width = 20,
font = self.fonteVar
)
self.dialogo.titolo.pack(side = TOP, fill = X)
lung = 1
for i in argomenti:
if len(i) lung:
lung = len(i)
self.dialogo.dq = {}
self.dialogo.dn = {}
self.dialogo.dv = {}
for i in argomenti:
self.dialogo.dq[i] = Frame(self.dialogo.quadro_grande)
self.dialogo.dq[i].pack(
side = TOP,
anchor = W,
fill = X
)
self.dialogo.dn[i] = Label(self.dialogo.dq[i])
self.dialogo.dn[i].configure(
text = i + : ,
width = lung + 2,
anchor = W
)
self.dialogo.dn[i].pack(
side = LEFT
)
self.dialogo.dv[i] = Label(self.dialogo.dq[i])
self.dialogo.dv[i].configure(
textvariable = self.freni, ### FIXME
anchor = W
)
self.dialogo.dv[i].pack(
side = LEFT,
Re: hiding a frame in tkinter
faramarz yari wrote: def do_unpack(f): f.pack_forget() ... b=Button(f3,text=hello,command=do_unpack(f3)) it does not work the interpreter does not claim any error. it works perfectly fine, but it doesn't do what you want. do_unpack(f3) is a function call, so you're calling the function *before* you create the button, and you're then passing the return value (None) to the button widget. if you want to use the function as a callback, use a lambda: b=Button(..., command=lambda: do_unpack(f3)) or a local function def cb(): do_unpack(f3) b=Button(..., command=cb) /F -- http://mail.python.org/mailman/listinfo/python-list
Re: passing keyword args as a parameter
Fredrik Lundh wrote:
max(01)* [EMAIL PROTECTED] wrote:
see what i mean?
not really, but maybe
arg = {pc2: 666, pc1: Addio...}
fun_con_pc(**arg)
is what you want?
precisely! thanks a lot!
macs
--
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Re: Retrieve Icons Associated To An Extension?
[EMAIL PROTECTED] wrote: Hello NG, I have searched everyweher, and I am not able to find a solution... basically, I am constructing a GUI with wxPython, in which I have a list. In this list control, I have some file. I would like to associate (to every file) its icon (on Windows). I have searched about the use of Mark Hammond's win32all extensions and also ctypes, but I didn't find a solution. Could anyone please provide a very simple example on how to retrieve an icon associated to a file extension on Windows? Check out MimeTypesManager in the wxPython demo app (under More Windows/Controls). That seems to do what you want.. Will McGugan -- http://mail.python.org/mailman/listinfo/python-list
serial module NEWBE HELP!
Is this built into any of the python versions? Need it! Using 2.3.5 and doesn't seem to have it.Newbe needs help!email[EMAIL PROTECTED] Thanks Ron -- http://mail.python.org/mailman/listinfo/python-list
Re: Which is easier? Translating from C++ or from Java...
[EMAIL PROTECTED] wrote: Patrick Useldinger wrote: Depends on what language you know best. But Java is certainly easier to read than C++. There's certainly some irony in those last two sentences. However, I agree with the former. It depends on which you know better, the style of those who developed each and so forth. Personally, I'd prefer C++. Not really. If you know none of the languages perfectly, you are less likely to miss something in Java than in C++ (i.e. no , * and stuff in Java). However, if you are much more familiar with one of the two, you're less likely to miss things there. -pu -- http://mail.python.org/mailman/listinfo/python-list
Re: Table of Python Packages, updated
http://sparcs.kaist.ac.kr/~tinuviel/pypackage/list.cgi On Tue, Mar 29, 2005 at 09:30:24AM -0600, Skip Montanaro wrote: Very nice. I have a couple questions. What do the pink/grey cell backgrounds mean? Pink background is not packaged, grey background is in progress. For in progress items, links to (for now) Debian Bug Tracking System, FreeBSD Problem Report, and Gentoo Bugzilla are provided. For the summary line, Debian 208(41) means 208 projects are already packaged, and 41 projects are in the progress of packaging. Would it make sense to add a distutils column for those packages that can be installed from source using python setup.py install or do you assume that all the listed packages have that capability? Are you suggesting linking to the project's homepage, or upstream source tarball? I am not sure whether that makes sense... On the other hand, I think that if there are projects in the table that doesn't use distutils yet, they should be fixed. Seo Sanghyeon -- http://mail.python.org/mailman/listinfo/python-list
Re: Table of Python Packages, updated
Would it make sense to add a distutils column for those packages that can be installed from source using python setup.py install or do you assume that all the listed packages have that capability? Seo Are you suggesting linking to the project's homepage, or upstream Seo source tarball? I am not sure whether that makes sense... Seo On the other hand, I think that if there are projects in the table Seo that doesn't use distutils yet, they should be fixed. That was more what I was getting at, just identification of packages that are installed with distutils. Skip -- http://mail.python.org/mailman/listinfo/python-list
Re: Optimisation Hints (dict processing and strings)
Peter Hansen [EMAIL PROTECTED] writes: You've misunderstood the comments about this area. String concatenation is *not* time consuming. *Repeated* concatenations *will become very time consuming*, along an exponential curve. That's what the discussions about O(n^2) are referring to. For the record, O(n^2) is /not/ exponential, but polynomial. A function with exponential complexity would have, e.g. O(A^n) for some constant A, which would be /much/ worse than the behavior of repeated string concatenation. Regards, -- Aaron Bingham Software Engineer Cenix BioScience GmbH -- http://mail.python.org/mailman/listinfo/python-list
Re: Little Q: how to print a variable's name, not its value?
