Python Engineers
Good morning, I'm having trouble finding experienced Python engineers in the Annapolis/DC area. Is this list an appropriate place to look? Thanks, Bill Currence -- http://mail.python.org/mailman/listinfo/python-announce-list Support the Python Software Foundation: http://www.python.org/psf/donations.html
GPCE'08 Call for Participation
http://gpce08.gpce.org Seventh International Conference on Generative Programming and Component Engineering (GPCE'08) Nashville, Tennessee (co-located with OOPSLA 2008) * Only Six Days Left for Early Registration * *** CALL FOR PARTICIPATION Generative and component approaches are revolutionizing software development similar to how automation and components revolutionized manufacturing. Generative Programming (developing programs that synthesize other programs), Component Engineering (raising the level of modularization and analysis in application design), and Domain-Specific Languages (elevating program specifications to compact domain-specific notations that are easier to write, maintain, and analyze) are key technologies for automating program development. GPCE provides a venue for researchers and practitioners interested in foundational techniques for enhancing the productivity, quality, and time-to-market in software development that stems from deploying standard components and automating program generation. In addition to exploring cutting-edge techniques for developing generative and component-based software, our goal is to foster further cross-fertilization between the software engineering research community and the programming languages community. GPCE 2008 will be co-located with OOPSLA, in Nashville, Tennessee. The GPCE technical program will take place on Oct. 19-20, before the OOPSLA technical program begins. Other GPCE events (workshops and tutorials) will run in parallel with OOPSLA events on Oct 21-23. GPCE'08 is sponsored by ACM SIGPLAN, in cooperation with ACM SIGSOFT. GPCE'08 proceedings published by ACM Press. For full conference program and the latest news, check the GPCE'08 web site (http://gpce08.gpce.org). REGISTRATION Registration for GPCE'08 is handled through the OOPSLA registration page (http://www.regmaster.com/conf/oopsla2008.html). Early registration deadline is Septermber 11. *** TECHNICAL PROGRAM Sunday, October 19 8:50-9:00 Welcome 9:00-10:00 Keynote Session Chair: Julia Lawall * Emerging Challenges for Large Scale Systems Integration Dr. Andrew Fano (Accenture) 10:30-12:00 Technical papers 1 Session Chair: Julia Lawall * Code Generation to Support Static and Dynamic Composition of Software Product Lines Marko Rosenmueller, Norbert Siegmund, Sven Apel and Gunter Saake. * Efficient Compilation Techniques for Large Scale Feature Models Marcilio Mendonca, Andrzej Wasowski, Krzysztof Czarnecki and Don Cowan. * On the Modularity of Feature Interactions Chang Hwan Peter Kim, Christian Kaestner and Don Batory. 13:30-15:00 Technical papers 2 Session Chair: Jaakko Jarvi * Using Simple Mathematics as a Modeling Language Don Batory. * From Generic to Specific: Off-line Optimization for General Constraint Solver Ye Zhang, Torben Amtoft and Flemming Nielson. * Generating Incremental Implementations of Object-Set Queries Tom Rothamel and Yanhong A. Liu. 15:30-17:00 Technical papers 3 Session Chair: Aniruddha Gokhale * Integrating Semantics and Compilation Peter Gottschling and Andrew Lumsdaine. * Generating Customized Verifiers for Automatically Generated Code Ewen Denney and Bernd Fischer. * Property Models: From Incidental Algorithms to Reusable Components Jaakko Jarvi, Mat Marcus, Sean Parent, John Freeman and Jacob Smith. 17:00-17:30 PC chair's report Monday, October 20 9:00-10:00 Keynote Session Chair: William Cook * Fundamentalist Functional Programming Erik Meijer (Microsoft) 10:30-12:00 Technical papers 4 Session Chair: William Cook * Feature Featherweight Java: A Calculus for Feature-Oriented Programming and Stepwise Refinement Sven Apel, Christian Kastner and Christian Lengauer. * Lightweight Dependent Classes Tetsuo Kamina and Tetsuo Tamai. * Typing Communicating Component Assemblages Michael Lienhardt, Vivien Quema, Alan Schmitt and Jean-Bernard Stefani. 14:00-15:00 Technical papers 5 Session Chair: David Abrahams * Polymorphic Embedding of DSLs Christian Hofer, Klaus Ostermann, Tillmann Rendel and Adriaan Moors. * Pantaxou: a Domain-Specific Language for Developing Safe Coordination Services Julien Mercadal, Nicolas Palix, Charles Consel and Julia Lawall. 15:30-17:00 Technical papers 6 Session Chair: Mark Grechanik * Program Refactoring using Functional Aspects Sven Apel, Christian Kastner and Don Batory. * Rigorous and Practical Refactoring-Based Framework Upgrade Ilie Savga, Michael Rudolf, Sebastian Gotz and Uwe Assmann. * An abstraction for reusable MDD components Vinay Kulkarni and Sreedhar Reddy.-- http://mail.python.org/mailman/listinfo/python-announce-list Support the Python Software Foundation: http://www.python.org/psf/donations.html
[ANN] pysqlite 2.5.0 released
-BEGIN PGP SIGNED MESSAGE- Hash: SHA1 pysqlite 2.5.0 released === I'm pleased to announce the availability of pysqlite 2.5.0. This is a release with major new features. Go to http://pysqlite.org/ for downloads, online documentation and reporting bugs. What is pysqlite? pysqlite is a DB-API 2.0-compliant database interface for SQLite. SQLite is a in-process library that implements a self-contained, serverless, zero-configuration, transactional SQL database engine. pysqlite makes this powerful embedded SQL engine available to Python programmers. It stays compatible with the Python database API specification 2.0 as much as possible, but also exposes most of SQLite's native API, so that it is for example possible to create user-defined SQL functions and aggregates in Python. If you need a relational database for your applications, or even small tools or helper scripts, pysqlite is often a good fit. It's easy to use, easy to deploy, and does not depend on any other Python libraries or platform libraries, except SQLite. SQLite itself is ported to most platforms you'd ever care about. It's often a good alternative to MySQL, the Microsoft JET engine or the MSDE, without having any of their license and deployment issues. pysqlite can be downloaded from http://pysqlite.org/ - Sources and Windows binaries for Python 2.5, 2.4 and Python 2.3 are available. === CHANGES === - - Windows binaries are now cross-built using mingw on Linux - - import various fixes from Python 2.6 version - - Connection has new method iterdump() that allows you to create a script file that can be used to clone a database - - the docs are now built using Sphinx and were imported from Python 2.6's sqlite3 module - - Connection.enable_load_extension(enabled) to allow/disallow extension loading. Allows you to use fulltext search extension, for example ;-) - - Give the remaining C functions used in multiple .c source files the pysqlite_ prefix. - - Release GIL during sqlite3_prepare() calls for better concurrency. - - Automatically download the SQLite amalgamation when building statically. -BEGIN PGP SIGNATURE- Version: GnuPG v1.4.6 (GNU/Linux) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org iD8DBQFIwZV3dIO4ozGCH14RAp1YAJwPIdgtCZY7E8YcDUjO/dzoAThblgCggfhs OATfXAb6JYXqb8eTadl9k74= =KU3f -END PGP SIGNATURE- -- http://mail.python.org/mailman/listinfo/python-announce-list Support the Python Software Foundation: http://www.python.org/psf/donations.html
ANN: cocos2d v0.3.0 released
ANN: cocos2d v0.3.0 released get it at: http://cocos2d.org see our 45 minutes presentation of cocos2d at: http://blip.tv/file/1075646/ Whats new: -- v0.3.0 - September 5th, 2008 - Added particle systems: Sun, Fire, Fireworks, Meteor, Galaxy, Flower, Exposion, Spiral - Added lerp actions - Applied patch by naveen.michaudagrawal - Applied patch by Kao Cardoso Félix - Applied patch by JeanpierreDA - Fixed Camera once locate bug - Many bugfixes - Primitive vector based line drawing. - Tile-map editor About cocos2d: -- cocos2d is a framework for building 2D games, demos, and other graphical/interactive applications. Main Features: -- * Flow control: Manage the flow control between different scenes in an easy way * Sprites: Fast and easy sprites * Actions: Just tell sprites what you want them to do. Composable actions like move, rotate, scale and much more * Effects: Effects like waves, twirl, lens and much more * Tiled Maps: Support for rectangular and hexagonal tiled maps * Transitions: Move from scene to scene with style * Menus: Built in classes to create menus * Text Rendering: Label and HTMLLabel with action support * Documentation: Programming Guide + API Reference + Video Tutorials + Lots of simple tests showing how to use it * Built-in Python Interpreter: For debugging purposes * BSD License: Just use it * Pyglet Based: No external dependencies * OpenGL Based: Hardware Acceleration more info: -- home: http://cocos2d.org download: http://los-cocos.googlecode.com/files/cocos2d-0.3.0.tar.gz -- http://mail.python.org/mailman/listinfo/python-announce-list Support the Python Software Foundation: http://www.python.org/psf/donations.html
short python talk available from osbootcamp.org
Hi All, Open Source Bootcamp (osbootcamp) teaches skills with open source. We recently had a python talk which we've recorded and made freely available from the osbootcamp.org videos section. Enjoy! Andrew http://osbootcamp.org -- http://mail.python.org/mailman/listinfo/python-announce-list Support the Python Software Foundation: http://www.python.org/psf/donations.html
Release 0.3 of Evoque Templating
Happy to announce release version 0.3 of the Evoque Templating engine
for python. Other than the bug fixes, a couple recent changes that are
particularly worthy of mention are:
- Significantly more dynamic
In particular you can now do things like determine the base template
of a template hierarchy chain dynamically at runtime -- how it is done
boils down to just using a variable to select which template to to use
as base template i.e. a template just declares an overlay directive
such as $overlay{name=my_site_theme} and the runtime value of
my_site_theme will determine which template will be overlaid. This can
be a very nice way to manage a site theme as per user preferences. For
further explanations, see:
http://evoque.gizmojo.org/howto/site-template/
- Seamless integration with Pylons
The code for using Evoque as the templating engine in a Pylons
application is included in the distribution, and detailed description
of the process is at:
http://evoque.gizmojo.org/ext/pylons/
What is Evoque?
Evoque is a lightweight full-featured generic text templating engine
for python with sandbox-ability, versatility and simplicity as key
feature priorities. In spite of its feature-richness, it has a small
footprint (972 SLOC) and is very fast.
[license] Academic Free License version 3.0
[documentation] http://evoque.gizmojo.org/
[features] http://evoque.gizmojo.org/features/
[download] http://evoque.gizmojo.org/download/
[installation] easy_install evoque
--
http://mail.python.org/mailman/listinfo/python-announce-list
Support the Python Software Foundation:
http://www.python.org/psf/donations.html
[ANN] Leipzig Python User Group Meeting, September 09, 2008, 08:00 pm
=== Leipzig Python User Group === We will meet on Tuesday, September 09 at 8:00 pm at the training center of Python Academy in Leipzig, Germany ( http://www.python-academy.com/center/find.html ). Food and soft drinks are provided. Please send a short confirmation mail to [EMAIL PROTECTED] , so we can prepare appropriately. Everybody who uses Python, plans to do so or is interested in learning more about the language is welcome. While the meeting language will be mainly German, we will provide English translation if needed. Current information about the meetings are at http://www.python-academy.com/user-group . Stefan == Leipzig Python User Group === Wir treffen uns am Dienstag, 09.09.2008 um 20:00 Uhr im Schulungszentrum der Python Academy in Leipzig ( http://www.python-academy.de/Schulungszentrum/anfahrt.html ). Für das leibliche Wohl wird gesorgt. Eine Anmeldung unter [EMAIL PROTECTED] wäre nett, damit wir genug Essen besorgen können. Willkommen ist jeder, der Interesse an Python hat, die Sprache bereits nutzt oder nutzen möchte. Aktuelle Informationen zu den Treffen sind unter http://www.python-academy.de/User-Group zu finden. Viele Grüße Stefan -- http://mail.python.org/mailman/listinfo/python-announce-list Support the Python Software Foundation: http://www.python.org/psf/donations.html
[ANN] ftputil 2.3 released
ftputil 2.3 is now available from http://ftputil.sschwarzer.net/download . Changes since version 2.2.4 --- ftputil has got support for the ``with`` statement which was introduced by Python 2.5. You can now construct host and remote file objects in ``with`` statements and have them closed automatically (contributed by Roger Demetrescu). See the documentation for examples. What is ftputil? ftputil is a high-level FTP client library for the Python programming language. ftputil implements a virtual file system for accessing FTP servers, that is, it can generate file-like objects for remote files. The library supports many functions similar to those in the os, os.path and shutil modules. ftputil has convenience functions for conditional uploads and downloads, and handles FTP clients and servers in different timezones. Read the documentation at http://ftputil.sschwarzer.net/documentation . License --- ftputil is Open Source software, released under the revised BSD license (see http://www.opensource.org/licenses/bsd-license.php ). Stefan -- http://mail.python.org/mailman/listinfo/python-announce-list Support the Python Software Foundation: http://www.python.org/psf/donations.html
Jython 2.5 Alpha 2 Released!
