python-graph-1.6.0 released
python-graph release 1.6.0 http://code.google.com/p/python-graph/ python-graph is a library for working with graphs in Python. This software provides a suitable data structure for representing graphs and a whole set of important algorithms. The code is appropriately documented and API reference is generated automatically by epydoc. Provided features and algorithms: * Support for directed, undirected, weighted and non-weighted graphs * Support for hypergraphs * Canonical operations * XML import and export * DOT-Language output (for usage with Graphviz) * Random graph generation * Accessibility (transitive closure) * Breadth-first search * Critical path algorithm * Cut-vertex and cut-edge identification * Depth-first search * Heuristic search (A* algorithm) * Identification of connected components * Minimum spanning tree (Prim's algorithm) * Mutual-accessibility (strongly connected components) * Shortest path search (Dijkstra's algorithm) * Topological sorting * Transitive edge identification The 1.6.x series is our refactoring series. Along the next releases, we'll change the API so we can better prepare the codebase to new features. If you want a softer, directed transition, upgrade your code to every release in the 1.6.x series. On the other hand, if you'd rather fix everything at once, you can wait for 1.7.0. Download: http://code.google.com/p/python-graph/downloads/list (tar.bz2, zip and egg packages are available.) Installing: If you have easy_install on your system, you can simply run: # easy_install python-graph -- http://mail.python.org/mailman/listinfo/python-announce-list Support the Python Software Foundation: http://www.python.org/psf/donations.html
ANN: Webware for Python 1.0.2 released
Webware for Python 1.0.2 has been released. This is the second bugfix release for Webware for Python release 1.0, mainly fixing some problems and shortcomings of the PSP plug-in. See the WebKit and PSP release notes for details. Webware for Python is a suite of Python packages and tools for developing object-oriented, web-based applications. The suite uses well known design patterns and includes a fast Application Server, Servlets, Python Server Pages (PSP), Object-Relational Mapping, Task Scheduling, Session Management, and many other features. Webware is very modular and easily extended. Webware for Python is well proven and platform-independent. It is compatible with multiple web servers, database servers and operating systems. Check out the Webware for Python home page at http://www.w4py.org -- http://mail.python.org/mailman/listinfo/python-announce-list Support the Python Software Foundation: http://www.python.org/psf/donations.html
progress.py 1.0.0 - Track and display progress, providing estimated completion time.
I couldn't find any module that would just let me add progress to all the random little scripts I write. So I wrote one. You can download and read about it at http://www.casualhacker.net/blog/progress_py/ Below is the module's description. I welcome any comments and suggestions. Tim DESCRIPTION This module provides 2 classes to simply add progress display to any application. Programs with more complex GUIs might still want to use it for the estimates of time remaining it provides. Use the ProgressDisplay class if your work is done in a simple loop: from progress import * for i in ProgressDisplay(range(500)): do_work() If do_work() doesn't send any output to stdout you can use the following, which will cause a single status line to be printed and updated: from progress import * for i in ProgressDisplay(range(500), display=SINGLE_LINE): do_work() For more complex applications, you will probably need to manage a Progress object yourself: from progress import * progress = Progress(task_size) for part in task: do_work() progress.increment() progress.print_status_line() If you have a more sophisticated GUI going on, you can still use Progress objects to give you a good estimate of time remaining: from progress import * progress = Progress(task_size) for part in task: do_work() progress.increment() update_gui(progress.percentage(), progress.time_remaining()) -- Tim Newsome nuisance.at.casualhacker.net http://www.casualhacker.net/ -- http://mail.python.org/mailman/listinfo/python-announce-list Support the Python Software Foundation: http://www.python.org/psf/donations.html
Re: #! to two different pythons?
m...@pixar.com wrote: Benjamin Peterson benja...@python.org wrote: #!/usr/bin/env python But how can I handle this with two differently named pythons? #!/usr/anim/menv/bin/pypix #!/Users/mh/py/bin/python Thanks! Mark If you install using with a setup.py that uses distutils then one of the features is that any script whose first line begins '#!' and contains 'python' has that first line replaced by the current interpreter. So in this example if you install your code with: /usr/anim/menv/bin/pypix setup.py install #!/usr/bin/env python would be replaced by your desired #!/usr/anim/menv/bin/pypix. Of course for your current purposes using setup.py might be overkill. -- http://mail.python.org/mailman/listinfo/python-list
Properties for several keywords
I've to write properties for several keywords with the same code, it only changes the name of each property: - @property def foo(self): return self._foo @foo.setter def foo(self, txt): self._foo = self._any_function(txt) # @property def bar(self): return self._bar @bar.setter def bar(self, txt): self._bar = self._any_function(txt) - Is possible to simplify it? -- http://mail.python.org/mailman/listinfo/python-list
Re: Properties for several keywords
On 7 jun, 11:45, Kless jonas@googlemail.com wrote: I've to write properties for several keywords with the same code, it only changes the name of each property: - @property def foo(self): return self._foo @foo.setter def foo(self, txt): self._foo = self._any_function(txt) # @property def bar(self): return self._bar @bar.setter def bar(self, txt): self._bar = self._any_function(txt) - Is possible to simplify it? Sorry for indent the decorator. -- http://mail.python.org/mailman/listinfo/python-list
Re: Making the case for repeat
pataphor: The problem is posting *this* function would kill my earlier repeat for sure. And it already had a problem with parameters 0 (Hint: that last bug has now become a feature in the unpostable repeat implementation) Be bold, kill your precedent ideas, and post the Unpostable :-) Despite people here complaining a bit, you can't hurt posting some lines of safe code here :-) But I agree with Steven D'Aprano, adding some explaining words to your proposals helps. Bye, bearophile -- http://mail.python.org/mailman/listinfo/python-list
Re: Is reduce() foldl() or foldr()?
Steven D'Aprano st...@remove-this-cybersource.com.au writes: Calling all functional programming fans... is Python's built-in reduce() a left-fold or a right-fold? I get: reduce(lambda a, b: a/b, [1.0, 2.0, 3.0]) 0.1 which looks like a left fold to me. Tim. -- http://mail.python.org/mailman/listinfo/python-list
Re: Is reduce() foldl() or foldr()?
Steven D'Aprano wrote: Calling all functional programming fans... is Python's built-in reduce() a left-fold or a right-fold? Wikipedia says it's a left-fold: http://en.wikipedia.org/wiki/Fold_(higher-order_function) Wikipedia is correct: from __future__ import division (1/(2/(3/(4/5 # right 1.875 1/2)/3)/4)/5) # left 0.0083332 reduce(lambda x, y: x/y, range(1, 6)) 0.0083332 but other people say it's a right-fold, e.g.: ... there is a `foldr` in Haskell that just works like `reduce()` http://mail.python.org/pipermail/python-list/2007-November/638647.html and Note that Python already has a variation of foldr, called reduce. http://blog.sigfpe.com/2008/02/purely-functional-recursive-types-in.html The explicit foldr() function given in this blog agrees with Wikipedia's definition: def foldr(a, b, l): ... if l == []: ... return b ... else: ... return a(l[0], foldr(a, b, l[1:])) ... foldr(lambda x, y: x/y, 5, range(1, 5)) 1.875 Peter -- http://mail.python.org/mailman/listinfo/python-list
Re: Is reduce() foldl() or foldr()?
Steven D'Aprano wrote: Calling all functional programming fans... is Python's built-in reduce() a left-fold or a right-fold? ... So which is correct? Or is it that different people have different definitions of foldl() and foldr()? Just test. Floating point addition is not associative, so: a = reduce(float.__add__, (4095 * 2. **n for n in range(100))) b = reduce(float.__add__,(4095*2.**n for n in reversed(range(100 a - b 5.7646075230342349e+17 So, since a b, it must be foldl (the first addition happens to the first of the list). Foldl is the eager-beaver's dream; foldr is the procrastinator's dream. --Scott David Daniels scott.dani...@acm.org -- http://mail.python.org/mailman/listinfo/python-list
Keeping console window open
Hello, I need to write a simple utility program that will be used under
Windows. I want to write the utility in python and it will be run by
double-clicking the the .py-file.
I put a raw_input('Press enter to exit) at the end so the console window
wouldn't just disappear when the program is finished.
Anyway, I wrote a few lines of code and when I first tried to run it by
double-clicking the .py-file the console window still disappeared right
away. So, in order to see what was happening, I ran it from a shell and
it turned out to be a missing import. My question is how can I trap
errors encountered by the interpreter (if that is the right way to put
it) in order to keep the console window open so one has a chance to see
the error message?
- Fencer
--
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how to transfer my utf8 code saved in a file to gbk code
My file contains such strings : \xe6\x97\xa5\xe6\x9c\x9f\xef\xbc\x9a I want to read the content of this file and transfer it to the corresponding gbk code,a kind of Chinese character encode style. Everytime I was trying to transfer, it will output the same thing no matter which method was used. It seems like that when Python reads it, Python will taks '\' as a common char and this string at last will be represented as \\xe6\\x97\ \xa5\\xe6\\x9c\\x9f\\xef\\xbc\\x9a , then the \ can be 'correctly' output,but that's not what I want to get. Anyone can help me? Thanks in advance. -- http://mail.python.org/mailman/listinfo/python-list
Re: Keeping console window open
On 7 Cze, 14:49, Fencer no.i.d...@want.mail.from.spammers.com wrote: My question is how can I trap errors encountered by the interpreter (if that is the right way to put it) in order to keep the console window open so one has a chance to see the error message? Interpreter errors are same beasts as exceptions, so you can try:...except: them. -- Tomasz Zieliński http://pyconsultant.eu -- http://mail.python.org/mailman/listinfo/python-list
Re: Keeping console window open
2009/6/7 Fencer no.i.d...@want.mail.from.spammers.com Anyway, I wrote a few lines of code and when I first tried to run it by double-clicking the .py-file the console window still disappeared right away. So, in order to see what was happening, I ran it from a shell and it turned out to be a missing import. My question is how can I trap errors encountered by the interpreter (if that is the right way to put it) in order to keep the console window open so one has a chance to see the error message? I don't think this (force a console window to be kept openning only for debug purpose) is a good idea. If you just write some lines to learn something, you may run your script in a console window or in an IDE. If you are writing a big project, you'd better catch those exception and store logs in some files. However, if you still need force a console window be kept openning after the script end, you may use module atexit. -- XUE Can -- http://mail.python.org/mailman/listinfo/python-list
Re: pylint naming conventions?