On Tue, 29 Mar 2005 14:34:39 GMT, Ron_Adam [EMAIL PROTECTED] wrote: On 28 Mar 2005 23:01:34 -0800, Dan Bishop [EMAIL PROTECTED] wrote: def print_vars(vars_dict=None): ...if vars_dict is None: ... vars_dict = globals() ...for var, value in vars_dict.items(): ... print '%s = %r' % (var, value) ... myPlace = 'right here' myTime = 'right now' print_vars() print_vars = function print_vars at 0x401e0d84 __builtins__ = module '__builtin__' (built-in) myTime = 'right now' myPlace = 'right here' __name__ = '__main__' __doc__ = None Fred = 5 John = 8 Winner = John Both John and Winner are pointing to the literal '8'. ummm, yes, of course they are. What's your point? Mixing data and program code, ie.. variable names as data, is not a good idea. Down with eval! Exile exec! A pox on both their houses! (i.e. I respectfully disagree that mixing data with program code is a bad idea) Peace Bill Mill bill.mill at gmail.com -- http://mail.python.org/mailman/listinfo/python-list
Re: Numarray newbie question
Are there no windows binaries for SciPy for python 2.4 yet? I try to run the installer and it complains that it can't find python 2.3. Besides that, vectorize is exactly what i want. -- http://mail.python.org/mailman/listinfo/python-list
truncating a file from the top down
Hi guys, I need to truncate a file from the top down. I imagine doing something like this: if os.stat says the file is too big: read the file trim = only keep the last 2008 bytes (This is where I get stuck) write trim back out to the original file Would someone demonstrate the *best* most efficient way of doing this? Thanks, rbt -- http://mail.python.org/mailman/listinfo/python-list
Re: Numarray newbie question
ChinStrap wrote: Are there no windows binaries for SciPy for python 2.4 yet? I try to run the installer and it complains that it can't find python 2.3. No, not yet. Besides that, vectorize is exactly what i want. -- Robert Kern [EMAIL PROTECTED] In the fields of hell where the grass grows high Are the graves of dreams allowed to die. -- Richard Harter -- http://mail.python.org/mailman/listinfo/python-list
Re: truncating a file from the top down
rbt wrote: if os.stat says the file is too big: read the file trim = only keep the last 2008 bytes (This is where I get stuck) write trim back out to the original file Would someone demonstrate the *best* most efficient way of doing this? if os.stat says the_file is too big: fh = open(the_file, 'rb') fh.seek(2008, 2) data = fh.read() fh.close() assert len(data)==2008 # you may want some error processing here fh = open(the_file, 'wb') fh.write(data) fh.close() /m -- http://mail.python.org/mailman/listinfo/python-list
Re: Numarray newbie question
Oh well. I am downloading all the things to build it, but in the mean time I just did: def get_y_mat(x_ind,y_ind): return self.y_min + y_ind*self.dy def get_x_mat(x_ind,y_ind): return self.x_min + x_ind*self.dx self.x_mat=fromfunction(get_x_mat,matshape) self.y_mat=fromfunction(get_y_mat,matshape) def fxy(x_ind,y_ind): x=self.x_min + x_ind*self.dx y=self.y_min + y_ind*self.dx return f(x,y) def vxy(x_ind,y_ind): x=self.x_min + x_ind*self.dx y=self.y_min + y_ind*self.dx return v(x,y) self.f_mat=fromfunction(fxy,matshape) self.v_mat=fromfunction(vxy,matshape) As you can see I am just repeating calculations in fxy and vxy that I have already done for x_mat and y_mat. This is still faster than saying: self.f_mat = array([f(x,y) for x in x_mat for y in y_mat],matshape) by a noticable amount. -- http://mail.python.org/mailman/listinfo/python-list
Re: Max files in unix folder from PIL process
Yes I'm talking Linux not BSD so with any luck you won't have the same 'ls' issue; it is not a crash but painfully slow. The only other issue I recall is wildcards fail if they encompass too many files (presumably a bash/max command line size). I would expect the various GUI file managers may give unpredictable results; I would also not rely on remotely mounting the bigdir cross-platform. -- http://mail.python.org/mailman/listinfo/python-list
Re: serial module NEWBE HELP!