On behalf of the Jython development team, I'm pleased to announce that Jython 2.5a2+ is available for download http://voxel.dl.sourceforge.net/sourceforge/jython/jython_installer-2.5a2.jar. See the installation instructions http://jython.org/Project/installation.html. Django runs pretty well on this release. I am attending Djangocon where Jim Baker and Leo Soto will be presenting on Django on Jython, and I wanted them to be able to tell people to grab a release instead of telling them to grab Jython from svn. There are many bug fixes, but also many bugs that have not yet been fixed. This is an alpha release so be careful! -- http://mail.python.org/mailman/listinfo/python-announce-list Support the Python Software Foundation: http://www.python.org/psf/donations.html
Re: use str as variable name
On Fri, Sep 5, 2008 at 9:16 PM, Bruno Desthuilliers [EMAIL PROTECTED] wrote: Marco Bizzarri a écrit : Just a question: generic functions are not meant in the sense of generic functions of CLOS, am I right? Nope. Just generic in the sense that they accept any object implementing a very minimal interface. If you want something like CLOS multimethods, you may be interested in Philip Eby's ruledispatch. Even though I loved them when I used at university, I'm not looking for them right now... but nice to know that they are available under python :-) -- Marco Bizzarri http://notenotturne.blogspot.com/ http://iliveinpisa.blogspot.com/ -- http://mail.python.org/mailman/listinfo/python-list
Re: use str as variable name
On Sat, Sep 6, 2008 at 7:52 AM, Fredrik Lundh [EMAIL PROTECTED] wrote: Marco Bizzarri wrote: (...as Bruno implies, setattr(), len() et al can be and should be viewed as generic functions. Just a question: generic functions are not meant in the sense of generic functions of CLOS, am I right? it's meant in exactly that sense: len(L) means of all len() implementations available to the runtime, execute the most specific code we have for the object L. It is a generic functions like a CLOS one, as long as we remain to one parameter. I mean, there will be just one implemenatation of foo(bar, man) which the python interpretr can find; am I right? -- Marco Bizzarri http://notenotturne.blogspot.com/ http://iliveinpisa.blogspot.com/ -- http://mail.python.org/mailman/listinfo/python-list
Re: use str as variable name
On Sep 6, 8:02 am, Marco Bizzarri [EMAIL PROTECTED] wrote: On Fri, Sep 5, 2008 at 9:16 PM, Bruno Desthuilliers [EMAIL PROTECTED] wrote: Marco Bizzarri a écrit : Just a question: generic functions are not meant in the sense of generic functions of CLOS, am I right? Nope. Just generic in the sense that they accept any object implementing a very minimal interface. If you want something like CLOS multimethods, you may be interested in Philip Eby's ruledispatch. Even though I loved them when I used at university, I'm not looking for them right now... but nice to know that they are available under python :-) Actually they are already available in the standard library but they are undocumented. See for instance this recent blog post of mine: http://www.artima.com/weblogs/viewpost.jsp?thread=237764 (as well as the comment below by P.J. Eby) -- http://mail.python.org/mailman/listinfo/python-list
Re: max(), sum(), next()
On Sat, 06 Sep 2008 00:33:25 -0400, Manu Hack wrote: Actually it's even more natural to state sum([x]) = x, and this way you can never conclude that sum([]) = 0 from there. But what you can say is that for any list L, sum(L) = sum(L + [0]). Therefore sum([]) = sum([] +[0]) = 0 -- Steven -- http://mail.python.org/mailman/listinfo/python-list
wxPython problem
I am trying to teach myself how to program in Python and use wxPython
for GUIs. I am using PyScripter, IDLE and EditPlus as my IDEs. I have
experienced an odd problem where I run a script once and it runs fine.
Run it again and I get an error and the script fails.
If the script is run directly from Python ('Run' from Windows Explorer)
or from EditPlus (in which I have a user-defined tool which calls
C:\Python25\pythonw.exe with the parameter of $(FileName)) then there is
*never* any error, no matter how many times the script is run.
Close down PyScripter or IDLE and then start either up again, load the
script and run it - it runs fine. Run it again and it fails. It seems
like something is already set in memory and cant be re-set (my lack of
knowledge is showing here :-( ).
More details are shown below. Any help or hints would be greatly
appreciated.
Regards,
Peter
RUNNING SIMPLE.PY (AND OTHER SCRIPTS USING WXPYTHON) FROM PYSCRIPTER I
GET THE FOLLOWING ERROR MESSAGE:
PyNoAppError: The wx.App object must be created first!
PyScripter loads a module (I presume from wxPython) called _windows.py
and highlights a particular line in red and displays the error message
from above. I have Googled the error message but the results have not
helped.
LISTING FOR SIMPLE.PY
#!/usr/bin/python
# simple.py
import wx
app = wx.App()
frame = wx.Frame(None, -1, 'simple.py')
frame.Show()
app.MainLoop()
EXERPT FROM _WINDOWS.PY - PYSCRIPTER HIGHLIGHTS SECOND LAST LINE
class Frame(TopLevelWindow):
Proxy of C++ Frame class
thisown = property(lambda x: x.this.own(), lambda x, v: x.this.own(v),
doc='The membership flag')
__repr__ = _swig_repr
def __init__(self, *args, **kwargs):
__init__(self, Window parent, int id=-1, String title=EmptyString,
Point pos=DefaultPosition, Size size=DefaultSize,
long style=DEFAULT_FRAME_STYLE, String name=FrameNameStr) - Frame
# The following line is highlighted as where the error occures
_windows_.Frame_swiginit(self,_windows_.new_Frame(*args, **kwargs))
self._setOORInfo(self)
RUNNING THE SIMPLE.PY SCRIPT FROM WITHIN IDLE PRODUCES THE FOLLOWING
ERROE MESSAGE:
Traceback (most recent call last):
File C:\Documents and Settings\Peter\My Documents\Dev\Python\WxPython
Tutorial\absolute.py, line 28, in module
Absolute(None, -1, '')
File C:\Documents and Settings\Peter\My Documents\Dev\Python\WxPython
Tutorial\absolute.py, line 9, in __init__
wx.Frame.__init__(self, parent, id, title, size=(250, 180))
File C:\Python25\Lib\site-packages\wx-2.8-msw-unicode\wx\_windows.py,
line 505, in __init__
_windows_.Frame_swiginit(self,_windows_.new_Frame(*args, **kwargs))
PyNoAppError: The wx.App object must be created first!
--
*Peter Anderson*
There is nothing more difficult to take in hand, more perilous to
conduct, or more uncertain in its success, than to take the lead in the
introduction of a new order of things—Niccolo Machiavelli, /The Prince/,
ch. 6
--
http://mail.python.org/mailman/listinfo/python-list
Re: max(), sum(), next()
On Sat, Sep 6, 2008 at 12:57 AM, castironpi [EMAIL PROTECTED] wrote: On Sep 5, 9:20 pm, Manu Hack [EMAIL PROTECTED] wrote: On Fri, Sep 5, 2008 at 1:04 PM, castironpi [EMAIL PROTECTED] wrote: On Sep 5, 3:28 am, Manu Hack [EMAIL PROTECTED] wrote: On Thu, Sep 4, 2008 at 4:25 PM, castironpi [EMAIL PROTECTED] wrote: On Sep 4, 2:42 pm, [EMAIL PROTECTED] wrote: David C. Ullrich: At least in mathematics, the sum of the elements of the empty set _is_ 0, while the maximum element of the empty set is undefined. What do you think about my idea of adding that 'default' argument to the max()/min() functions? Bye, bearophile For max and min, why can't you just add your argument to the set itself? The reason max([]) is undefined is that max( S ) is in S. It makes sense. The reason sum([]) is 0 is that sum( [ x ] ) - x = 0. It doesn't make sense to me. What do you set x to? For all x. But then how can you conclude sum([]) = 0 from there? It's way far from obvious. You can define sum([a1,a2,...,aN]) recursively as sum([a1,a2,...a(N-1)])+aN. Call the sum sum([a1,a2,...,aN]) X, then subtract aN. sum([a1,a2,...a(N-1)])+aN=X sum([a1,a2,...a(N-1)])+aN-aN=X-aN For N=2, we have: sum([a1,a2])=X sum([a1,a2])-a2=X-a2 sum([a1,a2])-a2-a1=X-a2-a1 Since X= a1+ a2, replace X. sum([a1,a2])-a2-a1=(a1+a2)-a2-a1 Or, sum([a1,a2])-a2-a1=0 Apply the recursive definition: sum([a1])+a2-a2-a1=0 And again: sum([])+a1+a2-a2-a1=0 And we have: sum([])=0. It makes more sense now, I just wanted to point out that only with sum([x]) = x, you can't get sum([]) = 0. -- http://mail.python.org/mailman/listinfo/python-list
Re: embed python in ms-word?
oyster wrote: In my ms-word documnet, there are some calculation whihc I have to change due to different argumnet. is there any way to embed python code in word, so that I can write the following as a macro or something else, then the result (i.e. 2) is shown in the word documnet? def f(n): if n2: return 1 else: return f(n-1)+f(n-2) main() return 'fib(3)=%0i' % f(3) if that is impossible, does there exist such word-addons can do that? thanx With Python and the win32 extensions you can write COM servers. These you can use from Visual Basic for Applications (VBA). But it's really only worth the effort if you're doing something less trivial than above ;-) -- Gerhard -- http://mail.python.org/mailman/listinfo/python-list
Re: wxPython problem
Peter Anderson wrote:
I am trying to teach myself how to program in Python and use wxPython
for GUIs. I am using PyScripter, IDLE and EditPlus as my IDEs. I have
experienced an odd problem where I run a script once and it runs fine.
Run it again and I get an error and the script fails.
If the script is run directly from Python ('Run' from Windows
Explorer) or from EditPlus (in which I have a user-defined tool
which calls C:\Python25\pythonw.exe with the parameter of $(FileName))
then there is *never* any error, no matter how many times the script
is run.
Close down PyScripter or IDLE and then start either up again, load the
script and run it - it runs fine. Run it again and it fails. It seems
like something is already set in memory and cant be re-set (my lack of
knowledge is showing here :-( ).
In PyScripter, you should run wxPython in the plain remote machine (not
the wxPython remote),
and you should set reset before run flag or reset the remote machine
each time yourself.
cheers,
Stef
More details are shown below. Any help or hints would be greatly
appreciated.
Regards,
Peter
RUNNING SIMPLE.PY (AND OTHER SCRIPTS USING WXPYTHON) FROM PYSCRIPTER I
GET THE FOLLOWING ERROR MESSAGE:
PyNoAppError: The wx.App object must be created first!
PyScripter loads a module (I presume from wxPython) called _windows.py
and highlights a particular line in red and displays the error message
from above. I have Googled the error message but the results have not
helped.
LISTING FOR SIMPLE.PY
#!/usr/bin/python
# simple.py
import wx
app = wx.App()
frame = wx.Frame(None, -1, 'simple.py')
frame.Show()
app.MainLoop()
EXERPT FROM _WINDOWS.PY - PYSCRIPTER HIGHLIGHTS SECOND LAST LINE
class Frame(TopLevelWindow):
Proxy of C++ Frame class
thisown = property(lambda x: x.this.own(), lambda x, v: x.this.own(v),
doc='The membership flag')
__repr__ = _swig_repr
def __init__(self, *args, **kwargs):
__init__(self, Window parent, int id=-1, String title=EmptyString,
Point pos=DefaultPosition, Size size=DefaultSize,
long style=DEFAULT_FRAME_STYLE, String name=FrameNameStr) - Frame
# The following line is highlighted as where the error occures
_windows_.Frame_swiginit(self,_windows_.new_Frame(*args, **kwargs))
self._setOORInfo(self)
RUNNING THE SIMPLE.PY SCRIPT FROM WITHIN IDLE PRODUCES THE FOLLOWING
ERROE MESSAGE:
Traceback (most recent call last):
File C:\Documents and Settings\Peter\My Documents\Dev\Python\WxPython
Tutorial\absolute.py, line 28, in module
Absolute(None, -1, '')
File C:\Documents and Settings\Peter\My Documents\Dev\Python\WxPython
Tutorial\absolute.py, line 9, in __init__
wx.Frame.__init__(self, parent, id, title, size=(250, 180))
File
C:\Python25\Lib\site-packages\wx-2.8-msw-unicode\wx\_windows.py,
line 505, in __init__
_windows_.Frame_swiginit(self,_windows_.new_Frame(*args, **kwargs))
PyNoAppError: The wx.App object must be created first!