Ben Finney wrote: Esmail ebo...@hotmail.com writes: I am confused by pylint's naming conventions, I don't think the are in tune with Python's style recommendations (PEP 8?) Anyone else think this? It's hard to know, without examples. Can you give some output of pylint that you think doesn't agree with PEP 8? Sure, I will next time I have a nice self-contained example. Perhaps not that many people are using pylint? I was expecting a bunch of messages either contradicting my observation or agreeing with it :-) .. but perhaps this indicates that there's no issue. I'll try to come up with a nice short code example in the next few days to demonstrate what I think the problem is and post it, thanks for the suggestion. Esmail -- http://mail.python.org/mailman/listinfo/python-list
Re: Keeping console window open
Tomasz Zieliński wrote:
On 7 Cze, 14:49, Fencer no.i.d...@want.mail.from.spammers.com wrote:
My question is how can I trap
errors encountered by the interpreter (if that is the right way to put
it) in order to keep the console window open so one has a chance to see
the error message?
Interpreter errors are same beasts as exceptions,
so you can try:...except: them.
To be a trifle more explicit, turn:
...
if __name__ == '__main__':
main()
into:
...
if __name__ == '__main__':
try:
main()
except Exception, why:
print 'Failed:', why
import sys, traceback
traceback.print_tb(sys.exc_info()[2])
raw_input('Leaving: ')
Note that building your script like this also allows you to
open the interpretter, and type:
import mymodule
mymodule.main()
in order to examine how it runs.
--Scott David Daniels
scott.dani...@acm.org
--
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The pysync library - Looking for the code, but all download links are broken
Hi, From the description the library pysync seems to be a perfect match for some of the things I would like to accomplish in my own project. The problem is that all the download links seems to be broken, so I cannot download the code. http://freshmeat.net/projects/pysync/ I've also tried to mail the author, but the mail bounces. Is there anyone out there who happens to have a tarball of this library and who could send me a copy I would be very grateful. Cheers //Jan Persson -- http://mail.python.org/mailman/listinfo/python-list
Re: Keeping console window open
Scott David Daniels wrote:
To be a trifle more explicit, turn:
...
if __name__ == '__main__':
main()
into:
...
if __name__ == '__main__':
try:
main()
except Exception, why:
print 'Failed:', why
import sys, traceback
traceback.print_tb(sys.exc_info()[2])
raw_input('Leaving: ')
Note that building your script like this also allows you to
open the interpretter, and type:
import mymodule
mymodule.main()
in order to examine how it runs.
Thanks alot, this was exactly what I was looking for!
--Scott David Daniels
scott.dani...@acm.org
--
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how to transfer my utf8 code saved in a file to gbk code
higer higerinbeij...@gmail.com wrote: My file contains such strings : \xe6\x97\xa5\xe6\x9c\x9f\xef\xbc\x9a If those bytes are what is in the file (and it sounds like they are), then the data in your file is not in UTF8 encoding, it is in ASCII encoded as hexidecimal escape codes. I want to read the content of this file and transfer it to the corresponding gbk code,a kind of Chinese character encode style. You'll have to convert it from hex-escape into UTF8 first, then. Perhaps better would be to write the original input files in UTF8, since it sounds like that is what you were intending to do. -- R. David Murray http://www.bitdance.com IT ConsultingSystem AdministrationPython Programming -- http://mail.python.org/mailman/listinfo/python-list
Re: multi-core software
On Jun 7, 1:56 am, Paul Rubin http://phr...@nospam.invalid wrote:
Jeff M. mass...@gmail.com writes:
Even the lightest weight
user space (green) threads need a few hundred instructions, minimum,
to amortize the cost of context switching
There's always a context switch. It's just whether or not you are
switching in/out a virtual stack and registers for the context or the
hardware stack/registers.
I don't see the hundreds of instructions in that case.
http://shootout.alioth.debian.org/u32q/benchmark.php?test=threadring;...
shows GHC doing 50 million lightweight thread switches in 8.47
seconds, passing a token around a thread ring. Almost all of that is
probably spent acquiring and releasing the token's lock as the token
is passed from one thread to another. That simply doesn't leave time
for hundreds of instructions per switch.
Who said there has to be? Sample code below (just to get the point
across):
struct context {
vir_reg pc, sp, bp, ... ;
object* stack;
// ...
context* next;
};
struct vm {
context* active_context;
};
void switch_context(vm* v)
{
// maybe GC v-active_context before switching
v-active_context = v-active_context-next;
}
Also, there isn't hundreds of instructions with multiplexing,
either. It's all done in hardware. Take a look at the disassembly for
any application: one that uses native threads on a platform that
supports preemption. You won't see any instructions anywhere in the
program that perform a context switch. If you did that would be
absolutely horrible. Imagine if the compiler did something like this:
while(1)
{
// whatever
}
do_context_switch_here();
That would suck. ;-)
That's not to imply that there isn't a cost; there's always a cost.
The example above just goes to show that for green threads, the cost
[of the switch] can be reduced down to a single pointer assignment.
Jeff M.
--
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Re: Is reduce() foldl() or foldr()?
Tim Northover t.p.northo...@sms.ed.ac.uk (TN) escribió: TN Steven D'Aprano st...@remove-this-cybersource.com.au writes: Calling all functional programming fans... is Python's built-in reduce() a left-fold or a right-fold? TN I get: reduce(lambda a, b: a/b, [1.0, 2.0, 3.0]) TN 0.1 TN which looks like a left fold to me. Yes, see the Haskell result: Prelude foldl (/) 1.0 [1.0, 2.0, 3.0] 0.1 Prelude foldr (/) 1.0 [1.0, 2.0, 3.0] 1.5 -- Piet van Oostrum p...@cs.uu.nl URL: http://pietvanoostrum.com [PGP 8DAE142BE17999C4] Private email: p...@vanoostrum.org -- http://mail.python.org/mailman/listinfo/python-list
Re: multi-core software
Roedy Green wrote: On Fri, 5 Jun 2009 18:15:00 + (UTC), Kaz Kylheku kkylh...@gmail.com wrote, quoted or indirectly quoted someone who said : Even for problems where it appears trivial, there can be hidden issues, like false cache coherency communication where no actual sharing is taking place. Or locks that appear to have low contention and negligible performance impact on ``only'' 8 processors suddenly turn into bottlenecks. Then there is NUMA. A given address in memory may be RAM attached to the processor accessing it, or to another processor, with very different access costs. Could what you are saying be summed up by saying, The more threads you have the more important it is to keep your threads independent, sharing as little data as possible. I see no problem with mutable shared state. -- Dr Jon D Harrop, Flying Frog Consultancy Ltd. http://www.ffconsultancy.com/?u -- http://mail.python.org/mailman/listinfo/python-list
Re: multi-core software
George Neuner wrote: On Fri, 05 Jun 2009 16:26:37 -0700, Roedy Green see_webs...@mindprod.com.invalid wrote: On Fri, 5 Jun 2009 18:15:00 + (UTC), Kaz Kylheku kkylh...@gmail.com wrote, quoted or indirectly quoted someone who said : Even for problems where it appears trivial, there can be hidden issues, like false cache coherency communication where no actual sharing is taking place. Or locks that appear to have low contention and negligible performance impact on ``only'' 8 processors suddenly turn into bottlenecks. Then there is NUMA. A given address in memory may be RAM attached to the processor accessing it, or to another processor, with very different access costs. Could what you are saying be summed up by saying, The more threads you have the more important it is to keep your threads independent, sharing as little data as possible. And therein lies the problem of leveraging many cores. There is a lot of potential parallelism in programs (even in Java :) that is lost because it is too fine a grain for threads. That will always be true so it conveys no useful information to the practitioner. Even the lightest weight user space (green) threads need a few hundred instructions, minimum, to amortize the cost of context switching. Work items in Cilk are much faster than that. Add to that the fact that programmers have shown themselves, on average, to be remarkably bad at figuring out what _should_ be done in parallel - as opposed to what _can_ be done - and you've got a clear indicator that threads, as we know them, are not scalable except under a limited set of conditions. Parallelism is inherently not scalable. I see no merit in speculating about the ramifications of average programmers alleged inabilities. -- Dr Jon D Harrop, Flying Frog Consultancy Ltd. http://www.ffconsultancy.com/?u -- http://mail.python.org/mailman/listinfo/python-list
Re: multi-core software
Scott David Daniels wrote: the nub of the problem is not on the benchmarks. There is something to be said for the good old daays when you looked up the instruction timings that you used in a little document for your machine, and could know the cost of any loop. We are faster now, but part of the cost of that speed is that timing is a black art. Those good old days never existed. Those manuals never accounted for things that affected timing even then, like memory latency or refresh time. SRAM cache made things worse, since the published timings never mentioned cache-miss delays. Though memory cache might seem a recent innovation, it's been around a while. It would be challenging to find any published timing since the commercialization of computers that would actually tell the cost of any loop. Things got worse when chips like the '86 family acquired multiple instructions for doing loops, still worse when pre-fetch pipelines became deeper and wider, absolutely Dark Art due to multi-level memory caches becoming universal, and throw-your-hands-up-and-leave-for-the-corner-bar with multiprocessor NUMA systems. OSes and high-level languages complicate the matter - you never know how much time slice you'll get or how your source got compiled or optimized by run-time. So the good old days are a matter of degree and self-deception - it was easier to fool ourselves then that we could at least guess timings proportionately if not absolutely, but things definitely get more unpredictable over evolution. -- Lew -- http://mail.python.org/mailman/listinfo/python-list
Re: how to transfer my utf8 code saved in a file to gbk code
On Jun 7, 10:55 pm, higer higerinbeij...@gmail.com wrote:
My file contains such strings :
\xe6\x97\xa5\xe6\x9c\x9f\xef\xbc\x9a
Are you sure? Does that occupy 9 bytes in your file or 36 bytes?
I want to read the content of this file and transfer it to the
corresponding gbk code,a kind of Chinese character encode style.
Everytime I was trying to transfer, it will output the same thing no
matter which method was used.
It seems like that when Python reads it, Python will taks '\' as a
common char and this string at last will be represented as \\xe6\\x97\
\xa5\\xe6\\x9c\\x9f\\xef\\xbc\\x9a , then the \ can be 'correctly'
output,but that's not what I want to get.