Ron wrote: Is this built into any of the python versions? Need it! Using 2.3.5 and doesn't seem to have it.Newbe needs help!email[EMAIL PROTECTED] Thanks Ron PySerial has never been built in to any standard v distribution of Python, but it's an easy download and the web page is the first hit in Google if you type python serial... -Peter -- http://mail.python.org/mailman/listinfo/python-list
Re: newbie question
Whats the file that has to be mapped? Can this be a list? Can this list be initialized to 512? Thanks, -SB -- http://mail.python.org/mailman/listinfo/python-list
Python performance tips page moved to wiki
I dumped my old fastpython.html web page: http://manatee.mojam.com/~skip/python/fastpython.html in favor of a page on the Python wiki: http://www.python.org/moin/PythonSpeed/PerformanceTips Now everybody can help fix warts, add content, etc, etc, etc. References to the old page are redirected to the new one. Have at it. Skip -- http://mail.python.org/mailman/listinfo/python-list
Re: Finding attributes in a list
You can use the new 'sorted' built-in function and custom compare
functions to return lists of players sorted according to any criteria:
players = [
... {'name' : 'joe', 'defense' : 8, 'attacking' : 5, 'midfield' : 6,
'goalkeeping' : 9},
... {'name' : 'bob', 'defense' : 5, 'attacking' : 9, 'midfield' : 6,
'goalkeeping' : 3},
... {'name' : 'sam', 'defense' : 6, 'attacking' : 7, 'midfield' : 10,
'goalkeeping' : 4}
... ]
def cmp_attacking(first, second):
... return cmp(second['attacking'], first['attacking'])
...
[p['name'] for p in sorted(players, cmp_attacking)]
['bob', 'sam', 'joe']
--
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Re: xml marshal of general (but non Python standard) class
Thank you Martin. I had not considered pickle, and I've done my
research. However, I'm still having problems:
Your foo class (for pickle and xml dumps) works fine for me.
f=Foo()
f.thanksTo='Martin'
f.howMany=100
pickle.dumps(f)
(i__main__\nFoo\np0\n(dp1\nS'thanksTo'\np2\nS'Martin'\np3\nsS'howMany'\np4\nI100\nsb.
But for my identifiedPeaks class (for instance), it has trouble. This
class contains a list of peak classes IdentifiedPeaks.Peak...
from IdentifiedPeaks import IdentifiedPeaks
identifiedPeaks=IdentifiedPeaks()
identifiedPeaks.read(open('input/analysisReport.txt'))
pickle.dumps(identifiedPeaks)
Traceback (most recent call last):
File stdin, line 1, in ?
File /usr/lib/python2.3/pickle.py, line 1386, in dumps
Pickler(file, protocol, bin).dump(obj)
File /usr/lib/python2.3/pickle.py, line 231, in dump
self.save(obj)
File /usr/lib/python2.3/pickle.py, line 338, in save
self.save_reduce(obj=obj, *rv)
File /usr/lib/python2.3/pickle.py, line 433, in save_reduce
save(state)
File /usr/lib/python2.3/pickle.py, line 293, in save
f(self, obj) # Call unbound method with explicit self
File /usr/lib/python2.3/pickle.py, line 663, in save_dict
self._batch_setitems(obj.iteritems())
File /usr/lib/python2.3/pickle.py, line 677, in _batch_setitems
save(v)
File /usr/lib/python2.3/pickle.py, line 293, in save
f(self, obj) # Call unbound method with explicit self
File /usr/lib/python2.3/pickle.py, line 614, in save_list
self._batch_appends(iter(obj))
File /usr/lib/python2.3/pickle.py, line 629, in _batch_appends
save(x)
File /usr/lib/python2.3/pickle.py, line 338, in save
self.save_reduce(obj=obj, *rv)
File /usr/lib/python2.3/pickle.py, line 415, in save_reduce
save(args)
File /usr/lib/python2.3/pickle.py, line 293, in save
f(self, obj) # Call unbound method with explicit self
File /usr/lib/python2.3/pickle.py, line 576, in save_tuple
save(element)
File /usr/lib/python2.3/pickle.py, line 293, in save
f(self, obj) # Call unbound method with explicit self
File /usr/lib/python2.3/pickle.py, line 760, in save_global
raise PicklingError(
pickle.PicklingError: Can't pickle class 'IdentifiedPeaks.Peak': it's
not found as IdentifiedPeaks.Peak
xml.marshal has the problem I mentioned before...