--
http://mail.python.org/mailman/listinfo/python-list
Cancel instance create
Good day, I want MyClass to perform some tests and if them fail, I do not want instance to be created. But in code I wrote instance is created and also has parameters, that it should not have in case of tests failure. Is there a way to perform tests in MyClass.__init__ and set instance to None without any parameters? I do not want che code outside MyClass.__init__ to know anything about tests performed, and make decision to allow or prevent instance creation. The code I wrote is: ** class MyClass(): def __init__(self): self.param = spam Test = False if Test == True: print Creating instance... return else: print Instance creation not allowed... self = None return None a = MyClass() print a print a.param * Thanks, Aigars -- http://mail.python.org/mailman/listinfo/python-list
Re: use str as variable name
Marco Bizzarri wrote: Just a question: generic functions are not meant in the sense of generic functions of CLOS, am I right? it's meant in exactly that sense: len(L) means of all len() implementations available to the runtime, execute the most specific code we have for the object L. It is a generic functions like a CLOS one, as long as we remain to one parameter. I mean, there will be just one implemenatation of foo(bar, man) which the python interpretr can find; am I right? Let's see if I can sort this out without causing even more confusion. The Python *language* doesn't support generic functions in the CLOS sense, but a given Python *implementation* may use a dispatching machinery to select the best possible implementation for any call to a built-in function. Or in other words, the len() function shouldn't just be seen as a function that *always* does def len(L): return L.__len__() because if you look under the covers, it might be more like (using a hypothetical Python dialect): def generic len(L: list): return list::get_size(L) # fast internal dispatch def generic len(L: tuple): return tuple::get_size(L) # fast internal dispatch def generic len(L: object): return L.__len__() # fallback behaviour, using method dispatch where len represents a plurality of possible len implementations. How the dispatching is actually done is up to the specific Python implementation; CPython, for example, offers a slot mechanism for types implemented in C that's quite a bit faster than the method call machinery. And the slot mechanism isn't always single dispatch. For example, internal getattr(obj, name) calls use one of several slots, depending on what name is. Other Python implementations may use different approaches, but the point remains: a builtin function operation(a, b, c) isn't always mapped to a.__operation__(b, c) by the runtime; code that uses the latter form may be less efficient. And it's definitely less Pythonic. /F -- http://mail.python.org/mailman/listinfo/python-list
Re: Cancel instance create
Aigars Aigars wrote: I want MyClass to perform some tests and if them fail, I do not want instance to be created. But in code I wrote instance is created and also has parameters, that it should not have in case of tests failure. Is there a way to perform tests in MyClass.__init__ and set instance to None without any parameters? if you want construction to fail, raise an exception. ... def __init__(self): self.param = spam Test = False if Test: # please don't use explicit tests for truth print Creating instance... else: raise ValueError(some condition failed) (pick an exception class that matches the actual error, or create your own class if necessary) /F -- http://mail.python.org/mailman/listinfo/python-list
Re: Cancel instance create
ًWhat about no Constructor , and a custom instancing function that can return either None or the instance wanted -- http://mail.python.org/mailman/listinfo/python-list
Re: Cancel instance create
Mohamed Yousef schrieb: ًWhat about no Constructor , and a custom instancing function that can return either None or the instance wanted That doesn't solve the underlying problem - the instance is created. Just because it wasn't *returned*, doesn't mean it isn't there. Diez -- http://mail.python.org/mailman/listinfo/python-list
Re: Cancel instance create
I do not want code outside my class to perform tests and decide to create instance or not. Fredrik Lundh's advice to rise exception works perfectly. Thanks to all, Aigars Quoting Mohamed Yousef : #1611;What about no Constructor , and a custom instancing function that can return either None or the instance wanted -- http://mail.python.org/mailman/listinfo/python-list Links: -- [1] mailto:[EMAIL PROTECTED] -- http://mail.python.org/mailman/listinfo/python-list
Re: quake like multicoloured text
On Sep 5, 10:32 pm, Gabriel Genellina [EMAIL PROTECTED] wrote: En Fri, 05 Sep 2008 16:24:08 -0300, Durand [EMAIL PROTECTED] escribió: I'm wondering how I could render text with PIL in which different parts of the text are different characters. This is for a game stats script where names are written like: ^1Red ^2Green ^3Yellow, etc. The problem is that I currently use text in the ImageDraw module but the only way I can think of rendering text is by rendering each bit of text in a separate colour. Example: draw.text((0,0),Red, fill=red) draw.text((30,0),Green, fill=green) draw.text((60,0),Yellow, fill=green) except that I'm not sure how much spacing there is between each coloured bit of text(30px is assumed in the example)...Would there be an alternate method of doing this? You could use the draw.textsize method to measure how much space will take each part... -- Gabriel Genellina Thanks, I guess I should have done more research... -- http://mail.python.org/mailman/listinfo/python-list
Re: max(), sum(), next()
castironpi wrote:
On Sep 5, 9:20 pm, Manu Hack [EMAIL PROTECTED] wrote:
On Fri, Sep 5, 2008 at 1:04 PM, castironpi [EMAIL PROTECTED] wrote:
On Sep 5, 3:28 am, Manu Hack [EMAIL PROTECTED] wrote:
On Thu, Sep 4, 2008 at 4:25 PM, castironpi [EMAIL PROTECTED] wrote:
On Sep 4, 2:42 pm, [EMAIL PROTECTED] wrote:
David C. Ullrich:
At least in mathematics, the sum of the elements of
the empty set _is_ 0, while the maximum element of the
empty set is undefined.
What do you think about my idea of adding that 'default' argument to
the max()/min() functions?
Bye,
bearophile
For max and min, why can't you just add your argument to the set
itself?
The reason max([]) is undefined is that max( S ) is in S.
It makes sense.
The reason sum([]) is 0 is that sum( [ x ] ) - x = 0.
It doesn't make sense to me. What do you set x to?
For all x.
But then how can you conclude sum([]) = 0 from there? It's way far
from obvious.
You can define sum([a1,a2,...,aN]) recursively as
sum([a1,a2,...a(N-1)])+aN. Call the sum sum([a1,a2,...,aN]) X, then
subtract aN.
sum([a1,a2,...a(N-1)])+aN=X
sum([a1,a2,...a(N-1)])+aN-aN=X-aN
For N=2, we have:
sum([a1,a2])=X
sum([a1,a2])-a2=X-a2
sum([a1,a2])-a2-a1=X-a2-a1
Since X= a1+ a2, replace X.
sum([a1,a2])-a2-a1=(a1+a2)-a2-a1
Or,
sum([a1,a2])-a2-a1=0
Apply the recursive definition:
sum([a1])+a2-a2-a1=0
And again:
sum([])+a1+a2-a2-a1=0
And we have:
sum([])=0.
This is not necessarily so.
The flaw is that you provide a recursive definition with no start value,
which is to say it is not a recursive definition at all.
A recursive definition should be (for lists where elements
can be added, and ignoring pythonic negative indexing):
Define 'sum(L)' by
a. sum(L[0]) = L[0]
b. sum(L[0:i]) = sum(L[0:i-1]) + L[i] ... if i 0
From this you can prove the reverse recursion
sum{L[0:k]) = sum(L[0:k+1]) - L[k+1]
__only__ if k = 0
It says nothing about the empty list.
You could add, as part of the definition, that sum{[]) = 0, or any other
value.
A rather different approach, not quite simple recursion, would be to
start with
A. a slicing axiom, something like:
for all non-negative integers, a,b,c with a =b = c:
sum(L[a:c]) = sum(L[a:b]) + sum(L[b:c])
B. a singleton axiom:
for all integers a where L[a] exists:
sum(L[a:a]) = L[a]
2a. sum{
--
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Re: max(), sum(), next()
castironpi wrote:
On Sep 5, 9:20 pm, Manu Hack [EMAIL PROTECTED] wrote:
On Fri, Sep 5, 2008 at 1:04 PM, castironpi [EMAIL PROTECTED] wrote:
On Sep 5, 3:28 am, Manu Hack [EMAIL PROTECTED] wrote:
On Thu, Sep 4, 2008 at 4:25 PM, castironpi [EMAIL PROTECTED] wrote:
On Sep 4, 2:42 pm, [EMAIL PROTECTED] wrote:
David C. Ullrich:
At least in mathematics, the sum of the elements of
the empty set _is_ 0, while the maximum element of the
empty set is undefined.
What do you think about my idea of adding that 'default' argument to
the max()/min() functions?
Bye,
bearophile
For max and min, why can't you just add your argument to the set
itself?
The reason max([]) is undefined is that max( S ) is in S.
It makes sense.
The reason sum([]) is 0 is that sum( [ x ] ) - x = 0.
It doesn't make sense to me. What do you set x to?
For all x.
But then how can you conclude sum([]) = 0 from there? It's way far
from obvious.
You can define sum([a1,a2,...,aN]) recursively as
sum([a1,a2,...a(N-1)])+aN. Call the sum sum([a1,a2,...,aN]) X, then
subtract aN.
sum([a1,a2,...a(N-1)])+aN=X
sum([a1,a2,...a(N-1)])+aN-aN=X-aN
For N=2, we have:
sum([a1,a2])=X
sum([a1,a2])-a2=X-a2
sum([a1,a2])-a2-a1=X-a2-a1
Since X= a1+ a2, replace X.
sum([a1,a2])-a2-a1=(a1+a2)-a2-a1
Or,
sum([a1,a2])-a2-a1=0
Apply the recursive definition:
sum([a1])+a2-a2-a1=0
And again:
sum([])+a1+a2-a2-a1=0
And we have:
sum([])=0.
This is not necessarily so.
The flaw is that you provide a recursive definition with no start value,
which is to say it is not a recursive definition at all.
A recursive definition should be (for lists where elements
can be added, and ignoring pythonic negative indexing):
Define 'sum(L)' by
a. sum(L[0:1]) = L[0]
b. sum(L[0:i]) = sum(L[0:i-1]) + L[i] ... if i 1
From this you can prove the reverse recursion
sum{L[0:k]) = sum(L[0:k+1]) - L[k+1]
__only__ if k = 0
It says nothing about the empty list.
You could add, as part of the definition, that sum{[]) = 0, or any other
value.
A rather different approach, not quite simple recursion, would be to
start with
A. a slicing axiom, something like:
for all non-negative integers, a,b,c with a =b = c:
sum(L[a:c]) = sum(L[a:b]) + sum(L[b:c])
B. a singleton axiom:
for all integers a where L[a] exists:
sum(L[a:a]) = L[a]
2a. sum{
--
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Re: embed python in ms-word?
in fact, during my work, I often write documnets in ms-word. But the doc has many numbers in it, which need to be calculated and to be modified frequently. Is there a method to write a ms-word add-in, so that 1.I can type in the calculation steps in some program language, please have a look at http://blender.bokee.com/inc/word_add_in1.jpg 2.then the result (here, it is 8) is shown in the doc when I close this window? please have a look at http://blender.bokee.com/inc/word_add_in2.jpg 3.when I double-click the result 8, I can view/edit the code again 4.the code for calculation is stored in DOC file too, I can change it later mathtype equation is a kind of such thing, but only for displaying nice equation I don't think vba is a good answer, the main reason is: the vba code has an incompact link with its result in the documnet -- http://mail.python.org/mailman/listinfo/python-list
Re: why is self not passed to id()? solution
I found following solution to the problem.
Instead of assigning id directly to __hash__ it has to be wrapped with an
instancemethod object. It is somehow strange that this doesn't happen
automatically and it is also strange that instancemethod isn't exposed in
the type module. However it can easily be done and is speeding things up
by almost an factor of 2.