Anyone can help me?
try this:
utf8_data = your_data.decode('string-escape')
unicode_data = utf8_data.decode('utf8')
# unicode derived from your sample looks like this 日期： is that what
you expected?
gbk_data = unicode_data.encode('gbk')
If that doesn't work, do three things:
(1) give us some unambiguous hard evidence about the contents of your
data:
e.g. # assuming Python 2.x
your_data = open('your_file.txt', 'rb').read(36)
print repr(your_data)
print len(your_data)
print your_data.count('\\')
print your_data.count('x')
(2) show us the source of the script that you used
(3) Tell us what doesn't work means in this case
Cheers,
John
--
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Re: multi-core software
Jon Harrop wrote: Roedy Green wrote: On Fri, 5 Jun 2009 18:15:00 + (UTC), Kaz Kylheku kkylh...@gmail.com wrote, quoted or indirectly quoted someone who said : Even for problems where it appears trivial, there can be hidden issues, like false cache coherency communication where no actual sharing is taking place. Or locks that appear to have low contention and negligible performance impact on ``only'' 8 processors suddenly turn into bottlenecks. Then there is NUMA. A given address in memory may be RAM attached to the processor accessing it, or to another processor, with very different access costs. Could what you are saying be summed up by saying, The more threads you have the more important it is to keep your threads independent, sharing as little data as possible. I see no problem with mutable shared state. In which case, Jon, you're in a small minority. AHS -- http://mail.python.org/mailman/listinfo/python-list
Re: unladen swallow: python and llvm
On 5 jun, 06:29, Nick Craig-Wood n...@craig-wood.com wrote: Luis M González luis...@gmail.com wrote: I am very excited by this project (as well as by pypy) and I read all their plan, which looks quite practical and impressive. But I must confess that I can't understand why LLVM is so great for python and why it will make a difference. CPython uses a C compiler to compile the python code (written in C) into native machine code. unladen-swallow uses an llvm-specific C compiler to compile the CPython code (written in C) into LLVM opcodes. The LLVM virtual machine executes those LLVM opcodes. The LLVM virtual machine also has a JIT (just in time compiler) which converts the LLVM op-codes into native machine code. So both CPython and unladen-swallow compile C code into native machine code in different ways. So why use LLVM? This enables unladen swallow to modify the python virtual machine to target LLVM instead of the python vm opcodes. These can then be run using the LLVM JIT as native machine code and hence run all python code much faster. The unladen swallow team have a lot more ideas for optimisations, but this seems to be the main one. It is an interesting idea for a number of reasons, the main one as far as I'm concerned is that it is more of a port of CPython to a new architecture than a complete re-invention of python (like PyPy / IronPython / jython) so stands a chance of being merged back into CPython. -- Nick Craig-Wood n...@craig-wood.com --http://www.craig-wood.com/nick Thanks Nick, ok, let me see if I got it: The Python vm is written in c, and generates its own bitecodes which in turn get translated to machine code (one at a time). Unladen Swallow aims to replace this vm by one compiled with the llvm compiler, which I guess will generate different bytecodes, and in addition, supplies a jit for free. Is that correct? It's confussing to think about a compiler which is also a virtual machine, which also has a jit... Another thing that I don't understand is about the upfront compilation. Actually, the project plan doesn't mention it, but I read a comment on pypy's blog about a pycon presentation, where they said it would be upfront compilation (?). What does it mean? I guess it has nothing to do with the v8 strategy, because unladen swallow will be a virtual machine, while v8 compiles everything to machine code on the first run. But I still wonder what this mean and how this is different. By the way, I already posted a couple of question on unladen's site. But now I see the discussion is way to low level for me, and I wouldn't want to interrupt with my silly basic questions... Luis -- http://mail.python.org/mailman/listinfo/python-list
pyc-files contains absolute paths, is this a bug ?
hello, AFAIK I read that pyc files can be transferred to other systems. I finally got a windows executable working through py2exe, but still have some troubles, moving the directory around. I use Python 2.5.2. I use py2exe to make a distro I can unpack the distro, on a clean computer, anywhere where I like, and it runs fine. Now when I've run it once, I move the subdirectory to another location, at it doesn't run. Looking with a hex editor into some pyc-files, I see absolute paths to the old directory. Is this normal, or am I doing something completely wrong ? thanks, Stef Mientki -- http://mail.python.org/mailman/listinfo/python-list
Python preprosessor
I am developing a Python application as a Python2.x and Python3.0
version. A common code base would make the work easier. So I thought to
try a preprosessor. GNU cpp handles this kind of code correct:
test_cpp.py
#ifdef python2
print u'foo', u'bar'
#endif
#ifdef python3
print('foo', 'bar')
#endif
end code
results:
cpp -E -Dpython2 test_cpp.py
...
print u'foo', u'bar'
Any other suggestions?
Tuomas Vesterinen
--
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Re: Iterating Over Dictionary From Arbitrary Location
In article mailman.1241.1244301490.8015.python-l...@python.org, akindo akind...@hotmail.com wrote: So, it seems I want the best of both worlds: specific indexing using my own IDs/keys (not just by list element location), sorting and the ability to start iterating from a specific location. I am trying to prevent having to scan through a list from the beginning to find the desired ID, and then return all elements after that. Is there another data structure or design pattern which will do what I want? Thanks a lot for any help! :) One option is to maintain both a dict and a list; it doesn't cost much memory because the individual elements don't get copied. See various ordered dictionary implementations for ideas on coding this. -- Aahz (a...@pythoncraft.com) * http://www.pythoncraft.com/ If you don't know what your program is supposed to do, you'd better not start writing it. --Dijkstra -- http://mail.python.org/mailman/listinfo/python-list
Re: Python preprosessor
Tuomas Vesterinen wrote: I am developing a Python application as a Python2.x and Python3.0 version. A common code base would make the work easier. So I thought to try a preprosessor. GNU cpp handles this kind of code correct: Any other suggestions? http://docs.python.org/dev/3.1/library/2to3.html -- http://mail.python.org/mailman/listinfo/python-list
Re: pyc-files contains absolute paths, is this a bug ?
On Sun, 07 Jun 2009 18:16:26 +0200, Stef Mientki wrote: hello, AFAIK I read that pyc files can be transferred to other systems. I finally got a windows executable working through py2exe, but still have some troubles, moving the directory around. Sounds like a py2exe problem, not a Python problem. Perhaps you should ask them? https://lists.sourceforge.net/lists/listinfo/py2exe-users I use Python 2.5.2. I use py2exe to make a distro I can unpack the distro, on a clean computer, anywhere where I like, and it runs fine. Now when I've run it once, I move the subdirectory to another location, at it doesn't run. Define doesn't run. You mean the exe file doesn't launch at all? Does Windows display an error message? Or perhaps it launches, then immediately exists? Launches, then crashes? Does it show up in the process list at all? Or something else? -- Steven -- http://mail.python.org/mailman/listinfo/python-list
Re: Is reduce() foldl() or foldr()?
Steven D'Aprano st...@remove-this-cybersource.com.au writes: Calling all functional programming fans... is Python's built-in reduce() a left-fold or a right-fold? It's a left fold. but other people say it's a right-fold, e.g.: ... there is a `foldr` in Haskell that just works like `reduce()` That is correct in the sense that a coding situation where you'd use reduce in Python would often lead you to use foldr (with its different semantics) in Haskell. This is because of Haskell's lazy evaluation. Example: suppose you have a list of lists, like xss = [[1,2],[3,4,5],[6,7]] and you want to concatenate them all. (++) is Haskell's list concatenation function, like Python uses + for list concatenation. So you could say ys = foldl (++) [] xss but if I have it right, that would have to traverse the entire input list before it gives you any of the answer, which can be expensive for a long list, or fail totally for an infinite list. foldr on the other hand can generate the result lazily, in sync with the way the caller consumes the elements, like writing a generator in Haskell. The tutorial http://learnyouahaskell.com/higher-order-functions#folds explains this a bit more. You might also like the Real World Haskell book: http://book.realworldhaskell.org -- http://mail.python.org/mailman/listinfo/python-list
Re: unladen swallow: python and llvm
Neuruss wrote: On 5 jun, 06:29, Nick Craig-Wood n...@craig-wood.com wrote: Luis M González luis...@gmail.com wrote: I am very excited by this project (as well as by pypy) and I read all their plan, which looks quite practical and impressive. But I must confess that I can't understand why LLVM is so great for python and why it will make a difference. CPython uses a C compiler to compile the python code (written in C) into native machine code. unladen-swallow uses an llvm-specific C compiler to compile the CPython code (written in C) into LLVM opcodes. The LLVM virtual machine executes those LLVM opcodes. The LLVM virtual machine also has a JIT (just in time compiler) which converts the LLVM op-codes into native machine code. So both CPython and unladen-swallow compile C code into native machine code in different ways. So why use LLVM? This enables unladen swallow to modify the python virtual machine to target LLVM instead of the python vm opcodes. These can then be run using the LLVM JIT as native machine code and hence run all python code much faster. The unladen swallow team have a lot more ideas for optimisations, but this seems to be the main one. It is an interesting idea for a number of reasons, the main one as far as I'm concerned is that it is more of a port of CPython to a new architecture than a complete re-invention of python (like PyPy / IronPython / jython) so stands a chance of being merged back into CPython. -- Nick Craig-Wood n...@craig-wood.com --http://www.craig-wood.com/nick Thanks Nick, ok, let me see if I got it: The Python vm is written in c, and generates its own bitecodes which in turn get translated to machine code (one at a time). Unladen Swallow aims to replace this vm by one compiled with the llvm compiler, which I guess will generate different bytecodes, and in addition, supplies a jit for free. Is that correct? [snip] No. CPython is written in C (hence the name). It compiles Python source code to bytecodes. The bytecodes are instructions for a VM which is written in C, and they are interpreted one by one. There's no compilation to machine code. -- http://mail.python.org/mailman/listinfo/python-list
Re: Python preprosessor
Peter Otten wrote: Tuomas Vesterinen wrote: I am developing a Python application as a Python2.x and Python3.0 version. A common code base would make the work easier. So I thought to try a preprosessor. GNU cpp handles this kind of code correct: Any other suggestions? http://docs.python.org/dev/3.1/library/2to3.html I am intensively using 2to3.py. So I have 2 codebase: one in py2 and the other in py3. When changing the code I have to do things to 2 separate codebase in the repository. There are no patch2to3 or patch3to2, So I thought that for ensuring the common functionality of both version it would be nice to bring both versions into a common codebase. So I can update only one code and automate builds and tests for both versions. Tuomas Vesterinen -- http://mail.python.org/mailman/listinfo/python-list
Re: unladen swallow: python and llvm