xml.marshal.generic.dumps(identifiedPeaks)
Traceback (most recent call last):
File stdin, line 1, in ?
File /usr/lib/python2.3/site-packages/_xmlplus/marshal/generic.py,
line 59, in dumps
L = [self.PROLOGUE + self.DTD] + self.m_root(value, dict)
File /usr/lib/python2.3/site-packages/_xmlplus/marshal/generic.py,
line 104, in m_root
L = ['%s' % name] + self._marshal(value,dict) + ['/%s' % name]
File /usr/lib/python2.3/site-packages/_xmlplus/marshal/generic.py,
line 92, in _marshal
return getattr(self, meth)(value, dict)
AttributeError: Marshaller instance has no attribute
'm_IdentifiedPeaks'
Help would be hugely appreciated.
--
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Re: good design method calls
On Mar 29, 2005, at 10:36 AM, Peter Hansen wrote: Sorry for the rant... I didn't intend it to head that way when I started out, but I seem to be on a bit of an anti-optimization bent today. :-) No, that's very helpful; thanks. Charles Hartman -- http://mail.python.org/mailman/listinfo/python-list
problem with tkinter
hello.
the following code:
1 from Tkinter import *
2
3 class MiaApp:
4 def __init__(self, genitore):
5 self.mioGenitore = genitore
6 self.i = IntVar()
7 self.i.set(42)
8 self.s = StringVar()
9 self.s.set(Baobab)
10 self.lab = {}
11 self.lab[self.i] = Label(self.mioGenitore)
12 self.lab[self.i].configure(width = 30, relief = RIDGE,
13 text = [vuota])
14 self.lab[self.i].pack()
15 self.lab[self.s] = Label(self.mioGenitore)
16 self.lab[self.s].configure(width = 30, relief = RIDGE,
17 text = [vuota])
18 self.lab[self.s].pack()
19 self.but = Button(self.mioGenitore)
20 self.but.configure(text = Vai!, command = self.procedi)
21 self.but.pack()
22 def procedi(self):
23 for var in (self.i, self.s):
24 self.lab[var].configure(textvariable = var)
25
26 radice = Tk()
27 miaApp = MiaApp(radice)
28 radice.mainloop()
is intended
--
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Re: truncating a file from the top down
Mike Rovner wrote: if os.stat says the_file is too big: fh = open(the_file, 'rb') fh.seek(2008, 2) should be fh.seek(-2008, 2) right? data = fh.read() fh.close() assert len(data)==2008 # you may want some error processing here fh = open(the_file, 'wb') fh.write(data) fh.close() or if os.path.getsize(the_file) TOO_BIG: fh = open(the_file, 'rb+') fh.seek(-2008, 2) data = fh.read() fh.seek(0) # rewind fh.write(data) fh.truncate() fh.close() /F -- http://mail.python.org/mailman/listinfo/python-list
problem with tkinter
hello.
the following code:
1 from Tkinter import *
2
3 class MiaApp:
4 def __init__(self, genitore):
5 self.mioGenitore = genitore
6 self.i = IntVar()
7 self.i.set(42)
8 self.s = StringVar()
9 self.s.set(Baobab)
10 self.lab = {}
11 self.lab[self.i] = Label(self.mioGenitore)
12 self.lab[self.i].configure(width = 30, relief = RIDGE,
13 text = [vuota])
14 self.lab[self.i].pack()
15 self.lab[self.s] = Label(self.mioGenitore)
16 self.lab[self.s].configure(width = 30, relief = RIDGE,
17 text = [vuota])
18 self.lab[self.s].pack()
19 self.but = Button(self.mioGenitore)
20 self.but.configure(text = Vai!, command = self.procedi)
21 self.but.pack()
22 def procedi(self):
23 for var in (self.i, self.s):
24 self.lab[var].configure(textvariable = var)
25
26 radice = Tk()
27 miaApp = MiaApp(radice)
28 radice.mainloop()
is intended to make a window with 2 labels and a button, such that
pressin the button you get the labels display the content of two
variables. it does not work, of course, as intended. is there anybody
who can point me in the right direction? (the problem seems to be that
the command option wants a variable name, not a string containing that
name).