Thank's again for all the help.
Rüdiger
**
class foo(list):
__hash__ = lambda x: id(x)
instancemethod = type(foo.__hash__)
class bar(list):
pass
bar.__hash__ = instancemethod(id, None, bar)
def test0( obj ):
_s_ = set()
_s_add = _s_.add
_s_pop = _s_.pop
for _i_ in xrange(100):
_s_add(obj())
_s_pop()
def test1():
return test0(foo)
def test2():
return test0(bar)
if __name__ == '__main__':
test1()
test2()
pass
**
python -m cProfile test01.py
610 function calls in 30.547 CPU seconds
Ordered by: standard name
ncalls tottime percall cumtime percall filename:lineno(function)
10.0000.000 30.547 30.547 string:1(module)
10.0000.000 30.547 30.547 test01.py:1(module)
10.0000.0000.0000.000 test01.py:1(foo)
2 10.7845.392 30.547 15.273 test01.py:10(test0)
10.0000.000 19.543 19.543 test01.py:18(test1)
1004.5540.0006.7000.000 test01.py:2(lambda)
10.0000.000 11.003 11.003 test01.py:20(test2)
10.0000.0000.0000.000 test01.py:6(bar)
10.0010.001 30.547 30.547 {execfile}
1002.1460.0002.1460.000 {id}
2008.6260.000 15.3270.000 {method 'add' of 'set'objects}
2004.4360.0004.4360.000 {method 'pop' of 'set'objects}
--
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Re: embed python in ms-word?
oyster schrieb: in fact, during my work, I often write documnets in ms-word. But the doc has many numbers in it, which need to be calculated and to be modified frequently. Is there a method to write a ms-word add-in, so that 1.I can type in the calculation steps in some program language, please have a look at http://blender.bokee.com/inc/word_add_in1.jpg 2.then the result (here, it is 8) is shown in the doc when I close this window? please have a look at http://blender.bokee.com/inc/word_add_in2.jpg 3.when I double-click the result 8, I can view/edit the code again 4.the code for calculation is stored in DOC file too, I can change it later mathtype equation is a kind of such thing, but only for displaying nice equation I don't think vba is a good answer, the main reason is: the vba code has an incompact link with its result in the documnet I don't know what you mean with the last sentence - but I still think VBA is the answer. There is no other way to write a plugin or some such for word than using COM, and VB *is* COM. So whatever you can do in Word, it's exposed in VBA. Bringing python into the mixture is just creating a lot of hassle. Automating word with Python is a different thing - that seems to be popular and powerful. Diez -- http://mail.python.org/mailman/listinfo/python-list
Re: running python as a dameon
On Sep 5, 9:56 pm, Sean Davis [EMAIL PROTECTED] wrote: What I want to do is to provide the python NLP program as a service to any other PHP/Java/Ruby process request. So the mapping is http - apache - PHP/Java/Ruby/... - Python NLP Why not use a simple CGI script or wsgi application? You could make the service online and interactive and with the same application and code make an XMLRPC web service. So, things would look more like: http - apache - Python (running NLP and serving requests) You can use apache to proxy requests to any one of a dozen or so python-based webservers. You could also use mod_wsgi to interface with a wsgi application. Sean xmlrpc is the right idea, as it interfaces easily across languages. -- http://mail.python.org/mailman/listinfo/python-list
How to bring subprocess to the foreground?
Hi, I've a batch file that I open with the subprocess .Popen() . When this batch file is run I want to bring it to the foreground. Please suggest how can I do this? Regards, Rajat -- http://mail.python.org/mailman/listinfo/python-list
Re: How to bring subprocess to the foreground?
[EMAIL PROTECTED] schrieb: Hi, I've a batch file that I open with the subprocess .Popen() . When this batch file is run I want to bring it to the foreground. Please suggest how can I do this? You can't. You can capture the stdout using the pipe-arguments, and in your main-process, read that and write it to the main process' stdout. Diez -- http://mail.python.org/mailman/listinfo/python-list
Re: wxPython problem
Stef Mientki said: In PyScripter, you should run wxPython in the plain
remote machine (not the wxPython remote),and you should set reset
before run flag or reset the remote machine each time yourself.
Stef,
Thanks for the help! It has taken several hours to find and install the
correct version of Rpyc (which is required to run the remote Python
engine but it now seems to be working fine. And the Reinitialise the
Python engine {Alt]+[F2] does need to be done between script runs.
Given all that, the script now runs multiple times in PyScripter. The
script still only runs ONCE in IDLE but I can live with that.
In case others find this message from a search; I am using Python 2.5.2
and it requires rpyc-2.60.zip from the Rpyc download page (see
http://rpyc.wikispaces.com/ click on the Download link and make sure
you select the main link under the Packages column at Sourceforge.
You will be shown a list of Rpyc versions. For Python 2.5.2 choose
Relese 2.60. This will save you the several hours its cost me.
Thanks again Stef.
Regards,
Peter
--
Peter Anderson
There is nothing more difficult to take in hand, more perilous to
conduct, or more uncertain in its success, than to take the lead in the
introduction of a new order of things—Niccolo Machiavelli, /The Prince/,
ch. 6
--
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Re: max(), sum(), next()
Steven D'Aprano wrote: On Sat, 06 Sep 2008 00:33:25 -0400, Manu Hack wrote: Actually it's even more natural to state sum([x]) = x, and this way you can never conclude that sum([]) = 0 from there. But what you can say is that for any list L, sum(L) = sum(L + [0]). Therefore sum([]) = sum([] +[0]) = 0 Yep. The way it is preserves the distributive property sum(a+b) = sum(a) + sum(b) This would matter in cases like (untested code..) suvsales = sum (sum (s.price for s in d.sales if s.class='suv') for d in districts) Mel. -- http://mail.python.org/mailman/listinfo/python-list
Canonical way to build Python 2.6/svn on MacIntel/MacOSX10.5 with icc 32bits 10.1.014
Hi, I would like to build Python (svn) on Macosx 10.5 with icc in /opt/intel/cc (32 bit). Can you help me to determine the right way to do this ? I got a prototype with: export CC=icc export CXX=icpc export CFLAGS=-w ./configure --with-framework-name=PythonIntel 1) It seems to be unsufficient. Does someone have links/mail archives/patches/scripts ? 2) Python needs gettext for _locale package, but I fail to compile it with icc. 3) How can I build an autonomous and sufficient distribution (a dmg file with everything in it) ? Thanks, Mathieu -- http://mail.python.org/mailman/listinfo/python-list
Re: How to bring subprocess to the foreground?
On Sat, Sep 6, 2008 at 3:13 PM, Diez B. Roggisch [EMAIL PROTECTED] wrote: [EMAIL PROTECTED] schrieb: Hi, I've a batch file that I open with the subprocess .Popen() . When this batch file is run I want to bring it to the foreground. Please suggest how can I do this? You can't. You can capture the stdout using the pipe-arguments, and in your main-process, read that and write it to the main process' stdout. Diez -- http://mail.python.org/mailman/listinfo/python-list Hi Diez, Thanks for the information. That's valuable information. I though of displayin an information message on the screen through tkMessageBox while the subprocess is running, I did it using: try: testing = subprocess.Popen([batchFilePath], \ shell = True) retCode = testing.wait() tkMessageBox._show(Test Harness execution, \ icon = 'info', \ message=Testing %s in progress... % libName) except: tkMessageBox._show(Error, \ type='ok', icon='error', \ message=Error executing %s Test Harness % libName) return None else: print retCode But the message is never displayed. Please suggest if there is something wrong with this code -- Regards, Rajat -- http://mail.python.org/mailman/listinfo/python-list
[matplotlib] Overlapping axis text
I got a really annoying problem with datetime graphs. The problem is
that with a long range time graph, the text on the x axis keeps
overlapping like here: http://durand.zephyrhosting.net/tremcs/graph_all.png
Would there be any way to fix this? I was thinking of rotating the
text so that there was enough space for each one but the best solution
would be to only display text with the right scale. IE, with a 7 day
graph, each day would have text, with a year long graph, each month
would be displayed, etc...
This is the code I use at the moment but its pretty messy:
import dateutil,pylab
from matplotlib.dates import MonthLocator, WeekdayLocator
fig = pylab.figure()
ax = fig.add_subplot(111)
days= MonthLocator() # every monday
months = MonthLocator() # every month
ax.xaxis.set_major_locator(months)
ax.xaxis.set_minor_locator(days)
pylab.plot_date(pylab.date2num(dates), allkills, '.-', color='blue')
pylab.plot_date(pylab.date2num(dates), alldeaths, '.-',
color='red')
pylab.plot_date(pylab.date2num(dates), kills, '.-',
color='darkgreen')
pylab.plot_date(pylab.date2num(dates), deaths, '.-',
color='orange')
if legend == 1:
pylab.legend((Total Kills,Total Deaths, Single
Session Kills, Single Session Deaths), 'lower left')
pylab.xlabel('Date')
pylab.ylabel('Stats')
ax2 = pylab.twinx()
pylab.plot_date(pylab.date2num(dates), allratio, '.-',
color='purple')
pylab.plot_date(pylab.date2num(dates), ratio, '.-',
color='yellow')
pylab.ylabel('Ratio')
ax2.yaxis.tick_right()
pylab.show()
Please excuse the extra tabbing, it's part of an if statement.
--
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Re: Overlapping axis text
Err...made a mistake there. days= WeekdayLocator() # every monday months = MonthLocator() # every month That doesn't change my question though. Thanks -- http://mail.python.org/mailman/listinfo/python-list
Calling global functions from a class?
HI, I have the following python script: def __normalizePath( path ): return osp.abspath( osp.normpath( path ) ) class AbsolutePath: def __init__( self, root= ): _root = __normalizePath( root ) When I create an AbsolutePath object, I get the following error: NameError: global name '_AbsolutePath__normalizePath' is not defined Is there a reason for this? How can I make this work? -- http://mail.python.org/mailman/listinfo/python-list
Want to display a message box while subprocess is running
Hi, I m using subprocess module and using the Popen call. While the subprocess if running, I want to display a tkMessageBox(). Does some one has a sample code for this? Thanks and regards, Rajat -- http://mail.python.org/mailman/listinfo/python-list
Re: Calling global functions from a class?
Robert Dailey wrote: I have the following python script: def __normalizePath( path ): return osp.abspath( osp.normpath( path ) ) class AbsolutePath: def __init__( self, root= ): _root = __normalizePath( root ) When I create an AbsolutePath object, I get the following error: NameError: global name '_AbsolutePath__normalizePath' is not defined Is there a reason for this? the __ prefix (double underscores) is reserved for private attributes and methods in a class. it does not work for module-level names. How can I make this work? rename the global function. /F -- http://mail.python.org/mailman/listinfo/python-list
Failure in building ctypes with intel icc
Hi, I got this error in compilation, and I don't know how to solve it: *** WARNING: renaming _ctypes since importing it failed: dlopen(build/lib.macosx-10.3-i386-2.6/_ctypes.so, 2): Symbol not found: ___builtin_dwarf_cfa Referenced from: /Users/mathieuprevot/svn/python/build/lib.macosx-10.3-i386-2.6/_ctypes.so Expected in: dynamic lookup Any hints ? thanks, Mathieu -- http://mail.python.org/mailman/listinfo/python-list
Re: Cancel instance create
Fredrik Lundh wrote: Aigars Aigars wrote: I want MyClass to perform some tests and if them fail, I do not want instance to be created. If you do not want the instance created at all, you would have to write a custom .__new__ method, but that is tricky, something I would have to look up how to do, and most likely not needed. Fredrik's solution below is much easier and the one I would use if at all possible. But in code I wrote instance is created and also has parameters, that it should not have in case of tests failure. Is there a way to perform tests in MyClass.__init__ and set instance to None without any parameters? if you want construction to fail, raise an exception. ... def __init__(self): At this point, you have an instance of your class bound to local name 'self'. Usually, its only individual attributes are (in 3.0, anyway, as far as I can tell) .__class__ and an empty .__dict__. Of course, it inherits class and superclass attributes, but it is otherwise blank. (The main exception would be if you were inheriting from an immutable class that set attributes in .__new__, but then you would not be writing .__init__.) self.param = spam Test = False if Test: # please don't use explicit tests for truth print Creating instance... else: raise ValueError(some condition failed) (pick an exception class that matches the actual error, or create your own class if necessary) Once the exception gets disposed of (if not before), the blank instance gets unbound from 'self' and since it does not get bound to anything else, it becomes eligible for garbage collection. tjr -- http://mail.python.org/mailman/listinfo/python-list
Re: How to bring subprocess to the foreground?