Neuruss luis...@gmail.com wrote: ok, let me see if I got it: The Python vm is written in c, and generates its own bitecodes which in turn get translated to machine code (one at a time). Unladen Swallow aims to replace this vm by one compiled with the llvm compiler, which I guess will generate different bytecodes, and in addition, supplies a jit for free. Is that correct? Pretty good I think! It's confussing to think about a compiler which is also a virtual machine, which also has a jit... Well the compiler is actually gcc with a llvm opcodes backend. Another thing that I don't understand is about the upfront compilation. Actually, the project plan doesn't mention it, but I read a comment on pypy's blog about a pycon presentation, where they said it would be upfront compilation (?). What does it mean? I don't know, I'm afraid. I guess it has nothing to do with the v8 strategy, because unladen swallow will be a virtual machine, while v8 compiles everything to machine code on the first run. But I still wonder what this mean and how this is different. -- Nick Craig-Wood n...@craig-wood.com -- http://www.craig-wood.com/nick -- http://mail.python.org/mailman/listinfo/python-list
Re: multi-core software
Arved Sandstrom wrote: Jon Harrop wrote: I see no problem with mutable shared state. In which case, Jon, you're in a small minority. No. Most programmers still care about performance and performance means mutable state. -- Dr Jon D Harrop, Flying Frog Consultancy Ltd. http://www.ffconsultancy.com/?u -- http://mail.python.org/mailman/listinfo/python-list
Re: multi-core software
Jon Harrop wrote: No. Most programmers still care about performance and performance means mutable state. [ Citation needed ]. Most programmers I've met could care less about performance. -- Beware of bugs in the above code; I have only proved it correct, not tried it. -- Donald E. Knuth -- http://mail.python.org/mailman/listinfo/python-list
Re: unladen swallow: python and llvm
Luis M. González: it seems they intend to do upfront compilation. How? Unladen swallow developers want to try everything (but black magic and necromancy) to increase the speed of Cpython. So they will try to compile up-front if/where they can (for example most regular expressions are known at compile time, so there's no need to compile them at run time. I don't know if Cpython compiles them before running time). What I like of Unladen swallow is that it's a very practical approach, very different in style from ShedSkin and PyPy (and it's more ambitious than Psyco). I also like Unladen swallow because they are the few people that have the boldness to do something to increase the performance of Python for real. They have a set of reference benchmarks that are very real, not synthetic at all, so for example they refuse to use Pystones and the like. What I don't like of Unladen swallow is that integrating LLVM with the CPython codebase looks like a not much probable thing. Another thing I don't like is the name of such project, it's not easy to pronounce for non-English speaking people. Bye, bearophile -- http://mail.python.org/mailman/listinfo/python-list
Re: Get the class name
Kless wrote: Is there any way of to get the class name to avoid to have that write it? --- class Foo: super(Foo, self) --- * Using Py 2.6.2 class Foo(object): ... def cls(self): ... return self.__class__ ... Foo().cls() class '__main__.Foo' -- http://mail.python.org/mailman/listinfo/python-list
pypi compatible software
i've been searching for a recommended way to setup private pypi repository and i've found several options: - PloneSoftwareCenter - http://code.google.com/p/pypione/ - http://pypi.python.org/pypi/haufe.eggserver - http://www.chrisarndt.de/projects/eggbasket/ - http://pypi.python.org/pypi/ClueReleaseManager so now i have a few questions: - is code behind pypi.python.org available and why i can't find some up-to-date official document or howto for private pypi repository (maybe it exists but i just can't find it)? - since python is used in commercial environments i guess they actually have private pypi repositories, where can i find docs that defines what pypi is and how to implement it? - can you recommend 1 option (software providing pypi like service) that can be easily installed and configured as a service running on apache2/mod_wsgi, has an active community and docs howto setup? - i did found http://www.python.org/dev/peps/pep-0381/ - is this the spec that above mentioned software is based upon? any additional info or comments appreciated. Aljosa Mohorovic -- http://mail.python.org/mailman/listinfo/python-list
Re: multi-core software
Jon Harrop wrote: Arved Sandstrom wrote: Jon Harrop wrote: I see no problem with mutable shared state. In which case, Jon, you're in a small minority. No. Most programmers still care about performance and performance means mutable state. I don't see why that would affect whether one thinks there are problems. In my opinion, shared mutable state has a lot of problems. It is also sometimes the best design for performance reasons. Patricia -- http://mail.python.org/mailman/listinfo/python-list
Re: The pysync library - Looking for the code, but all download links are broken
I think what you are looking for can be found at: http://www.google.com/codesearch/p?hl=en#RncWxgazS6A/pysync-2.24/test/testdata.pyq=pysync%20package:%22http://minkirri.apana.org.au/~abo/projects/pysync/arc/pysync-2.24.tar.bz2%22%20lang:python or http://shortlink.dk/58664133 I am not affiliated with the project in any way, and I can't find a way to download the entire thing in one go. So if you do salvage a working copy please let me (and the rest of the community) know. //Søren - Peng - Pedersen -- http://mail.python.org/mailman/listinfo/python-list
Re: multi-core software
Arved Sandstrom wrote: Jon Harrop wrote: Arved Sandstrom wrote: Jon Harrop wrote: I see no problem with mutable shared state. In which case, Jon, you're in a small minority. No. Most programmers still care about performance and performance means mutable state. Quite apart from performance and mutable state, I believe we were talking about mutable _shared_ state. And this is something that gets a _lot_ of people into trouble. Nonsense. Scientists have been writing parallel programs for decades using shared state extensively without whining about it. Databases are mutable shared state but millions of database programmers solve real problems every day without whining about it. Use your common sense and you can write efficient parallel programs today with little difficulty. I do. -- Dr Jon D Harrop, Flying Frog Consultancy Ltd. http://www.ffconsultancy.com/?u -- http://mail.python.org/mailman/listinfo/python-list
Re: multi-core software
Joshua Cranmer wrote: Jon Harrop wrote: No. Most programmers still care about performance and performance means mutable state. [ Citation needed ]. Most programmers I've met could care less about performance. Then they have no need for parallelism in the first place. -- Dr Jon D Harrop, Flying Frog Consultancy Ltd. http://www.ffconsultancy.com/?u -- http://mail.python.org/mailman/listinfo/python-list
Re: Properties for several keywords
On 7 jun, 11:45, Kless jonas@googlemail.com wrote: I've to write properties for several keywords with the same code, it only changes the name of each property: - @property def foo(self): return self._foo @foo.setter def foo(self, txt): self._foo = self._any_function(txt) # @property def bar(self): return self._bar @bar.setter def bar(self, txt): self._bar = self._any_function(txt) - Is possible to simplify it? Please, is there any solution for this problem? -- http://mail.python.org/mailman/listinfo/python-list
Re: How to get local copy of docs?
In eff6307d-e3d5-4b26-ac7c-a658f1b96...@z7g2000vbh.googlegroups.com TonyM foss...@gmail.com writes: http://docs.python.org/download.html Perfect. Thanks! kynn -- -- http://mail.python.org/mailman/listinfo/python-list
Re: unladen swallow: python and llvm
bearophileh...@lycos.com writes: What I like of Unladen swallow is that it's a very practical approach, very different in style from ShedSkin and PyPy (and it's more ambitious than Psyco). I also like Unladen swallow because they are the few people that have the boldness to do something to increase the performance of Python for real. IMHO the main problem with the Unladen Swallow approach is that it would surprise me if CPython really spends that much of its time interpreting byte code. Is there some profiling output around? My guess is that CPython spends an awful lot of time in dictionary lookups for method calls, plus incrementing and decrementing ref counts and stuff like that. Plus, the absence of a relocating garbage collector may mess up cache hit ratios pretty badly. Shed Skin as I understand it departs in some ways from Python semantics in order to get better compiler output, at the expense of breaking some Python programs. I think that is the right approach, as long as it's not done too often. That's the main reason why I think it's unfortunate that Python 3.0 broke backwards compatibility at the particular time that it did. -- http://mail.python.org/mailman/listinfo/python-list
Re: multi-core software
On Jun 7, 3:19 pm, Arved Sandstrom dces...@hotmail.com wrote: Jon Harrop wrote: Arved Sandstrom wrote: Jon Harrop wrote: I see no problem with mutable shared state. In which case, Jon, you're in a small minority. No. Most programmers still care about performance and performance means mutable state. Quite apart from performance and mutable state, I believe we were talking about mutable _shared_ state. And this is something that gets a _lot_ of people into trouble. Mutable shared state gets _bad_ (err.. perhaps inexperienced would be a better adjective) programmers - who don't know what they are doing - in trouble. There are many problem domains that either benefit greatly from mutable shared states or can't [easily] be done without them. Unified memory management being an obvious example... there are many more. Unshared state has its place. Immutable state has its place. Shared immutable state has its place. Shared mutable place has its place. Jeff M. -- http://mail.python.org/mailman/listinfo/python-list
Re: multi-core software
Jon Harrop wrote: I see no problem with mutable shared state. In which case, Jon, you're in a small minority. Patricia Shanahan wrote: In my opinion, shared mutable state has a lot of problems. It is also sometimes the best design for performance reasons. As Dr. Jon pointed out upthread, one can write decent code with mutable shared state. It is also true that mutable state presents a lot of problems - potential problems, ones that can be solved, but not ones that can be solved thoughtlessly. On the flip side, one can write a tremendous amount of effective multi-threaded code involving shared mutable state with attention to a few rules of thumb, like always synchronize access and don't use different monitors to do so. Unlike some environments (e.g., database management systems), Java's tools to manage concurrency are explicit and low level. The programmer's job is to make sure those tools are used correctly to avoid problems. As long as they do that, then there is no special problem with shared mutable state. There is, however, a cost. Certain things must happen slower when you share mutable state, than when you share immutable state or don't share state. Certain things must happen when you share mutable state, regardless of speed, because without them your code doesn't work. For some reason, concurrent programming is an area often not well understood by a significant percentage of workaday programmers. When problems do arise, they tend to be probabilistic in nature and vary widely with system characteristics like attempted load. So the meeting ground is, yes, concurrent mutable state can present problems if not properly managed. Properly managing such is not necessarily a huge burden, but it must be borne. When done properly, shared mutable state will not present problems in production. -- Lew -- http://mail.python.org/mailman/listinfo/python-list
Re: multi-core software