hopefully
macs
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Wanted: New Python Success Stories
Hi, O'Reilly Associates is going to be printing volume III of the Python Success Stories series in June and I'm looking for submissions of new stories. The stories have been quite valuable for people introducing Python to new users and companies. The deadline for me to receive stories for editing is May 1st and the deadline for the final edited, approved story going to O'Reilly is June 1st. The existing stories are online here: http://pythonology.org/success There's more info about writing one here: http://pythonology.org/successguide The biggest hurdle is usually getting approval from the company to write about Python. It may require some educating about open source to get past rules against endorsing commercial products (which Python obviously isn't). If you have any questions, please let me know. Thanks, Stephan Deibel Pythonology.com -- http://mail.python.org/mailman/listinfo/python-list
Problem in designing a global directory in python
I want to create a object directory called Context in my program, which is based on a dict to save and retrieve values/objects by string-type name. I have the definition like this: utils.py global sysctx class Context: def __init__(self): def set(self, name, obj, overwrite=True): def get(self, name): def has(self, name): def init(): global sysctx sysctx = Context() def getContext(): global sysctx return sysctx - init() is called somewhere at the beginning of the program. In other modules, i want to use this in the following manner, from utils import * getContext().set(...) but SOMETIMES I met following error located in getContext() NameError: global name 'sysctx' is not defined I found that when a module is in the same directory as utils.py, when I can simply use utils for importing, there is no such problem. But when i was writing a module in a deeper directory than utils.py, which has to use the full module name for importing, such as: from myproj.utils import * getContext().set(...) I got this error. What should I do to correct that? -- http://mail.python.org/mailman/listinfo/python-list
Re: Distributing closed source modules
Fuzzyman wrote: Dave Brueck wrote: By futile I meant that, if the code ends up running on a user's machine, then a sufficiently motivated person could crack it wide open, regardless of implementation language - the only way to truly protect the code is to never let it out of your hands (i.e. it's accessible just via a web service). I understand what you are saying - using hte word 'futilew' implies that code is *likely* to be broken, not that it is *theoretically possible* for it to be broken. If code has a small user base it is probable that there is plenty that can be done to make breaking the code a lot harder. There are also legitimate reasons why someone would want to do this. 'Futile' is definitely a misleading response :-)3 Not really. For all practical purposes, shipping .pyc files is probably sufficient for most of the software out there: (1) it's a high enough fence for almost all users, (2) for most programs, getting the source code and being able to do something with it are two very different things, and (3) for most programs, there really is no proprietary magic worth protecting. So, when somebody says it's not good enough, and they need something better, I have to admit I'm initially skeptical of their perceived need for better protection of the source code (there _are_ some cases where it should be protected, but they are much less common than people seem to think). One of two things is probably true in these cases: 1) The value of the source code is overestimated - yes, it's a nice program, but there's not really anything in there to warrant the higher development/deployment/debugging costs associated with more security. As such, nobody is really going to care enough to crack the code. And if anybody does, it's unlikely that they'll actually do anything with the code. Thus, the effort to secure the code more is futile - it's ineffective because the effort will never provide any benefit. OR 2) The code really does have some innovative, proprietary algorithm, like a video codec with wildly improved compression (that for some reason you've implemented in pure Python ;-) ). If the value of the code is really high, then no amount of security is going to prevent people from getting at it - trying to protect your code is futile because no matter how high a wall you create, sufficiently determined people will climb over it. Plus, protecting the source code may be the least of your worries (if they're willing to steal your code, they may just as well be willing to use your library illegally, etc.). It's a question that often comes up on comp.lang.python - and the reply is often don't bother, it's not possible - and why do you want to do that anyway. This is a response that is likely to turn people towards other languages Perhaps the response could be framed better, but at the same time it _is_ a pretty honest response, and maybe Python really _isn't_ the language for such people. It's just like people who ask for curly braces - Python is not the language for them. So if I asked for braces, a lot of the c.l.py responses would be geared towards helping me understand that they aren't really needed, but if I insist that I have to have them, then maybe Python isn't for me. :) So, when the question comes up, I don't mind offering some suggestions, but the suggestions will always include the disclaimer that it's probably a waste of time effort - IMO leaving that part out would be misleading. -Dave -- http://mail.python.org/mailman/listinfo/python-list
Re: Little Q: how to print a variable's name, not its value?