On 6 Sep, 17:58, [EMAIL PROTECTED] wrote: I though of displayin an information message on the screen through tkMessageBox while the subprocess is running, I did it using: try: testing = subprocess.Popen([batchFilePath], \ shell = True) retCode = testing.wait() Note that you wait for the process to finish here... tkMessageBox._show(Test Harness execution, \ icon = 'info', \ message=Testing %s in progress... % libName) ...and that you show a message about the process running *after* waiting until it isn't running any more. except: tkMessageBox._show(Error, \ type='ok', icon='error', \ message=Error executing %s Test Harness % libName) return None else: print retCode But the message is never displayed. Please suggest if there is something wrong with this code I think you should first show your message, *then* wait for the process to finish. Paul -- http://mail.python.org/mailman/listinfo/python-list
Re: why is self not passed to id()? solution
Ruediger wrote:
I found following solution to the problem.
Instead of assigning id directly to __hash__ it has to be wrapped with an
instancemethod object. It is somehow strange that this doesn't happen
automatically and it is also strange that instancemethod isn't exposed in
the type module.
There are several internal implementation types not exposed in types
because they are subject to change from version to version In 3.0, your
code does not work. Instancemethod may to added to 3.0 or 3.1 as a
built-in function.
**
class foo(list):
__hash__ = lambda x: id(x)
type
instancemethod = type(foo.__hash__)
In 2.x, this gives you 'instancemethod'. In 3.0, you get 'function' as
unbound methods are no longer wrapped when the underlying function is a
'function' (resulting from def or lambda abbreviation).
class bar(list):
pass
bar.__hash__ = instancemethod(id, None, bar)
Calling a 'function' with those parameters will not work.
Did you miss the following from my previous response?
There *is* a third alternative, which works in this case, and which
should be closer in speed to id. I will leave you to do a speed test.
class bang(list):
__hash__ = object.__hash__
s=set()
s.add(bang())
s
{[]}
__eq__ = object.__eq__ should also work instead of the Python
implementation I gave in my response to another response.
I would expect the already-wrapped id should work in 2.x also.
Terry Jan Reedy
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Re: max(), sum(), next()
On Sep 5, 10:45�pm, Steven D'Aprano [EMAIL PROTECTED] cybersource.com.au wrote: On Fri, 05 Sep 2008 22:20:06 -0400, Manu Hack wrote: On Fri, Sep 5, 2008 at 1:04 PM, castironpi [EMAIL PROTECTED] wrote: snip [The rest of this is (mostly) aimed at Mensanator, Ok, I see where you're coming from. Fundamentally, the abstract function sum and the concrete Python implementation of sum() are both human constructs. It's not like there is some pure Platonic[1] Ideal Sum floating in space that we can refer to. Somewhere, sometime, some mathematician had to *define* sum(), and other mathematicians had to agree to use the same definition. They could have decided that sum must take at least two arguments, because addition requires two arguments and it's meaningless to talk about adding a single number without talking about adding it to something else. But they didn't. Ok. But the problem is they DID in SQL: x + Null = Null. Earlier, you said that an empty box contains 0 widgets. Fine, empty means 0. But Null doesn't mean empty. Say your widget supplier just delivers a box and you haven't opened it yet. Is the box likely to be empty? Probably not, or they wouldn't have shipped it. In this case, Null means unknown, not 0. The number of widgets you have on hand is Null (unknown) because inventory + Null = Null. SQL will correctly tell you that the amount on hand is unknown, whereas Python will tell you the amount on hand is inventory, which is incorrect. Similarly, they might have decided that sum must take at least one argument, and therefore prohibit sum([]), but they didn't: it's more useful for sum of the empty list to give zero than it is for it to be an error. As I mentioned earlier, mathematicians are nothing if not pragmatists. Here's a real world example (no ivory tower stuff): An oil refinery client has just excavated a big pile of dirt to lay a new pipeline. Due to the volume of the pipe, there's dirt left over. Ideally, the client would like to use that dirt as landfill (free), but it must be tested for HAPS (by summing the concentrations of organic constituents) to see whether it is considered hazardous waste, it which cas it must be taken off site and incinerated (costly). In MOST cases, a HAPS sum of 0 would be illegal because 0's generally cannot be reported in analytical tests, you can't report a result less than it's legal reporting limit. If ALL the consituents were undetected, the sum should be that of the sum of the reporting limits, thus, it cannot be 0. Can't I just use a sum of 0 to tell me when data is missing? No, because in some cases the reporting limit of undetected compounds is set to 0. In which case, a 0 HAPS score means we can confidently reccomend that the dirt is clean and can be freely reused. But if the analysis information is missing (hasn'r arrived yet or still pending validation) we WANT the result to be UNKNOWN so that we don't reccomend to the client that he take an illegal course of action. In this case, SQL does the correct thing and Python would return a false result. -- Steven -- http://mail.python.org/mailman/listinfo/python-list
Re: How to bring subprocess to the foreground?
On Sat, Sep 6, 2008 at 6:53 PM, Paul Boddie [EMAIL PROTECTED] wrote: On 6 Sep, 17:58, [EMAIL PROTECTED] wrote: I though of displayin an information message on the screen through tkMessageBox while the subprocess is running, I did it using: try: testing = subprocess.Popen([batchFilePath], \ shell = True) retCode = testing.wait() Note that you wait for the process to finish here... tkMessageBox._show(Test Harness execution, \ icon = 'info', \ message=Testing %s in progress... % libName) ...and that you show a message about the process running *after* waiting until it isn't running any more. except: tkMessageBox._show(Error, \ type='ok', icon='error', \ message=Error executing %s Test Harness % libName) return None else: print retCode But the message is never displayed. Please suggest if there is something wrong with this code I think you should first show your message, *then* wait for the process to finish. Paul -- http://mail.python.org/mailman/listinfo/python-list Such a silly mistake I'm committing. Thanks a ton. -- Regrads, Rajat -- http://mail.python.org/mailman/listinfo/python-list
How to run PyOS_InputHook from python code (i.e. yield to event loops)
Background: PyOS_InputHook is something that gets run when python is
doing raw_input. TkInter and friends use it to run their event loops,
so that their events are handled while python is doing raw_input.
What I'd like to do is run the same function without having to do
raw_input. I.e. I'd like to run whatever event loop is available,
without incorporating any gui-specific code (PyOS_InputHook seems like
a nifty way to accomplish this).
My actual use case is to keep a tkinter application responsive while
launching a background process (and waiting for it to complete!).
My eventual code would be something like:
launch_process_in_thread('bzr pull')
while not is_done:
pyos_inputhook()
time.sleep(0.1)
print Done!
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Re: running python as a dameon
On 6 sep, 15:44, Michael Palmer [EMAIL PROTECTED] wrote: On Sep 5, 9:56 pm, Sean Davis [EMAIL PROTECTED] wrote: What I want to do is to provide the python NLP program as a service to any other PHP/Java/Ruby process request. So the mapping is http - apache - PHP/Java/Ruby/... - Python NLP Why not use a simple CGI script or wsgi application? You could make the service online and interactive and with the same application and code make an XMLRPC web service. So, things would look more like: http - apache - Python (running NLP and serving requests) You can use apache to proxy requests to any one of a dozen or so python-based webservers. You could also use mod_wsgi to interface with a wsgi application. Sean xmlrpc is the right idea, as it interfaces easily across languages. I just daemonize some utility script these week. For that I took one of the scripts in the ASPN python cookbook : google those 3 words then search python and you will find out your solution faster than I end up this mail. It worked like a charm on my linux box. BTW, I wouldn't complicate with xml stuffs if you don't need it. Good luck. -- http://mail.python.org/mailman/listinfo/python-list
Re: List of modules available for import inside Python?
Michele Simionato wrote: On Aug 28, 6:21 am, ssecorp [EMAIL PROTECTED] wrote: Is there a way to view all the modules I have available for import from within Python? Like writing in the interpreter: Try: help() help modules Please wait a moment while I gather a list of all available modules... snip This looks like it could be a useful tool, but when I try it I get the following: Please wait a moment while I gather a list of all available modules... /usr/lib/python2.5/site-packages/reportlab/lib/PyFontify.py:35: Warning: 'with' will become a reserved keyword in Python 2.6 /usr/lib/python2.5/site-packages/reportlab/lib/PyFontify.py:36: Warning: 'with' will become a reserved keyword in Python 2.6 Traceback (most recent call last): File stdin, line 1, in module File /usr/lib/python2.5/site.py, line 346, in __call__ return pydoc.help(*args, **kwds) File /usr/lib/python2.5/pydoc.py, line 1645, in __call__ self.interact() File /usr/lib/python2.5/pydoc.py, line 1663, in interact self.help(request) File /usr/lib/python2.5/pydoc.py, line 1679, in help elif request == 'modules': self.listmodules() File /usr/lib/python2.5/pydoc.py, line 1797, in listmodules ModuleScanner().run(callback) File /usr/lib/python2.5/pydoc.py, line 1848, in run for importer, modname, ispkg in pkgutil.walk_packages(): File /usr/lib/python2.5/pkgutil.py, line 110, in walk_packages __import__(name) File /usr/local/lib/python2.5/site-packages/PIL/__init__.py, line 1342, in module File /usr/local/lib/python2.5/site-packages/PIL/__init__.py, line 927, in main UnboundLocalError: local variable 'given_files' referenced before assignment which could be because I am fairly free and unrestrained when it comes to installing stuff, and I see now I have modules on both /usr/lib/python2.5 and /usr/local/lib/python2.5 Apparently python knows about them both, but I don't know I haven't introduced an incompatibility somewhere...and that PIL package showing up at the tail of the errors was one of my more recent additions... Any help will be appreciated, sc -- http://mail.python.org/mailman/listinfo/python-list
Re: running python as a dameon
On 6 sep, 22:16, kaer [EMAIL PROTECTED] wrote: On 6 sep, 15:44, Michael Palmer [EMAIL PROTECTED] wrote: On Sep 5, 9:56 pm, Sean Davis [EMAIL PROTECTED] wrote: What I want to do is to provide the python NLP program as a service to any other PHP/Java/Ruby process request. So the mapping is http - apache - PHP/Java/Ruby/... - Python NLP Why not use a simple CGI script or wsgi application? You could make the service online and interactive and with the same application and code make an XMLRPC web service. So, things would look more like: http - apache - Python (running NLP and serving requests) You can use apache to proxy requests to any one of a dozen or so python-based webservers. You could also use mod_wsgi to interface with a wsgi application. Sean xmlrpc is the right idea, as it interfaces easily across languages. I just daemonize some utility script these week. For that I took one of the scripts in the ASPN python cookbook : google those 3 words then search python and you will find out your solution faster than I end up this mail. It worked like a charm on my linux box. BTW, I wouldn't complicate with xml stuffs if you don't need it. Good luck. you obviously search daemon not search python. Her is the link: http://www.google.com/search?q=daemonhl=enie=UTF-8btnG=Google%2BSearchqdr=allocct=anydt=isitesearch=code.activestate.com -- http://mail.python.org/mailman/listinfo/python-list
How to merge a module into a package w/ distutils?
The bsddb module is on the way out (deprecated in 2.6, gone in 3.0). That leaves Python without a cross-platform dbm module to sit underneath anydbm and shelve. I figured it might be useful to base something on top of sqlite3, which is cross-platform. The result is available in the Python sandbox: http://svn.python.org/view/sandbox/trunk/dbm_sqlite/ There are three files, a dbm.sqlite module, a test case and a modified bit of dbm documentation. For testing I'd like to install this in such a way that I can simply import dbm.sqlite but not overwrite the core install. I'd also not like to lose dbm.gdbm, etc during this testing phase. Is there some way to do this with distutils? Ideally, I'd like there to be a dbm package in site-packages but which falls back to the central installation when, say, dbm.gdbm isn't found. Thx, Skip -- http://mail.python.org/mailman/listinfo/python-list
String/Number Conversion
Hello Folks!
I've got a little problem here, which which really creeps me out at the
moment.