Jeff M. wrote: On Jun 7, 3:19 pm, Arved Sandstrom dces...@hotmail.com wrote: Jon Harrop wrote: Arved Sandstrom wrote: Jon Harrop wrote: I see no problem with mutable shared state. In which case, Jon, you're in a small minority. No. Most programmers still care about performance and performance means mutable state. Quite apart from performance and mutable state, I believe we were talking about mutable _shared_ state. And this is something that gets a _lot_ of people into trouble. Mutable shared state gets _bad_ (err.. perhaps inexperienced would be a better adjective) programmers - who don't know what they are doing - in trouble. There are many problem domains that either benefit greatly from mutable shared states or can't [easily] be done without them. Unified memory management being an obvious example... there are many more. Unshared state has its place. Immutable state has its place. Shared immutable state has its place. Shared mutable place has its place. Exactly. I don't believe that shared mutable state is any harder to do correctly than the next solution and it is almost always the most efficient solution and the sole purpose of writing parallel programs to leverage multicores is performance. A bad developer can screw up anything. I see no reason to think that shared mutable state is any more fragile than the next thing a bad developer can screw up. -- Dr Jon D Harrop, Flying Frog Consultancy Ltd. http://www.ffconsultancy.com/?u -- http://mail.python.org/mailman/listinfo/python-list
Re: pypi compatible software
- is code behind pypi.python.org available and why i can't find some up-to-date official document or howto for private pypi repository (maybe it exists but i just can't find it)? The code is at https://svn.python.org/packages/ Instructions for installing it are at http://wiki.python.org/moin/CheeseShopDev I don't know why you can't find it, perhaps you didn't search long enough. - since python is used in commercial environments i guess they actually have private pypi repositories, where can i find docs that defines what pypi is and how to implement it? IMO, there can't possibly be a private pypi repository. By (my) definition, PyPI is *the* Python Package Index - anything else holding packages can't be *the* index. So: pypi is a short name for the machine pypi.python.org, and it is not possible to implement it elsewhere, unless you have write access to the nameserver of python.org. Maybe you are asking for a specification of how setuptools and easy_install access the index, to build package repositories other than PyPI. This is specified at http://peak.telecommunity.com/DevCenter/EasyInstall#package-index-api If you are asking for something else, please be more explicit what it is that you ask for. - can you recommend 1 option (software providing pypi like service) that can be easily installed and configured as a service running on apache2/mod_wsgi, has an active community and docs howto setup? If you want a plain package repository, I recommend to use Apache without any additional software. It's possible to provide a package repository completely out of static files - no dynamic code is necessary. - i did found http://www.python.org/dev/peps/pep-0381/ - is this the spec that above mentioned software is based upon? No, that's what the title of the document says: a Mirroring infrastructure for PyPI. Regards, Martin -- http://mail.python.org/mailman/listinfo/python-list
Re: multi-core software
Lew wrote: As Dr. Jon pointed out upthread, one can write decent code with mutable shared state. It is also true that mutable state presents a lot of problems - potential problems, ones that can be solved, but not ones that can be solved thoughtlessly. On the flip side, one can write a tremendous amount of effective multi-threaded code involving shared mutable state with attention to a few rules of thumb, like always synchronize access and don't use different monitors to do so. Unlike some environments (e.g., database management systems), Java's tools to manage concurrency are explicit and low level. The programmer's job is to make sure those tools are used correctly to avoid problems. As long as they do that, then there is no special problem with shared mutable state. There is, however, a cost. Certain things must happen slower when you share mutable state, than when you share immutable state or don't share state. Certain things must happen when you share mutable state, regardless of speed, because without them your code doesn't work. For some reason, concurrent programming is an area often not well understood by a significant percentage of workaday programmers. When problems do arise, they tend to be probabilistic in nature and vary widely with system characteristics like attempted load. So the meeting ground is, yes, concurrent mutable state can present problems if not properly managed. Properly managing such is not necessarily a huge burden, but it must be borne. When done properly, shared mutable state will not present problems in production. I agree entirely but my statements were about parallelism and not concurrency. Parallel and concurrent programming have wildly different characteristics and solutions. I don't believe shared mutable state is overly problematic in the context of parallelism. Indeed, I think it is usually the best solution in that context. -- Dr Jon D Harrop, Flying Frog Consultancy Ltd. http://www.ffconsultancy.com/?u -- http://mail.python.org/mailman/listinfo/python-list
Re: multi-core software
Jon Harrop wrote: I agree entirely but my statements were about parallelism and not concurrency. Parallel and concurrent programming have wildly different characteristics and solutions. I don't believe shared mutable state is overly problematic in the context of parallelism. Indeed, I think it is usually the best solution in that context. Interesting distinction. Would it be fair to compare concurrent programming to the bricks used to build the parallel program's edifice? -- Lew -- http://mail.python.org/mailman/listinfo/python-list
Re: Properties for several keywords
Kless wrote:
On 7 jun, 11:45, Kless jonas@googlemail.com wrote:
I've to write properties for several keywords with the same code, it
only changes the name of each property:
...
Is possible to simplify it?
Please, is there any solution for this problem?
Read up on property. It is the core of your answer. That being said,
from your recent messages, it looks a lot like you are fighting the
language, rather than using it. Pythonic code is clear about what
it is doing; avoid tricky automatic stuff.
def mangled(name, doc_text=None):
funny_name = '_' + name
def getter(self):
return getattr(self, funny_name)
def setter(self, text):
setattr(self, funny_name, self._mangle(text))
return property(getter, setter, doc=doc_text)
class MangledParts(object):
blue = mangled('blue', our side)
red = mangled('red', their side)
white = mangled('white', the poor civilians)
def _mangle(self, text):
print text
return text.join('')
--Scott David Daniels
scott.dani...@acm.org
--
http://mail.python.org/mailman/listinfo/python-list
Re: multi-core software
On Sun, 07 Jun 2009 11:16:46 -0400, Lew wrote: So the good old days are a matter of degree and self-deception - it was easier to fool ourselves then that we could at least guess timings proportionately if not absolutely, but things definitely get more unpredictable over evolution. As I recall I could get exact timings on my 6502 based Commodore 64. The issues you speak of simply weren't issues. -- Ken T. http://www.electricsenator.net Never underestimate the power of stupid people in large groups. -- http://mail.python.org/mailman/listinfo/python-list
Re: unladen swallow: python and llvm
Paul Rubin: IMHO the main problem with the Unladen Swallow approach is that it would surprise me if CPython really spends that much of its time interpreting byte code. Note that Py3 already has a way to speed up byte code interpretation where compiled by GCC or Intel compiler (it's a very old strategy used by Forth compilers, that in Py3 is used only partially. The strongest optimizations used many years ago in Forth aren't used yet in Py3, probably to keep the Py3 virtual machine simpler, or maybe because there are not enough Forth experts among them). Unladen swallow developers are smart and they attack the problem from every side they can think of, plus some sides they can't think of. Be ready for some surprises :-) Is there some profiling output around? I am sure they swim every day in profiler outputs :-) But you have to ask to them. Plus, the absence of a relocating garbage collector may mess up cache hit ratios pretty badly. I guess they will try to add a relocating GC too, of course. Plus some other strategy. And more. And then some cherries on top, with whipped cream just to be sure. Shed Skin as I understand it departs in some ways from Python semantics in order to get better compiler output, at the expense of breaking some Python programs. I think that is the right approach, as long as it's not done too often. ShedSkin (SS) is a beast almost totally different from CPython, SS compiles an implicitly static subset of Python to C++. So it breaks most real Python programs, and it doesn't use the Python std lib (it rebuilds one in C++ or compiled Python), and so on. SS may be useful for people that don't want to mess with the intricacies of Cython (ex-Pyrex) and its tricky reference count, to create compiled python extensions. But so far I think nearly no one is using SS for such purpose, so it may be a failed experiment (SS is also slow in compiling, it's hard to make it compile more than 1000-5000 lines of code). Bye, bearophile -- http://mail.python.org/mailman/listinfo/python-list
Re: unladen swallow: python and llvm
On Fri, Jun 5, 2009 at 3:29 AM, Nick Craig-Wood n...@craig-wood.com wrote: It is an interesting idea for a number of reasons, the main one as far as I'm concerned is that it is more of a port of CPython to a new architecture than a complete re-invention of python (like PyPy / IronPython / jython) so stands a chance of being merged back into CPython. Blatant fanboyism. PyPy also has a chance of being merged back into Python trunk. -- http://mail.python.org/mailman/listinfo/python-list
Re: can it be shorter?
On Jun 6, 8:07 am, tsangpo tsangpo.newsgr...@gmail.com wrote:
I want to ensure that the url ends with a '/', now I have to do thisa like
below.
url = url + '' if url[-1] == '/' else '/'
Is there a better way?
url+= { '/': '' }.get( url[ -1 ], '/' )
Shorter is always better.
--
http://mail.python.org/mailman/listinfo/python-list
Re: can it be shorter?
Since extra slashes at the end of a URL are ignored, that means I win!
url+='/'
On Sun, Jun 7, 2009 at 4:45 PM, Aaron Brady castiro...@gmail.com wrote:
On Jun 6, 8:07 am, tsangpo tsangpo.newsgr...@gmail.com wrote:
I want to ensure that the url ends with a '/', now I have to do thisa
like
below.
url = url + '' if url[-1] == '/' else '/'
Is there a better way?
url+= { '/': '' }.get( url[ -1 ], '/' )
Shorter is always better.
--
http://mail.python.org/mailman/listinfo/python-list
--
http://mail.python.org/mailman/listinfo/python-list
Re: multi-core software
Lew wrote: Jon Harrop wrote: I agree entirely but my statements were about parallelism and not concurrency. Parallel and concurrent programming have wildly different characteristics and solutions. I don't believe shared mutable state is overly problematic in the context of parallelism. Indeed, I think it is usually the best solution in that context. Interesting distinction. Would it be fair to compare concurrent programming to the bricks used to build the parallel program's edifice? Way too much of a fine distinction. While they are in fact different, the point of concurrent programming is to structure programs as a group of computations, which can be executed in parallel (however that might actually be done depending on how many processors there are). Parallel computing means to carry out many computations simultaneously. These are interleaved definitions. And they are *not* wildly different. If you talk about shared mutable state, it is not as easy to use as Dr Harrop seems to think it is. Maybe in his experience it has been, but in general it's no trivial thing to manage. Lew, you probably summarized it best a few posts upstream. AHS -- http://mail.python.org/mailman/listinfo/python-list
Re: Python preprosessor
-BEGIN PGP SIGNED MESSAGE-
Hash: SHA1
Tuomas Vesterinen wrote:
I am intensively using 2to3.py. So I have 2 codebase: one in py2 and the
other in py3.
The expectation would be that you only maintain the py2 code and
automatically generate the py3 code on demand using 2to3.