In article [EMAIL PROTECTED], Bill Mill [EMAIL PROTECTED] wrote: . . . (i.e. I respectfully disagree that mixing data with program code is a bad idea) . . . Most applications (as opposed to system) developers should be doing it rarely. VERY often when they seem inclined to do so, it's just a symptom of a confused design. In no way do I mean to restrict knowledgeable metaclass authors, LISPers, debugger inventors, or other legitimate exceptions to my claim. -- http://mail.python.org/mailman/listinfo/python-list
Re: Problem in designing a global directory in python
Le 29 Mar 2005 09:50:46 -0800, Tian a écrit :
I want to create a object directory called Context in my program, which
is based on a dict to save and retrieve values/objects by string-type
name. I have the definition like this:
utils.py
global sysctx
# you are in the global scope of the utils module. This global sysctx
# has no meaning, replace by
sysctx = None # create a global 'sysctx' name in utils namespace
class Context:
class Context(object): # why not use new-style classes, we are in
2005
def __init__(self):
# I suppose that there is some __doc__ and code :-)
def set(self, name, obj, overwrite=True):
def get(self, name):
def has(self, name):
def init():
global sysctx
sysctx = Context()
def getContext():
global sysctx
return sysctx
-
init() is called somewhere at the beginning of the program.
In other modules, i want to use this in the following manner,
from utils import *
Please do not use the from module import * form
from utils import getContext
getContext().set(...)
You can also restrict the exported names of utils.py by adding a
__all__ = ('getContext',)
in utils.py.
but SOMETIMES I met following error located in getContext()
NameError: global name 'sysctx' is not defined
I found that when a module is in the same directory as utils.py, when I
can simply use utils for importing, there is no such problem. But
when i was writing a module in a deeper directory than utils.py, which
has to use the full module name for importing, such as:
from myproj.utils import *
getContext().set(...)
I got this error.
What should I do to correct that?
See above :-) and post a follow-up to report if the issue is solved.
PS sorry for bad english. I am not a native speaker.
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Re: itertools to iter transition (WAS: Pre-PEP: Dictionary accumulator methods)
Ville Vainio wrote: Raymond == Raymond Hettinger [EMAIL PROTECTED] writes: Raymond If the experience works out, then all you're left with is Raymond the trivial matter of convincing Guido that function Raymond attributes are a sure cure for the burden of typing Raymond import statements. For one thing, it would make it harder to find the functions from the docs. It's easy to find the doc for 'itertools', but iter object methods would require browsing that infamous Chapter 2 of the documentation... Well, it would only make them as hard to find as, say, dict.fromkeys, which is probably the best parallel here. Of course iter would have to be documented as a builtin type. I don't find the argument builtin type methods are hard to find convincing -- the solution here is to fix the documentation, not refuse to add builtin types. Apart from that, I don't really see the advantage in moving away from itertools. True it's not a huge win. But I'd argue that for the same reasons that dict.fromkeys is a dict classmethod, the itertools methods could be iter classmethods (or staticmethods). The basic idea being that it's nice to place the methods associated with a type in that type's definiton. The parallel's a little weaker here because calling iter doesn't always produce objects of type iter: py class C(object): ... def __iter__(self): ... yield 1 ... py iter(C()) generator object at 0x011805A8 But note that iter does produce 'iterator' objects for the old __getitem__ protocol: py class C(object): ... def __getitem__(self, index): ... if index 5: ... raise IndexError ... return index ... py iter(C()) iterator object at 0x01162EF0 I guess the real questions are[1]: * How much does iter feel like a type? * How closely are the itertools functions associated with iter? STeVe [1] There's also the question of how much you believe in OO tenets like functions closely associated with a type should be members of that type... -- http://mail.python.org/mailman/listinfo/python-list
Re: [Newbie] How do I get better at Python programming?