I've got some strings, which only contain numbers plus eventually one
character as si-postfix (k for kilo, m for mega, g for giga). I'm trying
to convert those strings to integers, with this function:
def eliminate_postfix(value):
if type(value) is str:
value.upper()
if value.endswith('K'):
mult = 1000
elif value.endswith('M'):
mult = 100
elif value.endswith('G'):
mult = 10
else:
mult = 1
if mult is 1:
value = string.atoi(value)
else:
value = string.atoi(value[:-1]) * mult
return value
The problem is as follows: Everytime a string with a postfix should get
converted, mult does not get set properly. It is always 1. Does anyone
have an idea how to fix this? I just don't see it, maybe because I'm
pretty new to python or because I'm just blind I would be really greatful.
Kind regards,
Andy
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Re: String/Number Conversion
On Sep 6, 5:04 pm, Andreas Hofmann [EMAIL PROTECTED]
wrote:
Hello Folks!
I've got a little problem here, which which really creeps me out at the
moment.
I've got some strings, which only contain numbers plus eventually one
character as si-postfix (k for kilo, m for mega, g for giga). I'm trying
to convert those strings to integers, with this function:
def eliminate_postfix(value):
if type(value) is str:
value.upper()
if value.endswith('K'):
mult = 1000
elif value.endswith('M'):
mult = 100
elif value.endswith('G'):
mult = 10
else:
mult = 1
if mult is 1:
value = string.atoi(value)
else:
value = string.atoi(value[:-1]) * mult
return value
The problem is as follows: Everytime a string with a postfix should get
converted, mult does not get set properly. It is always 1. Does anyone
have an idea how to fix this? I just don't see it, maybe because I'm
pretty new to python or because I'm just blind I would be really greatful.
Kind regards,
Andy
Hello,
1. You call value.upper(), but you do not capture the results of that
method. Strings are immutable in Python.
value = value.upper()
2. You should use == instead of is in the comparison of mult being
1.
if mult == 1:
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Re: How to write verbose scripts
On Sep 3, 6:31 pm, Uwe Schmitt [EMAIL PROTECTED] wrote: On 2 Sep., 18:55, Steven D'Aprano [EMAIL PROTECTED] cybersource.com.au wrote: I find myself writing command line tools in Python where I wish to include verbose output to stdout. I start with a helper function: def print_(obj, level=0): if _verbosity = level: print obj And then I end up with functions or methods looking like this: def parrot(x) print_(precondition, level=2) do_something() print_(status is good..., level=1) print_(parrot is squawking strongly now, level=2) do_something_else() print_(squawk squawk squawk, level=3) do_more() print_(postcondition, level=1) return something That often means that my functions end up with more message printing code than actual code. The whole thing seems messy and hard to manage for all but the smallest scripts. Worst of all, sometimes the messages I wish to print may be expensive to compute, and I don't want to waste time computing them if they aren't going to be printed because the verbosity is too low. But nor do I wish to fill my code with this: if _verbosity = 3: x = calculate_complicated_thing() print_(x, level=3) Is there a better way of doing this than the way I am going about it? -- Steven You can save some code if you use function decorators for logging input and output values of functions. So write lots of functions containing one statement and your problem is solved ;-) Greetings, Uwe That would be perfect if python is a fully functional language (read that as: purely functional language). Functional language dictates no side effects, so logging input and output of functions is pretty much everything needed to do debugging (which is the main reason for having verbose mode). It would still be feasible, though, if you keep yourself from using functions with side-effects (or use as few of them as possible). Bjorn Lindqvist says: One big downside with that approach is that it becomes much harder to grep for the log message. Usually when I go through logs, I don't care what exactly the message says, just that it is easily googleable (uses some kind of identifying text) and that it is unique so I can know exactly where it was emitted. Actually, I'd prefer a log code (perhaps also as an option, to use -e for showing up log code besides the log message). The log code would be unique and referenced only once in the whole application (to nail down who said what to a single point). The code would make a call to the log printer with the log code (not the error string) and a few arguments to be interpolated to the error string (taken from a dictionary indexed by error code). The downside is loss of inline documentation by the logging codes. -- http://mail.python.org/mailman/listinfo/python-list
Re: String/Number Conversion
On Sat, 06 Sep 2008 23:04:14 +0200, Andreas Hofmann wrote: Hi, I've got a little problem here, which which really creeps me out at the moment. I've got some strings, which only contain numbers plus eventually one character as si-postfix (k for kilo, m for mega, g for giga). I'm trying to convert those strings to integers, with this function: if mult is 1: ^^ You're testing for identity, not for equality. Change it to if mult == 1. Is it alright now? -- Regards, Wojtek Walczak, http://tosh.pl/gminick/ -- http://mail.python.org/mailman/listinfo/python-list
Re: String/Number Conversion
On Sep 7, 7:04 am, Andreas Hofmann [EMAIL PROTECTED]
wrote:
Hello Folks!
I've got a little problem here, which which really creeps me out at the
moment.
I've got some strings, which only contain numbers plus eventually one
character as si-postfix (k for kilo, m for mega, g for giga). I'm trying
to convert those strings to integers, with this function:
def eliminate_postfix(value):
if type(value) is str:
Don't use is unless you are really sure that == won't do the job.
Better idiom:
if isinstance(value, str):
value.upper()
This causes your mult is always 1 problem. You need:
value = value.upper()
Why? Because strings are immutable. String methods like upper return a
new string, they don't change the existing string.
if value.endswith('K'):
mult = 1000
elif value.endswith('M'):
mult = 100
elif value.endswith('G'):
mult = 10
else:
mult = 1
if mult is 1:
Lose is. In fact, lose the whole if statement. See below.
value = string.atoi(value)
Don't use deprecated functions from the string module. Use the built-
in float function to convert from text.
else:
value = string.atoi(value[:-1]) * mult
return value
Those last few statements look somewhat tortuous. Try this:
else: # mult would be 1, but we don't need it
return float(value)
return float(value[:-1]) * mult
HTH,
John
--
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Re: String/Number Conversion
On Sep 7, 7:29 am, Wojtek Walczak [EMAIL PROTECTED] wrote: On Sat, 06 Sep 2008 23:04:14 +0200, Andreas Hofmann wrote: if mult is 1: ^^ You're testing for identity, not for equality. Change it to if mult == 1. Is it alright now? Although he definitely should not be using is here, that can not be the problem if he is using CPython. As an optimisation, small integers are interned i.e. for each small integer, there is only one object. a = 1 b = 1 a is 1 True b is 1 False id(a) 10897704 id(1) 10897704 id(b) 11893004 id(1) 12633044 -- http://mail.python.org/mailman/listinfo/python-list
Re: String/Number Conversion
Andreas Hofmann, there are several problems in your code:
if type(value) is str:
Better to use isinstance() and to compare it with basestring instead.
value.upper()
This does nothing, python strings are immutable, so they don't get
changed in-place, so you have to assign that result to some name,
possibly a different name.
I also suggest you to strip the uppered string, to remove head/tail
spaces.
Your indenting isn't much good, I suggest you to use only four spaces
for each indent (you can also use one tab, but I don't suggest this).
if value.endswith('K'):
mult = 1000
elif value.endswith('M'):
mult = 100
elif value.endswith('G'):
mult = 10
else:
mult = 1
This is okay. You can also put those key-values in a dict, that you
can access with the get method with a default 1, but it may be
overkill.
if mult is 1:
value = string.atoi(value)
else:
value = string.atoi(value[:-1]) * mult
return value
Instead of using string.atoi, use the int() builtin.
If you follow my suggestions you will have a function that works in
many situations. It will raise exceptions in other situations, but
that's good.
But to not need much of our help in your future code I suggest you to
use the Python shell and test every line you write. I also suggest you
to start right now using tests, for example like this:
def eliminate_postfix(value):
el_post = eliminate_postfix
el_post(1)
1
el_post(100)
100
el_post()
Traceback (most recent call last):
...
ValueError: invalid literal for int() with base 10: ''
el_post(100g)
1000L
el_post(100G )
1000L
el_post(100 G )
1000L
el_post(100hg)
Traceback (most recent call last):
...
ValueError: invalid literal for int() with base 10: '100H'
el_post( 100 k )
10
el_post( 100m)
1
el_post(u100m)
1
... function code ...
if __name__ == __main__:
import doctest
doctest.testmod()
print Doctests done.\n
That will improve your coding a LOT, reducing your bug count, etc.
Bye,
bearophile
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modules path
Hi there, I moved a few modules into the modules folder (on OSX: /opt/local/lib/ python2.5/site-packages/). They don't show up though when I start IDLE... Is there a way to reload the modules folders in sys.path without logging out and back in? something like source .cshrc in a shell... thanks in advance, Arno -- http://mail.python.org/mailman/listinfo/python-list
Re: String/Number Conversion
Thanks a lot, I got it working now.
Thanks also to the other guys, your numerous hints were really valuable!
Kind regards,
Andy
John Machin schrieb:
On Sep 7, 7:04 am, Andreas Hofmann [EMAIL PROTECTED]
wrote:
Hello Folks!
I've got a little problem here, which which really creeps me out at the
moment.
I've got some strings, which only contain numbers plus eventually one
character as si-postfix (k for kilo, m for mega, g for giga). I'm trying
to convert those strings to integers, with this function:
def eliminate_postfix(value):
if type(value) is str:
Don't use is unless you are really sure that == won't do the job.
Better idiom:
if isinstance(value, str):
value.upper()
This causes your mult is always 1 problem. You need:
value = value.upper()
Why? Because strings are immutable. String methods like upper return a
new string, they don't change the existing string.
if value.endswith('K'):
mult = 1000
elif value.endswith('M'):
mult = 100
elif value.endswith('G'):
mult = 10
else:
mult = 1
if mult is 1:
Lose is. In fact, lose the whole if statement. See below.
value = string.atoi(value)
Don't use deprecated functions from the string module. Use the built-
in float function to convert from text.
else:
value = string.atoi(value[:-1]) * mult
return value
Those last few statements look somewhat tortuous. Try this:
else: # mult would be 1, but we don't need it
return float(value)
return float(value[:-1]) * mult
HTH,
John
--
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RE: Xpath for HTML processing
Hi Astley I can probably help here. Can you tell me exactly what you're trying to accomplish. the xpath query that you listed can be processed using libxml2dom (and a fewo other libs) are you looking to parse a web page, an xml doc, etc... let me know, and we'll see if we can help -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] Behalf Of Astley Le Jasper Sent: Thursday, September 04, 2008 6:17 AM To: python-list@python.org Subject: Xpath for HTML processing Can anyone suggest something inthat can process an XPath like the following: /html/body/table[2]/tbody/tr/td[5]/table/tbody/tr[3]/td/table[3]/ tbody/tr[5]/td Cheers -- http://mail.python.org/mailman/listinfo/python-list -- http://mail.python.org/mailman/listinfo/python-list
Directory creation
Can someone tell me is there any module available to create directories?? I tried os, tempfile. I was facing some issues with os.mkdir(). The mode setting was not proper with this method. I created the directory 'stdin' with '0700' mode using os.mkdir() method. $ ls -alR stdin/ stdin/: total 12 drwx--S--- 2 munisams munisams 4096 Sep 3 02:00 . What is that 'S' in the group permission field?? Thanks, Srini Unlimited freedom, unlimited storage. Get it now, on http://help.yahoo.com/l/in/yahoo/mail/yahoomail/tools/tools-08.html/ -- http://mail.python.org/mailman/listinfo/python-list
found a bug with smtpd, where can i report this?
Hi, Where should i report the bug? smtpd bug. Marcus.CM -- http://mail.python.org/mailman/listinfo/python-list
Learning Python
Hi im currently starting to learn python in sixth form at school any tips? GET FREE 5GB EMAIL - Check out spam free email with many cool features! Visit http://www.inbox.com/email to find out more! -- http://mail.python.org/mailman/listinfo/python-list
Re: max(), sum(), next()
David C. Ullrich dullr...rynet.com wrote: Think about all the previously elected female or black presidents of the US. Which one was the tallest? The current King of France? - Hendrik -- http://mail.python.org/mailman/listinfo/python-list
Re: atomic section in code
Fredrik Lundh fredr...ware.com wrote: sounds like he wants/needs non-cooperative, mandatory locking. Could one get there using ctypes to disable interrupts? Cross Platform? I can think of lots of hassles, starting with permissions to use the privileged instructions. - Hendrik -- http://mail.python.org/mailman/listinfo/python-list
Use BeautifulSoup to delete certain tag while keeping its content
Dear all, I have the following html code: td valign=top headers=col1 font size=2 Center Bank br / Los Angeles, CA /font /td td valign=top headers=col1 font size=2 Salisbury Bank and Trust Company font face=arial, helvetica size=2 color=#000 br / Lakeville, CT /font /font /td How should I delete the 'font' tags while keeping the content inside? Ideally I want to get: td valign=top headers=col1 Center Bank br / Los Angeles, CA /td td valign=top headers=col1 Salisbury Bank and Trust Company br / Lakeville, CT /td Thank you. Jackie -- http://mail.python.org/mailman/listinfo/python-list
Multicore-programming?