It is possible to have the same code run under both versions, but not
recommended. As an example I do this for the APSW test suite, mostly
because the test code deliberately explores various corner cases that
2to3 could not convert (nor should it try!). Here is how I do the whole
Unicode thing:
if py3: # defined earlier
UPREFIX=
else:
UPREFIX=u
def u(x): # use with raw strings
return eval(UPREFIX+'''+x+''')
# Example of use
u(r\N${BLACK STAR}\u234)
You can pull similar stunts for bytes (I use buffers in py2), long ints
(needing L suffix in some py2 versions), the next() builtin from py3,
exec syntax differences etc. You can see more details in the first 120
lines of http://code.google.com/p/apsw/source/browse/apsw/trunk/tests.py
Roger
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iEYEARECAAYFAkosTxEACgkQmOOfHg372QS4rQCgl1ymNME2kdHTBUoc7/f2e+W6
cbMAmwf7mArr7hVA8k/US53JE59ChnIt
=pQ92
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Re: Making the case for repeat
[pataphor] So here is my proposed suggestion for a once and for all reconciliation of various functions in itertools that can not stand on their own and keep a straight face. Interesting phraseology ;-) Enticing and yet fallacious in its presumption of known and accepted usability problems. FWIW, when I designed the module, I started by researching constructs that had proven success in functional languages and then adapted them to the needs of Python applications. That being said, I'm always open to hearing new ideas. After reading this thread a couple times, I have a few thoughts to offer. 1. The Pythonic Way(tm) is to avoid combining too much functionality in a single function, preferring to split when possible. That is why ifilter() and ifilterfalse() are separate functions. (FWIW, the principle is considered pythonic because it was articulated by Guido and has been widely applied throughout the language.) There is a natural inclination to do the opposite. We factor code to eliminate redundancy, but that is not always a good idea with an API. The goal for code factoring is to minimize redundancy. The goal for API design is having simple parts that are easily learned and can be readily combined (i.e. the notion of an iterator algebra). It is not progress to mush the parts together in a single function requiring multiple parameters. 2. I question the utility of some combining repeat() and cycle() because I've not previously seen the two used together. OTOH, there may be some utility to producing a fixed number of cycles (see the ncycles() recipe in the docs). Though, if I thought this need arose very often (it has never been requested), the straight-forward solution would be to add a times argument to cycle(), patterned after repeat()'s use of a times argument. 3. Looking at the sample code provided in your post, I would suggest rewriting it as a factory function using the existing tools as components. That way, the result of the function will still run at C speed and not be slowed by corner cases or unused parameters. (see the ncycles recipe for an example of how to do this). 4. The suggested combined function seems to emphasize truncated streams (i.e. a fixed number of repetitions or cycles). This is at odds with the notion of a toolset designed to allow lazy infinite iterators to be fed to consumer functions that truncate on the shortest iterable. For example, the toolset supports: izip(mydata, count(), repeat(datetime.now())) in preference to: izip(mydata, islice(count(), len(mydata)), repeat(datetime.now (),times=len(mydata))) To gain a better appreciation for this style (and for the current design of itertools), look at the classic Hughes' paper Why Functional Programming Matters. http://www.math.chalmers.se/~rjmh/Papers/whyfp.pdf Raymond -- http://mail.python.org/mailman/listinfo/python-list
Re: how to transfer my utf8 code saved in a file to gbk code
On Jun 8, 12:13 am, R. David Murray rdmur...@bitdance.com wrote: higer higerinbeij...@gmail.com wrote: My file contains such strings : \xe6\x97\xa5\xe6\x9c\x9f\xef\xbc\x9a If those bytes are what is in the file (and it sounds like they are), then the data in your file is not in UTF8 encoding, it is in ASCII encoded as hexidecimal escape codes. OK, I'll bite: what *ASCII* character is encoded as either \xe6 or r\xe6 by what mechanism in which parallel universe? -- http://mail.python.org/mailman/listinfo/python-list
Re: multi-core software
Arved Sandstrom wrote: Lew wrote: Interesting distinction. Would it be fair to compare concurrent programming to the bricks used to build the parallel program's edifice? Way too much of a fine distinction. While they are in fact different, the point of concurrent programming is to structure programs as a group of computations, which can be executed in parallel (however that might actually be done depending on how many processors there are). No. Concurrent programming is about interleaving computations in order to reduce latency. Nothing to do with parallelism. -- Dr Jon D Harrop, Flying Frog Consultancy Ltd. http://www.ffconsultancy.com/?u -- http://mail.python.org/mailman/listinfo/python-list
Re: multi-core software
Lew wrote: Jon Harrop wrote: I agree entirely but my statements were about parallelism and not concurrency. Parallel and concurrent programming have wildly different characteristics and solutions. I don't believe shared mutable state is overly problematic in the context of parallelism. Indeed, I think it is usually the best solution in that context. Interesting distinction. Would it be fair to compare concurrent programming to the bricks used to build the parallel program's edifice? Concurrent programming certainly underpins the foundations of almost all parallel programs. Not least at the level of the OS scheduling the threads than run the parallel programs. However, that knowledge is probably more confusing than helpful here. In essence, concurrent programming is concerned with reducing latency (e.g. evading blocking) by interleaving computations whereas parallel programming is concerned with maximizing throughput by performing computations at the same time. Historically, concurrency has been of general interest on single core machines in the context of operating systems and IO and has become more important recently due to the ubiquity of web programming. Parallelism was once only important to computational scientists programming shared-memory supercomputers and enterprise developers programming distributed-memory clusters but the advent of multicore machines on the desktop and in the games console has pushed parallelism into the lime light for ordinary developers when performance is important. Solutions for concurrent and parallel programming are also wildly different. Concurrent programming typically schedules work items that are expected to block on a shared queue for a pool of dozens or even hundreds of threads. Parallel programming typically schedules work items that are expected to not block on wait-free work-stealing queues for a pool of n threads where n is the number of cores. Solutions for concurrent programming (such as the .NET thread pool and asynchronous workflows in F#) can be used as a poor man's solution for parallel programming but the overheads are huge because they were not designed for this purpose so performance is much worse than necessary. Solutions for parallel programming (e.g. Cilk, the Task Parallel Library) are virtually useless for concurrent programming because you quickly end up with all n threads blocked and the whole program stalls. -- Dr Jon D Harrop, Flying Frog Consultancy Ltd. http://www.ffconsultancy.com/?u -- http://mail.python.org/mailman/listinfo/python-list
Re: how to transfer my utf8 code saved in a file to gbk code
John Machin wrote: On Jun 8, 12:13 am, R. David Murray rdmur...@bitdance.com wrote: higer higerinbeij...@gmail.com wrote: My file contains such strings : \xe6\x97\xa5\xe6\x9c\x9f\xef\xbc\x9a If those bytes are what is in the file (and it sounds like they are), then the data in your file is not in UTF8 encoding, it is in ASCII encoded as hexidecimal escape codes. OK, I'll bite: what *ASCII* character is encoded as either \xe6 or r\xe6 by what mechanism in which parallel universe? Maybe he means that the file itself is in ASCII. -- http://mail.python.org/mailman/listinfo/python-list
Re: Keeping console window open
Fencer wrote:
div class=moz-text-flowed style=font-family: -moz-fixedScott
David Daniels wrote:
To be a trifle more explicit, turn:
...
if __name__ == '__main__':
main()
into:
...
if __name__ == '__main__':
try:
main()
except Exception, why:
print 'Failed:', why
import sys, traceback
traceback.print_tb(sys.exc_info()[2])
raw_input('Leaving: ')
Note that building your script like this also allows you to
open the interpretter, and type:
import mymodule
mymodule.main()
in order to examine how it runs.
Thanks alot, this was exactly what I was looking for!
--Scott David Daniels
scott.dani...@acm.org
/div
Notice also that you'd then move all the imports inside main(), rather
than putting them at outer scope. Now some imports, such as sys and os,
may want to be at outer scope, but if they don't work,. your system is
seriously busted.
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Re: multi-core software
Jon Harrop wrote: ... Historically, concurrency has been of general interest on single core machines in the context of operating systems and IO and has become more important recently due to the ubiquity of web programming. Parallelism was once only important to computational scientists programming shared-memory supercomputers and enterprise developers programming distributed-memory clusters but the advent of multicore machines on the desktop and in the games console has pushed parallelism into the lime light for ordinary developers when performance is important. ... Parallelism has also been important, for a long time, to multiprocessor operating system developers. I got my first exposure to parallel programming, in the 1980's, working on NCR's VRX operating system. Patricia -- http://mail.python.org/mailman/listinfo/python-list
Re: how to transfer my utf8 code saved in a file to gbk code
On Jun 8, 10:20 am, MRAB pyt...@mrabarnett.plus.com wrote: John Machin wrote: On Jun 8, 12:13 am, R. David Murray rdmur...@bitdance.com wrote: higer higerinbeij...@gmail.com wrote: My file contains such strings : \xe6\x97\xa5\xe6\x9c\x9f\xef\xbc\x9a If those bytes are what is in the file (and it sounds like they are), then the data in your file is not in UTF8 encoding, it is in ASCII encoded as hexidecimal escape codes. OK, I'll bite: what *ASCII* character is encoded as either \xe6 or r\xe6 by what mechanism in which parallel universe? Maybe he means that the file itself is in ASCII. Maybe indeed, but only so because hex escape codes are by design in ASCII. in ASCII is redundant ... I can't imagine how the OP parsed ASCII omitted 'because it is' encoded given that his native tongue's grammar varies from that of English in several interesting ways :-) -- http://mail.python.org/mailman/listinfo/python-list
pythoncom and writing file summary info on Windows
Hello,
I was trying to put together a script that would write things like the
Author and Title metadata fields of a file under Windows. I got the
win32 extensions installed and found a few things that look like they
should work, though I'm not getting the result I would expect.
Hopefully someone has worked through this area and can point me in the
right direction.
so after various imports I try the following:
file=pythoncom.StgOpenStorageEx(fname, m, storagecon.STGFMT_FILE, 0 ,
pythoncom.IID_IPropertySetStorage)
summ=file.Create(pythoncom.FMTID_SummaryInformation,
pythoncom.IID_IPropertySetStorage,
storagecon.PROPSETFLAG_DEFAULT,
storagecon.STGM_READWRITE|storagecon.STGM_CREATE|
storagecon.STGM_SHARE_EXCLUSIVE)
everything seems fine so far, until I try and write which doesn't seem
to do anything. I tried the following three ways:
summ.WriteMultiple((storagecon.PIDSI_AUTHOR, storagecon.PIDSI_TITLE),
('Author', 'Title'))
summ.WriteMultiple((4,2 ), ('Author', 'Title'))
summ.WritePropertyNames((4,2 ), ('Author', 'Title'))
Any advice would be most appreciated!