Roy Smith wrote: keep in mind, however, that not all problems in life can be solved with software. +1 QOTW -- Website: www DOT jarmania FULLSTOP com -- http://mail.python.org/mailman/listinfo/python-list
Re: truncating a file from the top down
Right. Thanks for the correction. Fredrik Lundh wrote: Mike Rovner wrote: if os.stat says the_file is too big: fh = open(the_file, 'rb') fh.seek(2008, 2) should be fh.seek(-2008, 2) right? data = fh.read() fh.close() assert len(data)==2008 # you may want some error processing here fh = open(the_file, 'wb') fh.write(data) fh.close() or if os.path.getsize(the_file) TOO_BIG: fh = open(the_file, 'rb+') fh.seek(-2008, 2) data = fh.read() fh.seek(0) # rewind fh.write(data) fh.truncate() fh.close() /F -- http://mail.python.org/mailman/listinfo/python-list
Re: Little Q: how to print a variable's name, not its value?
On Tue, 29 Mar 2005 18:08:04 GMT, Cameron Laird [EMAIL PROTECTED] wrote: In article [EMAIL PROTECTED], Bill Mill [EMAIL PROTECTED] wrote: . . . (i.e. I respectfully disagree that mixing data with program code is a bad idea) . . . Most applications (as opposed to system) developers should be doing it rarely. VERY often when they seem inclined to do so, it's just a symptom of a confused design. On that point I can agree. I just wanted to say that there are valuable uses for mixing code and data. As soon as I sent my email out, I realized that I meant to say that mixing data with program code is *not always* a bad idea. Particularly, yelling at this guy for wanting to figure out a variable's name is, I think, overzealous. If he just wants to use it for debugging, then I don't know why he needs to be shouted down. In no way do I mean to restrict knowledgeable metaclass authors, LISPers, debugger inventors, or other legitimate exceptions to my claim. I'm confused. Are you ron_adam, cameron laird, or both? Either way, your point is well taken, and I should have been clearer in my overly glib email. Peace Bill Mill bill.mill at gmail.com -- http://mail.python.org/mailman/listinfo/python-list
Re: modes for AES encryption?
Chris Curvey wrote: I'm trying to use the AES module in the Python Cryptography Toolkit. I need to set the mode to ECB/NoPadding, and there's a reference to a Mode parameter in the new() function, but no examples for AES. Who can point me in the right direction? Answering my own question for posterity...ECB is your *only* option for AES, and you have to do your own padding (pad with \0 to emulate NoPadding). -- http://mail.python.org/mailman/listinfo/python-list
Re: code for Computer Language Shootout
We've made it somewhat easier to contribute programs. No need to subscribe to the mailing-list. No need for a user-id or login. See the FAQ How can I contribute a program? http://shootout.alioth.debian.org/faq.php -- http://mail.python.org/mailman/listinfo/python-list
Re: xml marshal of general (but non Python standard) class
syd wrote: But for my identifiedPeaks class (for instance), it has trouble. This class contains a list of peak classes IdentifiedPeaks.Peak... What precisely is the name of the class. You say it is IdentifiedPeaks.Peak, but... from IdentifiedPeaks import IdentifiedPeaks Here you import IdentifiedPeaks.IdentifiedPeaks, not IdentifiedPeak.Peak. pickle.PicklingError: Can't pickle class 'IdentifiedPeaks.Peak': it's not found as IdentifiedPeaks.Peak Here it claims there is no class IdentifiedPeaks.Peak, and I tend to believe it. Could it be that this class does not exist under this name? Python needs to pickle the full class name so that unpickle can find the class. It uses (klass.__module__).(klass.__name__); if the class is nested in another class, pickle cannot find out. So I suggest to move the Peak class toplevel into the module. My guess is that it is nested inside IdentifiedPeaks. The simplest fix might be be to put Peak=IdentifiedPeaks.Peak into IdentifiedPeaks.py; better would be to move the class. AttributeError: Marshaller instance has no attribute 'm_IdentifiedPeaks' That would happen if IdentifiedPeaks is a new-style class (i.e. inheriting from object). marshal has only generic support for instance objects; each additional type needs separate support. You can provide that support by inheriting from Marshaller, adding m_ functions for all missing types. Each function needs to return a list of XML substrings, e.g. through def m_IdentifiedPeaks(self, peaks, dict): L = [ 'IdentifiedPeaks' ] for p in peaks.getPeaks(): L += self._marshal(p) L += [ '/IdentifiedPeaks' ] return L The dict parameter keeps the object references for cycle and shared reference detection. Whether or not you need cycle support depends on your application. Alternatively, patches to support new-style classes in a more general way are welcome. Regards, Martin -- http://mail.python.org/mailman/listinfo/python-list
Re: Problem in designing a global directory in python