If I buy a multicore computer and I have really intensive program. How would that be distributed across the cores? Will algorithms always have to be programmed and told specifically to run on several cores so if not told it will only utilize one core? So is the free lunch really over or is this just an overhyped phenomena? Is threading with Python hard? Can you start several processes with Python or just threads? -- http://mail.python.org/mailman/listinfo/python-list
Cathing several potential errors?
if i do try: something except TypeError, IndexError: pass only the first error will get caught. I dont want to use Exception and catch all errors, but just 2. how can i do that? -- http://mail.python.org/mailman/listinfo/python-list
Re: modules path
On Sep 7, 8:03 am, Python [EMAIL PROTECTED] wrote: Hi there, I moved a few modules into the modules folder (on OSX: /opt/local/lib/ python2.5/site-packages/). They don't show up though when I start IDLE... Is there a way to reload the modules folders in sys.path without logging out and back in? I know nothing about OS X, but no reload step should be necessary. Each Python process, whether run from IDLE or some other tool or from the shell, will form its own idea of sys.path. So: What modules? What type of file (.py, .pyc, .egg, .zip, .so) are you talking about? Did their documentation say that moving the files into site-packages was all the installation that was needed? What does don't show up when I start IDLE mean? When you start IDLE and do import sys, pprint pprint.pprint(sys.path) do you see the site-packages directory containing the module files? What happens when you do import amodule # substitute correct module name here ? Repeat the above two steps for each of (1) running Python from the shell (2) running Python from the shell with the -v option HTH, John -- http://mail.python.org/mailman/listinfo/python-list
Re: String/Number Conversion
Andreas Hofmann wrote: I've got some strings, which only contain numbers plus eventually one character as si-postfix (k for kilo, m for mega, g for giga). I'm trying to convert those strings to integers, with this function: Why bother to always switch the case if you only use a few values? Also, the Python style is to do an operation and handle failures, rather than test first. Try something like: _units = dict(K=1000, M=100, G=10, k=1000, m=100, g=10) def eliminate_postfix(value): try: return _units[value[-1]] * int(value[: -1]) except (TypeError, KeyError): return int(value) If you normally do not have the suffixes, then switch it around: def eliminate_postfix(value): try: return int(value) except ValueError: return _units[value[-1]] * int(value[: -1]) If this is really SI units, you likely are doing real measurements, so I'd consider using float instead of int in the above. --Scott David Daniels [EMAIL PROTECTED] -- http://mail.python.org/mailman/listinfo/python-list
Re: Cathing several potential errors?
On Sat, 6 Sep 2008 15:13:45 -0700 (PDT), cnb wrote: if i do try: something except TypeError, IndexError: pass Parenthesize them: except (TypeError, IndexError): -- Regards, Wojtek Walczak, http://tosh.pl/gminick/ -- http://mail.python.org/mailman/listinfo/python-list
Re: Cathing several potential errors?
On Sep 7, 8:13 am, cnb [EMAIL PROTECTED] wrote: if i do try: something except TypeError, IndexError: pass only the first error will get caught. I dont want to use Exception and catch all errors, but just 2. how can i do that? The syntax for what you can have between except and : is: [expression [, target]] 'target' is an optional name to be bound to the actual exception object that is raised. If you want to catch multiple kinds of exception, 'expression' needs to be a tuple. See http://docs.python.org/tut/node10.html#SECTION001030 and http://docs.python.org/ref/try.html Cheers, John -- http://mail.python.org/mailman/listinfo/python-list
Re: Learning Python
On Sep 6, 3:17 pm, James Pilling [EMAIL PROTECTED] wrote: Hi im currently starting to learn python in sixth form at school any tips? Just pickup a good book and make sure you code all the examples and exercises yourself, even if it seems easy. Have fun with Python! regards, Subeen. http://love-python.blogspot.com -- http://mail.python.org/mailman/listinfo/python-list
Re: Multicore-programming?
cnb wrote: If I buy a multicore computer and I have really intensive program. How would that be distributed across the cores? Will algorithms always have to be programmed and told specifically to run on several cores so if not told it will only utilize one core? I believe that has always been true. So is the free lunch really over or is this just an overhyped phenomena? Is threading with Python hard? Opinions vary, mostly depending on experience. But Python threads do not distribute across processors. Can you start several processes with Python or just threads? import subprocess and read the manual for that module -- http://mail.python.org/mailman/listinfo/python-list
Re: Cathing several potential errors?
cnb wrote: if i do try: something except TypeError, IndexError: pass only the first error will get caught. I dont want to use Exception and catch all errors, but just 2. how can i do that? -- http://mail.python.org/mailman/listinfo/python-list what you're doing is assigning the value of TypeError to the name IndexError try: somthing except (TypeError, IndexError): pass use except (TypeError, IndexError), e: print e if you want to print the error -- http://mail.python.org/mailman/listinfo/python-list
Re: Multicore-programming?
On 7 Sep, 00:06, cnb [EMAIL PROTECTED] wrote: If I buy a multicore computer and I have really intensive program. How would that be distributed across the cores? It typically depends on how the work done by the program is performed. Will algorithms always have to be programmed and told specifically to run on several cores so if not told it will only utilize one core? Some algorithms lend themselves to parallelisation; others do not. Sometimes tools and runtimes can help by executing some instructions in parallel. So is the free lunch really over or is this just an overhyped phenomena? The free lunch ended a few minutes ago. ;-) Is threading with Python hard? Can you start several processes with Python or just threads? You can start both processes and threads with Python, although the effect of starting many threads - the actual concurrency - will depend on which implementation of Python you're using and where the bulk of the work is performed. If you're spending a lot of CPU time in processing data, and if that processing is taking place in Python code, then for the most effective threading you should consider an implementation like Jython or IronPython which supports free-threading. If most of the work happens in extension code (where you'd probably have little choice about using CPython, anyway), then it might be the case that the extension releases the global interpreter lock in CPython and you might then be able to benefit from having many threads doing work simultaneously, although I imagine that the extension would itself need to be thread- safe, too. If you're spending a lot of time moving data around, performing communication, and so on, then multiple threads may still be effective in CPython, since some of them might be getting a system call to read or write data, thus freeing the CPU for the others. These kinds of situations lend themselves to other approaches such as asynchronous processing of data, however. It doesn't sound like this is like your program, if by intensive you mean high levels of CPU activity. As you note, the alternative to threads is processes, and many people advocate multi-process, shared nothing solutions. Here's a list which covers multicore and SMP-related solutions as well as high-end clustering solutions: http://wiki.python.org/moin/ParallelProcessing Although the processing module is part of Python 2.6/3.0 as the multiprocessing module, you might want to at least look at the pp, pprocess and papyros solutions. My aim with pprocess was to target multicore UNIX-like systems with an unintrusive API; pp and papyros, on the other hand, seek to cover larger scale systems as well, and I think that the way papyros has been done has some merit, mostly because if you wanted to combine convenience with distributed processing, you'd want to choose distributed object technologies as the foundation (CORBA would have been good for this, too, at least for multi-language support, but its APIs can also seem quite intimidating). Paul -- http://mail.python.org/mailman/listinfo/python-list
Re: Multicore-programming?
On Sep 7, 8:06 am, cnb [EMAIL PROTECTED] wrote: If I buy a multicore computer and I have really intensive program. How would that be distributed across the cores? AFAIK, a single process wouldn't be distributed automatically. Will algorithms always have to be programmed and told specifically to run on several cores so if not told it will only utilize one core? AFAIK, yes. See (for example) http://www.parallelpython.com/ So is the free lunch really over There is no such thing as a free lunch. Something which has never existed can't be over. or is this just an overhyped phenomena? These days, every IT phenomenon is over-hyped. If you have a CPU-intensive Python program, you may want to consider: (1) checking that there are not faster/better algorithms for doing what you want in Python, either built-in or in a 3rd-party library (2) using psyco (3) checking your code for sub-optimal constructs HTH, John -- http://mail.python.org/mailman/listinfo/python-list
RE: Use BeautifulSoup to delete certain tag while keeping its content
hi jackie, if you don't mind... can i ask what you're looking to accomplish? are you looking to simply get the text/string data, or something else??? -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] Behalf Of Jackie Wang Sent: Saturday, September 06, 2008 8:12 AM To: python-list@python.org Subject: Use BeautifulSoup to delete certain tag while keeping its content Dear all, I have the following html code: td valign=top headers=col1 font size=2 Center Bank br / Los Angeles, CA /font /td td valign=top headers=col1 font size=2 Salisbury Bank and Trust Company font face=arial, helvetica size=2 color=#000 br / Lakeville, CT /font /font /td How should I delete the 'font' tags while keeping the content inside? Ideally I want to get: td valign=top headers=col1 Center Bank br / Los Angeles, CA /td td valign=top headers=col1 Salisbury Bank and Trust Company br / Lakeville, CT /td Thank you. Jackie -- http://mail.python.org/mailman/listinfo/python-list -- http://mail.python.org/mailman/listinfo/python-list
Re: Numeric literal syntax
[EMAIL PROTECTED] writes: For Python 2.7/3.1 I'd now like to write a PEP regarding the underscores into the number literals, like: 0b_0101_, 268_435_456 etc. +1 on such a capability. -1 on underscore as the separator. On 9/1/2008 9:13 PM Ben Finney apparently wrote: When you proposed this last year, the counter-proposal was made URL:http://groups.google.com/group/comp.lang.python/msg/18123d100bba63b8?dmode=source to instead use white space for the separator, exactly as one can now do with string literals. Yuck. Repeating a mistake means two mistakes. But I would hate less the use of nobreak spaces, since any decent editor can reveal them. Alan Isaac -- http://mail.python.org/mailman/listinfo/python-list
Re: modules path
On 7 sep 2008, at 00:25, John Machin wrote: On Sep 7, 8:03 am, Python [EMAIL PROTECTED] wrote: Hi there, I moved a few modules into the modules folder (on OSX: /opt/local/ lib/ python2.5/site-packages/). They don't show up though when I start IDLE... Is there a way to reload the modules folders in sys.path without logging out and back in? I know nothing about OS X, but no reload step should be necessary. Each Python process, whether run from IDLE or some other tool or from the shell, will form its own idea of sys.path. So: What modules? What type of file (.py, .pyc, .egg, .zip, .so) are you talking about? Did their documentation say that moving the files into site-packages was all the installation that was needed? What does don't show up when I start IDLE mean? When you start IDLE and do import sys, pprint pprint.pprint(sys.path) do you see the site-packages directory containing the module files? What happens when you do import amodule # substitute correct module name here ? Repeat the above two steps for each of (1) running Python from the shell (2) running Python from the shell with the -v option HTH, John -- I installed pyGTK from MacPorts for some reason Macports installs these modules in the /opt/ folder even in an old python folder: python 2.4, while my current version is 2.5 both are not in sys.path... i appended the path and IDLE found them I should have thought a bit more before asking... saturday night... why am I here anyway ;) now one question came up, how do I make those path permanent? i mean, sys.path.append(path) adds it for the current session, yet when i logout of IDLE and start it again it's gone... how do i keep it in there? thanks for the answer John... Arno -- http://mail.python.org/mailman/listinfo/python-list
Re: Learning Python
James Pilling wrote: Hi im currently starting to learn python in sixth form at school any tips? GET FREE 5GB EMAIL - Check out spam free email with many cool features! Visit http://www.inbox.com/email to find out more! There are suggestions here: http://wiki.python.org/moin/PythonBooks Good luck, Colin W. -- http://mail.python.org/mailman/listinfo/python-list
Re: Seeking ideas for a cron implementation