Matt
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Re: Get the class name
On 2009-06-07 15:41, Tuomas Vesterinen wrote: Kless wrote: Is there any way of to get the class name to avoid to have that write it? --- class Foo: super(Foo, self) --- * Using Py 2.6.2 class Foo(object): ... def cls(self): ... return self.__class__ ... Foo().cls() class '__main__.Foo' You definitely don't want to use that for super(). If you actually have an instance of a subclass of Foo, you will be giving the wrong information. Basically, there is no (sane) way to do what the OP wants. If there were, that information would not be necessary to give to super(). -- Robert Kern I have come to believe that the whole world is an enigma, a harmless enigma that is made terrible by our own mad attempt to interpret it as though it had an underlying truth. -- Umberto Eco -- http://mail.python.org/mailman/listinfo/python-list
Re: multi-core software
Lew wrote: div class=moz-text-flowed style=font-family: -moz-fixedScott David Daniels wrote: the nub of the problem is not on the benchmarks. There is something to be said for the good old daays when you looked up the instruction timings that you used in a little document for your machine, and could know the cost of any loop. We are faster now, but part of the cost of that speed is that timing is a black art. Those good old days never existed. Those manuals never accounted for things that affected timing even then, like memory latency or refresh time. SRAM cache made things worse, since the published timings never mentioned cache-miss delays. Though memory cache might seem a recent innovation, it's been around a while. It would be challenging to find any published timing since the commercialization of computers that would actually tell the cost of any loop. Things got worse when chips like the '86 family acquired multiple instructions for doing loops, still worse when pre-fetch pipelines became deeper and wider, absolutely Dark Art due to multi-level memory caches becoming universal, and throw-your-hands-up-and-leave-for-the-corner-bar with multiprocessor NUMA systems. OSes and high-level languages complicate the matter - you never know how much time slice you'll get or how your source got compiled or optimized by run-time. So the good old days are a matter of degree and self-deception - it was easier to fool ourselves then that we could at least guess timings proportionately if not absolutely, but things definitely get more unpredictable over evolution. Nonsense. The 6502 with static memory was precisely predictable, and many programmers (working in machine language, naturally) counted on it. Similarly the Novix 4000, when programmed in its native Forth. And previous to that, I worked on several machines (in fact, I wrote the assembler and debugger for two of them) where the only variable was the delay every two milliseconds for dynamic memory refresh. Separate control memory and data memory, and every instruction precisely clocked. No instruction prefetch, no cache memory. What you see is what you get. Would I want to go back there? No. Sub-megaherz clocks with much less happening on each clock means we were operating at way under .01% of present day. -- http://mail.python.org/mailman/listinfo/python-list
Re: multi-core software
Ken T. wrote: On Sun, 07 Jun 2009 11:16:46 -0400, Lew wrote: So the good old days are a matter of degree and self-deception - it was easier to fool ourselves then that we could at least guess timings proportionately if not absolutely, but things definitely get more unpredictable over evolution. As I recall I could get exact timings on my 6502 based Commodore 64. The issues you speak of simply weren't issues. Let's not forget Elite for the 6502 exploiting predictable performance in order to switch graphics modes partway down the vsync! -- Dr Jon D Harrop, Flying Frog Consultancy Ltd. http://www.ffconsultancy.com/?u -- http://mail.python.org/mailman/listinfo/python-list
Re: multi-core software
Jon Harrop wrote: Arved Sandstrom wrote: Lew wrote: Interesting distinction. Would it be fair to compare concurrent programming to the bricks used to build the parallel program's edifice? Way too much of a fine distinction. While they are in fact different, the point of concurrent programming is to structure programs as a group of computations, which can be executed in parallel (however that might actually be done depending on how many processors there are). No. Concurrent programming is about interleaving computations in order to reduce latency. Nothing to do with parallelism. Jon, I do concurrent programming all the time, as do most of my peers. Way down on the list of why we do it is the reduction of latency. AHS -- http://mail.python.org/mailman/listinfo/python-list
Re: Get the class name
On Jun 7, 1:14 pm, Kless jonas@googlemail.com wrote: Is there any way of to get the class name to avoid to have that write it? --- class Foo: super(Foo, self) --- * Using Py 2.6.2 If you are using emacs you can use the put the following elisp code in your .emacs file, defines a command to automatically insert the a super call with the class and method name filled in: http://code.activestate.com/recipes/522990/ Carl Banks -- http://mail.python.org/mailman/listinfo/python-list
Re: how to transfer my utf8 code saved in a file to gbk code
On Jun 7, 11:25 pm, John Machin sjmac...@lexicon.net wrote:
On Jun 7, 10:55 pm, higer higerinbeij...@gmail.com wrote:
My file contains such strings :
\xe6\x97\xa5\xe6\x9c\x9f\xef\xbc\x9a
Are you sure? Does that occupy 9 bytes in your file or 36 bytes?
It was saved in a file, so it occupy 36 bytes. If I just use a
variable to contain this string, it can certainly work out correct
result,but how to get right answer when reading from file.
I want to read the content of this file and transfer it to the
corresponding gbk code,a kind of Chinese character encode style.
Everytime I was trying to transfer, it will output the same thing no
matter which method was used.
It seems like that when Python reads it, Python will taks '\' as a
common char and this string at last will be represented as \\xe6\\x97\
\xa5\\xe6\\x9c\\x9f\\xef\\xbc\\x9a , then the \ can be 'correctly'
output,but that's not what I want to get.
Anyone can help me?
try this:
utf8_data = your_data.decode('string-escape')
unicode_data = utf8_data.decode('utf8')
# unicode derived from your sample looks like this 日期： is that what
you expected?
You are right , the result is 日期 which I just expect. If you save the
string in a variable, you surely can get the correct result. But it is
just a sample, so I give a short string, what if so many characters in
a file?
gbk_data = unicode_data.encode('gbk')
I have tried this method which you just told me, but unfortunately it
does not work(mess code).
If that doesn't work, do three things:
(1) give us some unambiguous hard evidence about the contents of your
data:
e.g. # assuming Python 2.x
My Python versoin is 2.5.2
your_data = open('your_file.txt', 'rb').read(36)
print repr(your_data)
print len(your_data)
print your_data.count('\\')
print your_data.count('x')
The result is:
'\\xe6\\x97\\xa5\\xe6\\x9c\\x9f\\xef\\xbc\\x9a'
36
9
9
(2) show us the source of the script that you used
def UTF8ToChnWords():
f = open(123.txt,rb)
content=f.read()
print repr(content)
print len(content)
print content.count(\\)
print content.count(x)
pass
if __name__ == '__main__':
UTF8ToChnWords()
(3) Tell us what doesn't work means in this case
It doesn't work because no matter in what way we deal with it we often
get 36 bytes string not 9 bytes.Thus, we can not get the correct
answer.
Cheers,
John
Thank you very much,
higer
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Re: how to transfer my utf8 code saved in a file to gbk code
On Jun 8, 8:20 am, MRAB pyt...@mrabarnett.plus.com wrote: John Machin wrote: On Jun 8, 12:13 am, R. David Murray rdmur...@bitdance.com wrote: higer higerinbeij...@gmail.com wrote: My file contains such strings : \xe6\x97\xa5\xe6\x9c\x9f\xef\xbc\x9a If those bytes are what is in the file (and it sounds like they are), then the data in your file is not in UTF8 encoding, it is in ASCII encoded as hexidecimal escape codes. OK, I'll bite: what *ASCII* character is encoded as either \xe6 or r\xe6 by what mechanism in which parallel universe? Maybe he means that the file itself is in ASCII. Yes,my file itself is in ASCII. -- http://mail.python.org/mailman/listinfo/python-list
Re: multi-core software
Arved Sandstrom wrote: Jon Harrop wrote: Arved Sandstrom wrote: Lew wrote: Interesting distinction. Would it be fair to compare concurrent programming to the bricks used to build the parallel program's edifice? Way too much of a fine distinction. While they are in fact different, the point of concurrent programming is to structure programs as a group of computations, which can be executed in parallel (however that might actually be done depending on how many processors there are). No. Concurrent programming is about interleaving computations in order to reduce latency. Nothing to do with parallelism. Jon, I do concurrent programming all the time, as do most of my peers. Way down on the list of why we do it is the reduction of latency. What is higher on the list? -- Dr Jon D Harrop, Flying Frog Consultancy Ltd. http://www.ffconsultancy.com/?u -- http://mail.python.org/mailman/listinfo/python-list
Re: multi-core software
On Mon, 08 Jun 2009 02:39:40 +0100, Jon Harrop wrote: Ken T. wrote: On Sun, 07 Jun 2009 11:16:46 -0400, Lew wrote: So the good old days are a matter of degree and self-deception - it was easier to fool ourselves then that we could at least guess timings proportionately if not absolutely, but things definitely get more unpredictable over evolution. As I recall I could get exact timings on my 6502 based Commodore 64. The issues you speak of simply weren't issues. Let's not forget Elite for the 6502 exploiting predictable performance in order to switch graphics modes partway down the vsync! That actually didn't require predictable timing. You could tell the video chip to send you an interrupt when it got to a given scan line. I used this myself. Elite was cool though. I wasted many hours playing that game. -- Ken T. http://www.electricsenator.net Duct tape is like the force. It has a light side, and a dark side, and it holds the universe together ... -- Carl Zwanzig -- http://mail.python.org/mailman/listinfo/python-list
Re: pylint naming conventions?
On Sun, Jun 7, 2009 at 9:23 AM, Esmailebo...@hotmail.com wrote: Ben Finney wrote: Esmail ebo...@hotmail.com writes: I am confused by pylint's naming conventions, I don't think the are in tune with Python's style recommendations (PEP 8?) Anyone else think this? It's hard to know, without examples. Can you give some output of pylint that you think doesn't agree with PEP 8? Sure, I will next time I have a nice self-contained example. Perhaps not that many people are using pylint? I was expecting a bunch of messages either contradicting my observation or agreeing with it :-) .. but perhaps this indicates that there's no issue. It is my understanding that it does check for PEP8 names. Even if it doesn't it is really easy to change. If you run 'pylint --generate-rcfile' (i think) it will output the configuration that it is using. You can then save this off and customize it. I'll try to come up with a nice short code example in the next few days to demonstrate what I think the problem is and post it, thanks for the suggestion. If you didn't have an example handy what prompted you to start this thread? -- David blog: http://www.traceback.org twitter: http://twitter.com/dstanek -- http://mail.python.org/mailman/listinfo/python-list
Re: multi-core software
George Neuner gneun...@comcast.net writes: Even the lightest weight user space (green) threads need a few hundred instructions, minimum, to amortize the cost of context switching. I thought the definition of green threads was that multiplexing them doesn't require context switches. -- http://mail.python.org/mailman/listinfo/python-list
Re: multi-core software
Jeff M. mass...@gmail.com writes: Even the lightest weight user space (green) threads need a few hundred instructions, minimum, to amortize the cost of context switching There's always a context switch. It's just whether or not you are switching in/out a virtual stack and registers for the context or the hardware stack/registers. I don't see the hundreds of instructions in that case. http://shootout.alioth.debian.org/u32q/benchmark.php?test=threadringlang=ghcid=3 shows GHC doing 50 million lightweight thread switches in 8.47 seconds, passing a token around a thread ring. Almost all of that is probably spent acquiring and releasing the token's lock as the token is passed from one thread to another. That simply doesn't leave time for hundreds of instructions per switch. -- http://mail.python.org/mailman/listinfo/python-list
Re: can it be shorter?