I have tried using sysctx=None instead of global sysctx, but it doesn't work either. It seems my initialization work in the previous calling of init() has no persistent effect when utils is imported using from myproj.utils import getContext. What's weird, when a module is in the same directory as utils.py, where I can simply use utils for importing, there is no such problem. Any other suggestions? -- http://mail.python.org/mailman/listinfo/python-list
Re: good design method calls
On Tue, 29 Mar 2005 09:09:37 -0500, Charles Hartman [EMAIL PROTECTED] wrote: I know the answer to this is going to be It depends . . ., but I want to get my mind right. In Fowler's *Refactoring* I read: Older languages carried an overhead in subroutine calls, which deterred people from small methods (followed by the basic Extract Method advice). In Skip Montanaro's Python Performance Tips (http://manatee.mojam.com/~skip/python/fastpython.html) I read: . . . use local variables wherever possible. If the above loop is cast as a function, append and upper become local variables. Python accesses local variables much more efficiently than global variables. These two pieces of advice imply opposite kinds of code revisions. Obviously they have different purposes, and both are right at different times. I wonder if anyone has some wisdom about how to think about when or how often to do which, how to balance them ultimately, and so on. Charles Hartman Professor of English, Poet in Residence the Scandroid is at: http://cherry.conncoll.edu/cohar/Programs http://villex.blogspot.com It depends... ;) Converting small functions to inline, usually should only be done in the inner most loops to optimize performance if it's needed. Moving calculations out of those loops by doing them ahead of time is also good. It's good practice in python to put all of your code in functions or class's even if it's a single main() function. def main() (program code) main() Then you avoid the slower globals unless you declare them with the global statement. If main, or any other functions, get too big or complex, split them up as needed. Ron -- http://mail.python.org/mailman/listinfo/python-list
Re: Which is easier? Translating from C++ or from Java...
Hey all: Thanks for the responses... I've found a third open source implementation in pascal (delphi), and was wondering how well that would translate to python? -cjl -- http://mail.python.org/mailman/listinfo/python-list
Re: truncating a file from the top down
Mike Rovner wrote: Right. Thanks for the correction. Fredrik Lundh wrote: Mike Rovner wrote: if os.stat says the_file is too big: fh = open(the_file, 'rb') fh.seek(2008, 2) should be fh.seek(-2008, 2) right? data = fh.read() fh.close() assert len(data)==2008 # you may want some error processing here fh = open(the_file, 'wb') fh.write(data) fh.close() or if os.path.getsize(the_file) TOO_BIG: fh = open(the_file, 'rb+') fh.seek(-2008, 2) data = fh.read() fh.seek(0) # rewind fh.write(data) fh.truncate() fh.close() /F Thanks for the info guys! -- http://mail.python.org/mailman/listinfo/python-list
cgi and multipart/form-data?
I have a form like this: form method=post enctype=multipart/form-data input type=file name=myFile input type=text name=foo input type=submit /form When I submit this form to my Python script using the CGI module, I seem to get the myFile variable, but I don't seem to the foo variable. Interestingly, if I take out the myFile variable (or specify a much smaller file) I do get the value for foo. The files that I'm trying to handle are 400-500Kb in size...is there something I need to do (cgi.maxlen?) to let cgi handle big files? -- http://mail.python.org/mailman/listinfo/python-list
Re: Problem in designing a global directory in python
Tian a écrit : I want to create a object directory called Context in my program, which is based on a dict to save and retrieve values/objects by string-type name. I have the definition like this: utils.py global sysctx class Context: def __init__(self): def set(self, name, obj, overwrite=True): def get(self, name): def has(self, name): def init(): global sysctx sysctx = Context() def getContext(): global sysctx return sysctx Why using a (not so) global variable here ? If your problem is to make sure you have only one instance of Context in your program, there are cleaner solutions - one of them being a Singleton (you'll find all needed doc and exemples on the net - google is your friend !-). -- http://mail.python.org/mailman/listinfo/python-list
Need Help: Server to pass py objects
I have a legacy system with data stored in binary files on a remote server. I need to access and modify the content of those files from a webserver running on a different host. (All Linux) I would like to install a server on the legacy host that would use my python code to translate between the legacy files and Python Objects that represent the subset of data I care about, then pass those Python objects back and forth to my webserver, which would then manage the http I/F to various clients. My organization prefers to use open source software. Can anyone suggest some products to research further? -- http://mail.python.org/mailman/listinfo/python-list