Aaron Brady castiro...@gmail.com writes:
url+= { '/': '' }.get( url[ -1 ], '/' )
Shorter is always better.
url = url.rstrip('/') + '/'
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Re: multi-core software
Paul Rubin wrote: Jeff M. mass...@gmail.com writes: Even the lightest weight user space (green) threads need a few hundred instructions, minimum, to amortize the cost of context switching There's always a context switch. It's just whether or not you are switching in/out a virtual stack and registers for the context or the hardware stack/registers. I don't see the hundreds of instructions in that case. http://shootout.alioth.debian.org/u32q/benchmark.php?test=threadringlang=ghcid=3 shows GHC doing 50 million lightweight thread switches in 8.47 seconds, passing a token around a thread ring. Almost all of that is probably spent acquiring and releasing the token's lock as the token is passed from one thread to another. That simply doesn't leave time for hundreds of instructions per switch. And Haskell is not exactly fast... -- Dr Jon D Harrop, Flying Frog Consultancy Ltd. http://www.ffconsultancy.com/?u -- http://mail.python.org/mailman/listinfo/python-list
Re: multi-core software
Scott David Daniels wrote: Lew wrote: Scott David Daniels wrote: the nub of the problem is not on the benchmarks. There is something to be said for the good old daays when you looked up the instruction timings that you used in a little document for your machine, and could know the cost of any loop. We are faster now, but part of the cost of that speed is that timing is a black art. Those good old days never existed. Those manuals never accounted for things that affected timing even then, like memory latency or refresh time. Well, as Gilbert and Sullivan wrote: - What, never? - No, never! - What, Never? - Well, hardly ever. Look up the LGP-30. It was quite predictable. It has been a while. Same for early ARMs. -- Dr Jon D Harrop, Flying Frog Consultancy Ltd. http://www.ffconsultancy.com/?u -- http://mail.python.org/mailman/listinfo/python-list
Re: spammers on pypi
Lawrence D'Oliveiro wrote: In message dd8295d3-61ab-4cc9-86b8-1e04f3edd...@f16g2000vbf.googlegroups.com, joep wrote: Is there a way to ban spammers from pypi? Yes, but it doesn't work. And if you ever do discover something that _does_ work: (1) You'll have discovered perpetual motion. (2) You'll probably get terribly rich from selling it. (3) You'll probably advertize your new solution via bulk e-mail to all e-mail addresses you know of that might be interested in learning of your great discovery. :-) --Scott David Daniels scott.dani...@acm.org -- http://mail.python.org/mailman/listinfo/python-list
Re: multi-core software
Lew wrote: Scott David Daniels wrote: the nub of the problem is not on the benchmarks. There is something to be said for the good old daays when you looked up the instruction timings that you used in a little document for your machine, and could know the cost of any loop. We are faster now, but part of the cost of that speed is that timing is a black art. Those good old days never existed. Those manuals never accounted for things that affected timing even then, like memory latency or refresh time. Well, as Gilbert and Sullivan wrote: - What, never? - No, never! - What, Never? - Well, hardly ever. Look up the LGP-30. It was quite predictable. It has been a while. --Scott David Daniels scott.dani...@acm.org -- http://mail.python.org/mailman/listinfo/python-list
Re: multi-core software
On Fri, 5 Jun 2009 18:15:00 + (UTC), Kaz Kylheku kkylh...@gmail.com wrote, quoted or indirectly quoted someone who said : Even for problems where it appears trivial, there can be hidden issues, like false cache coherency communication where no actual sharing is taking place. Or locks that appear to have low contention and negligible performance impact on ``only'' 8 processors suddenly turn into bottlenecks. Then there is NUMA. A given address in memory may be RAM attached to the processor accessing it, or to another processor, with very different access costs. Could what you are saying be summed up by saying, The more threads you have the more important it is to keep your threads independent, sharing as little data as possible. -- Roedy Green Canadian Mind Products http://mindprod.com Never discourage anyone... who continually makes progress, no matter how slow. ~ Plato 428 BC died: 348 BC at age: 80 -- http://mail.python.org/mailman/listinfo/python-list
openhook
Can anybody tell me what is meant by 'openhook' ? -- http://mail.python.org/mailman/listinfo/python-list
Re: The Complexity And Tedium of Software Engineering
On 2009-06-05 21:03:33 +0100, Kenneth Tilton kentil...@gmail.com said: When progress stops we will have time to polish our systems, not before. Is that an endorsement of mediocrity? -- JFB -- http://mail.python.org/mailman/listinfo/python-list
Re: multi-core software
Roedy Green see_webs...@mindprod.com.invalid writes: On Fri, 5 Jun 2009 18:15:00 + (UTC), Kaz Kylheku kkylh...@gmail.com wrote, quoted or indirectly quoted someone who said : Even for problems where it appears trivial, there can be hidden issues, like false cache coherency communication where no actual sharing is taking place. Or locks that appear to have low contention and negligible performance impact on ``only'' 8 processors suddenly turn into bottlenecks. Then there is NUMA. A given address in memory may be RAM attached to the processor accessing it, or to another processor, with very different access costs. Could what you are saying be summed up by saying, The more threads you have the more important it is to keep your threads independent, sharing as little data as possible. Absolutely... not a new observation, either, as it follows directly from Amdahl's law. -- http://mail.python.org/mailman/listinfo/python-list
Re: The Complexity And Tedium of Software Engineering
verec wrote: On 2009-06-05 21:03:33 +0100, Kenneth Tilton kentil...@gmail.com said: When progress stops we will have time to polish our systems, not before. Is that an endorsement of mediocrity? No, of General Patton. hth, kt -- http://mail.python.org/mailman/listinfo/python-list
can it be shorter?
I want to ensure that the url ends with a '/', now I have to do thisa like below. url = url + '' if url[-1] == '/' else '/' Is there a better way? -- http://mail.python.org/mailman/listinfo/python-list
Get the class name
Is there any way of to get the class name to avoid to have that write it? --- class Foo: super(Foo, self) --- * Using Py 2.6.2 -- http://mail.python.org/mailman/listinfo/python-list
Re: pylint naming conventions?
David Stanek dsta...@dstanek.com writes: On Sun, Jun 7, 2009 at 9:23 AM, Esmailebo...@hotmail.com wrote: I'll try to come up with a nice short code example in the next few days to demonstrate what I think the problem is and post it, thanks for the suggestion. If you didn't have an example handy what prompted you to start this thread? My understanding of Esmail's original message was that, like many of us on first running ‘pylint’ against an existing code base, the output is astonishingly verbose and tedious to read. By the above I presume he's being a good forum member and trying to find a minimal example that shows the problem clearly :-) -- \“Kill myself? Killing myself is the last thing I'd ever do.” | `\—Homer, _The Simpsons_ | _o__) | Ben Finney -- http://mail.python.org/mailman/listinfo/python-list
Re: how to transfer my utf8 code saved in a file to gbk code
higer higerinbeij...@gmail.com wrote in message
news:0c786326-1651-42c8-ba39-4679f3558...@r13g2000vbr.googlegroups.com...
On Jun 7, 11:25 pm, John Machin sjmac...@lexicon.net wrote:
On Jun 7, 10:55 pm, higer higerinbeij...@gmail.com wrote:
My file contains such strings :
\xe6\x97\xa5\xe6\x9c\x9f\xef\xbc\x9a
Are you sure? Does that occupy 9 bytes in your file or 36 bytes?
It was saved in a file, so it occupy 36 bytes. If I just use a
variable to contain this string, it can certainly work out correct
result,but how to get right answer when reading from file.
Did you create this file? If it is 36 characters, it contains literal
backslash characters, not the 9 bytes that would correctly encode as UTF-8.
If you created the file yourself, show us the code.
I want to read the content of this file and transfer it to the
corresponding gbk code,a kind of Chinese character encode style.
Everytime I was trying to transfer, it will output the same thing no
matter which method was used.
It seems like that when Python reads it, Python will taks '\' as a
common char and this string at last will be represented as \\xe6\\x97\
\xa5\\xe6\\x9c\\x9f\\xef\\xbc\\x9a , then the \ can be 'correctly'
output,but that's not what I want to get.
Anyone can help me?
try this:
utf8_data = your_data.decode('string-escape')
unicode_data = utf8_data.decode('utf8')
# unicode derived from your sample looks like this 日期： is that what
you expected?
You are right , the result is 日期 which I just expect. If you save the
string in a variable, you surely can get the correct result. But it is
just a sample, so I give a short string, what if so many characters in
a file?
gbk_data = unicode_data.encode('gbk')
I have tried this method which you just told me, but unfortunately it
does not work(mess code).
How are you determining this is 'mess code'? How are you viewing the
result? You'll need to use a viewer that understands GBK encoding, such as
Chinese Window's Notepad.
If that doesn't work, do three things:
(1) give us some unambiguous hard evidence about the contents of your
data:
e.g. # assuming Python 2.x
My Python versoin is 2.5.2
your_data = open('your_file.txt', 'rb').read(36)
print repr(your_data)
print len(your_data)
print your_data.count('\\')
print your_data.count('x')
The result is:
'\\xe6\\x97\\xa5\\xe6\\x9c\\x9f\\xef\\xbc\\x9a'
36
9
9
(2) show us the source of the script that you used
def UTF8ToChnWords():
f = open(123.txt,rb)
content=f.read()
print repr(content)
print len(content)
print content.count(\\)
print content.count(x)
Try:
utf8data = content.decode('string-escape')
unicodedata = utf8data.decode('utf8')
gbkdata = unicodedata.encode('gbk')
print len(gbkdata),repr(gbkdata)
open(456.txt,wb).write(gbkdata)
The print should give:
6 '\xc8\xd5\xc6\xda\xa3\xba'
This is correct for GBK encoding. 456.txt should contain the 6 bytes of GBK
data. View the file with a program that understand GBK encoding.
-Mark
--
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[issue4749] Issue with RotatingFileHandler logging handler on Windows
Frans frans.van.nieuwenho...@gmail.com added the comment: I ran into the same problem with RotatingFileHandler from a multithreaded daemon under Ubuntu. I Googled around and found the ConcurrentLogHandler on pypi (http://pypi.python.org/pypi/ConcurrentLogHandler). It solved the problem. -- nosy: +Frans ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue4749 ___ ___ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue6228] round() error
New submission from steve21 steve872929...@yahoo.com.au: I wish to round the float 697.04157958254996 to 10 decimal digits after the decimal point. $ python3.0 Python 3.0.1 (r301:69556, Jun 7 2009, 14:51:41) [GCC 4.3.2 20081105 (Red Hat 4.3.2-7)] on linux2 Type help, copyright, credits or license for more information. 697.04157958254996 697.04157958254996 # python float can represent this number exactly 697.0415795825 # this is the expected result 697.04157958250005 # this is the closest python float representation round(697.04157958254996, 10) 697.04157958259998 # error round() gives a result that is closer to 697.0415795826 than the expected result of 697.0415795825 - it has not rounded to the closest 10th decimal digit after the decimal point. (python 2.6.2 has the same problem) -- messages: 89029 nosy: steve21 severity: normal status: open title: round() error type: behavior versions: Python 2.6, Python 3.0 ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue6228 ___ ___ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue6229] Installation python on mac
New submission from eric mul...@gmx.ch: Hello i wan't to install the python 3.0 on my mac. the python image, .dmg file, i download from this site, run the installation. After this, the framework doesn't installation in the folder /System/Library/Frameworks/Python.framework. How can i change the installation folder? thx kostonstyle -- messages: 89030 nosy: kostonstyle severity: normal status: open title: Installation python on mac versions: Python 3.0 ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue6229 ___ ___ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