On Aug 22, 1:51 pm, Sean DiZazzo [EMAIL PROTECTED] wrote: On Aug 22, 1:30 pm, Karthik Gurusamy [EMAIL PROTECTED] wrote: Hi, I'm working on acronlike functionality for my application. The outer loops runs continuously waking every x seconds (say x=180, 300, ..). It needs to know what events incronhas expired and for each event do the work needed. It's basically like unixcronor like a calendar application with some restrictions. The outer loop may come back a lot later and many events might have missed their schedule -- but this is okay.. We don't have to worry about missed events (if there were n misses, we just need to execute call back once). Let's take some examples [Let e denotes an event] e1: hour=1 min=30 # Run every day once at 1:30 AM e2: wday=0, hour=1 min=0 # run every Monday at 1 AM e3: month=10, day=10, hour=10 min=0 # run on October 10th, 10 AM every year class Cron_Event (object): def __init__ (year=None, month=None, day=None, hour=None ..etc) # do init classCron(object): def __init__ (): # do init def event_add (e): # add an event def execute() # see if any events has expired .. call it's callback # I'm looking for ideas on how to manage the events here From outer loop cron=Cron() # create various events like e1 = Cron_Event(hour=1) cron.event_add(e1) e2 = Cron_Event(wday=0, hour=1) cron.event_add(e2) while True: sleep x seconds (or wait until woken up) cron.execute() # do other work.. x may change here If I can restrict to hour and minute, it seems manageable as the interval between two occurrences is a constant. But allowing days like every Monday or 1st of every month makes things complicated. Moreover I would like each constraint in e to take on multiple possibilities (like every day at 1AM, 2 AM and 4 AM do this). I'm looking for solutions that can leverage datetime.datetime routines. My current ideas include for each e, track the next time it will fire (in seconds since epoch as given by time.time()). Once current time has passed that time, we execute the event. e.g. datetime.datetime.now() datetime.datetime(2008, 8, 22, 13, 19, 54, 5567) time.time() 1219436401.741966 --- compute event's next firing in a format like this The problem seems to be how to compute that future point in time (in seconds since epoch) for a generic Cron_Event. Say how do I know the exact time in future that will satisfy a constraint like: month=11, wday=1, hour=3, min=30 # At 3:30 AM on a Tuesday in November Thanks for your thoughts. Karthik I only scanned your message, but maybe datetime.timedelta() will help.. import datetime now = datetime.datetime.now() print now 2008-08-22 13:48:49.335225 day = datetime.timedelta(1) print day 1 day, 0:00:00 print now + day 2008-08-23 13:48:49.335225 Thanks, I found using a more efficient algorithm tricky and seemed error prone. [I do welcome ideas still if anyone has a cool solution] I used your idea and took the easy way out by using a brute-force search. Here is an outline if anyone faces similar problem: hours, minutes are lists: say for every day at 1:30 pm and 2:45 pm, hours=[13, 14] and minutes=[30, 45,]. I restricted myself to minutes and hours (and every day) to simplify the problem. def set_expiry_time_check_in_a_day (self, now, target, hours, mins, flags=set()): A small utility routine to simulate 'goto' Looks like now could be computed inside this function -- the small drift due to time taken in this function should be negligible # let's see if in today we can find an expiry # we do brute force search starting with the smallest hour for hour in hours: for min in mins: target = target.replace(hour=hour, minute=min, second=0, microsecond=0) if 'is_debug_1' in flags: print Trying target time: %s... % target if target now: if 'is_debug_1' in flags: print Found target time: %s % (target, ) return target # simulates a break from two loops return None def set_expiry_time (self, event, flags=set()): For a given event, compute and remember when it will fire next now = datetime.datetime.now() target = now # start checking from now.. # assumption, hours and mins are atleast one int element array # and they are in sorted order hours = event.spec['hours'] mins = event.spec['minutes'] tries = 0 while True: # runs of each day.. tomorrow ... tries += 1 if tries 50: #
Re: Use BeautifulSoup to delete certain tag while keeping its content
On 6 Sep, 17:11, Jackie Wang [EMAIL PROTECTED] wrote: I have the following html code: td valign=top headers=col1 font size=2 Center Bank br / Los Angeles, CA /font /td td valign=top headers=col1 font size=2 Salisbury Bank and Trust Company font face=arial, helvetica size=2 color=#000 br / Lakeville, CT /font /font /td How should I delete the 'font' tags while keeping the content inside? This sounds like an editing exercise, really. If you're comfortable learning a new tool, I can recommend XSLT for this kind of job. Here's the stylesheet: ?xml version=1.0? xsl:stylesheet version=1.0 xmlns:xsl=http://www.w3.org/1999/XSL/ Transform xsl:template match=font xsl:apply-templates/ /xsl:template xsl:template match=@*|node() xsl:copy xsl:apply-templates select=@*|node()/ /xsl:copy /xsl:template /xsl:stylesheet This just describes two things: firstly, that you want to recognise font elements and to include their contents, not each element's start and end tags; secondly, that all other parts of the document should be copied. You can apply stylesheets using a number of XSL processors. The xsltproc program is usually available where libxslt is installed, and although I'm sure others will be along to tell you all about their favourite libraries and tools, here's how I use mine within Python: # XSLTools: http://www.python.org/pypi/XSLTools # libxml2dom: http://www.python.org/pypi/libxml2dom import XSLTools.XSLOutput import libxml2dom # If s is the document text... d = libxml2dom.parseString(s) # Save the above stylesheet to a file somewhere, then... proc = XSLTools.XSLOutput.Processor([/tmp/no-font.xsl]) # Get the result document d2 = proc.get_result(d) Anyway, this is just one option of many to deal with this kind of problem. Paul -- http://mail.python.org/mailman/listinfo/python-list
Setter Propertys' mro?
Whats the mro (method resolution order) of a setter property (__set__
on a descriptor).
i seem to be experiencing some weird issue with them.
for example
class test:
... def _test(self):
... return 4
... def _stest(self):pass # dont change value
... def _dtest(self,value):pass
... p=property(_test,_stest,_dtest)
t=test()
t.p
4
t.p=5
t.p
5
Why is that being 'overridden' ( by that i mean that it is storing
that value in t's __dict__)
t.__dict__
{'t': 5}
why DIDNT the setter get hit?
however, if i specify the metaclass in the class definition it works
just fine...
class test:
__metaclass__=type
def _test(self):
return 4
def _stest(self,value):pass # dont change value
def _dtest(self):pass
p=property(_test,_stest,_dtest)
t=test()
t.p
4
t.p=5
t.p
4
why do i have to set the __metaclass__ ? this seems like a bug?
i know that i probably shouldn't worry about this because if a
programmer does want to set my value and it causes an error, thats his
problem but this bothers me. whats the point of the __set__ method
then?
Thanks in advanced.
--
Cipher
--
http://mail.python.org/mailman/listinfo/python-list
Re: found a bug with smtpd, where can i report this?
On Sep 5, 4:01 am, Marcus.CM [EMAIL PROTECTED] wrote: Hi, Where should i report the bug? smtpd bug. Marcus.CM http://bugs.python.org/ -- http://mail.python.org/mailman/listinfo/python-list
Re: Learning Python
James, I have several Python books and am currently working my way through John Zelle's PYTHON PROGRAMMING: An Introduction to Computer Science (Publisher: Franklin, Beedle Associates, ISBN-10: 1887902996, ISBN-13: 978-1887902991). I think this is a very good introduction to both Python AND programming I would highly recommend it. If you finish the Zelle book then you can go onto Problem Solving With Algorithms And Data Structures Using Python by Bradley N. Miller and David L. Ranum (Publisher: Franklin Beedle Associates, ISBN-10: 1590280539, ISBN-13: 978-1590280539). These are equivalent to Python 101 and 201. Regards, Peter -- *Peter Anderson* There is nothing more difficult to take in hand, more perilous to conduct, or more uncertain in its success, than to take the lead in the introduction of a new order of things—Niccolo Machiavelli, /The Prince/, ch. 6 -- http://mail.python.org/mailman/listinfo/python-list
Re: Setter Propertys' mro?
On Sep 6, 2008, at 9:15 PM, cipher wrote: Whats the mro (method resolution order) of a setter property (__set__ on a descriptor). i seem to be experiencing some weird issue with them. for example class test: You have to use class test(object). Only new style classes accepts properties. Cheers Tommy -- http://mail.python.org/mailman/listinfo/python-list
Re: atomic section in code
Hendrik van Rooyen [EMAIL PROTECTED] wrote: Fredrik Lundh fredr...ware.com wrote: sounds like he wants/needs non-cooperative, mandatory locking. More accurately, he THINKS he wants/needs mandatory locking. We need to find out what he's really trying to accomplish before we can suggest something that is actually achievable. Could one get there using ctypes to disable interrupts? No. That can't be done in user mode in any operating system where Python runs. Even in kernel mode, it's not reliable, because disabling interrupts only affects one core. -- Tim Roberts, [EMAIL PROTECTED] Providenza Boekelheide, Inc. -- http://mail.python.org/mailman/listinfo/python-list
Re: Determining Processor Vender
aha [EMAIL PROTECTED] wrote: Dose anyone know of a cross-platform method for determining the vendor of a processor? Under linux I can check /proc/cpuinfo. What I'd like to be able to do is determine if a processor is AMD or Intel, so that I can use the appropriate numerical libraries for my application. If you have a numerical library that uses processor-specific instructions, then the library must be in C with assembler. If so, just add another function that does a cpuid instruction and return the results. -- Tim Roberts, [EMAIL PROTECTED] Providenza Boekelheide, Inc. -- http://mail.python.org/mailman/listinfo/python-list
Re: Multicore-programming?
cnb [EMAIL PROTECTED] wrote: So is the free lunch really over or is this just an overhyped phenomena? Remember that your computer is not running one single program. An idle computer on either Windows or Linux typically has dozens of processes running. Even if all of those programs are single-threaded, you'll still be able to keep all of the cores busy. -- Tim Roberts, [EMAIL PROTECTED] Providenza Boekelheide, Inc. -- http://mail.python.org/mailman/listinfo/python-list
Re: Numeric literal syntax
On Sat, 06 Sep 2008 23:30:03 +, Alan G Isaac wrote: [EMAIL PROTECTED] writes: For Python 2.7/3.1 I'd now like to write a PEP regarding the underscores into the number literals, like: 0b_0101_, 268_435_456 etc. +1 on such a capability. -1 on underscore as the separator. On 9/1/2008 9:13 PM Ben Finney apparently wrote: When you proposed this last year, the counter-proposal was made URL:http://groups.google.com/group/comp.lang.python/ msg/18123d100bba63b8?dmode=source to instead use white space for the separator, exactly as one can now do with string literals. Yuck. Repeating a mistake means two mistakes. A lot of us don't think that white space between string literals was a mistake. A lot of us consider it a desirable feature. But I would hate less the use of nobreak spaces, since any decent editor can reveal them. How do you type a nobreak space? It's also probably a bad idea for Python the language to depend on developers using a decent editor, since many people disagree on what a decent editor is, and many other people don't have access to whatever you consider a decent editor. -- Steven -- http://mail.python.org/mailman/listinfo/python-list
Re: max(), sum(), next()
On Sat, 06 Sep 2008 11:22:07 -0700, Mensanator wrote: [...] They could have decided that sum must take at least two arguments, because addition requires two arguments and it's meaningless to talk about adding a single number without talking about adding it to something else. But they didn't. Ok. But the problem is they DID in SQL: x + Null = Null. Sheesh. That's not a problem, because Python is not trying to be a dialect of SQL. If you want a NULL object, then there are recipes on the web that will give you one. Then all you need to do is call sum(alist or [NULL]) and it will give you the behaviour you want. [...] Here's a real world example (no ivory tower stuff): An oil refinery client has just excavated a big pile of dirt to lay a new pipeline. [snip details] Can't I just use a sum of 0 to tell me when data is missing? No, because in some cases the reporting limit of undetected compounds is set to 0. You can't use a sum of 0 to indicate when data is missing, full stop. The data may require 15 tests when only 3 have actually been done: sum([1.2e-7, 9.34e-6, 2.06e-8]) Missing data and a non-zero sum. How should sum() deal with that? The answer is that sum() can't deal with that. You can't expect sum() to read your mind, know that there should be 15 items instead of 3, and raise an error. So why do you expect sum() to read your mind and magically know that zero items is an error, especially when for many applications it is NOT an error? The behaviour you want for this specific application is unwanted, unnecessary and even undesirable for many other applications. The solution is for *you* to write application-specific code to do what your application needs, instead of relying on a general purpose function magically knowing what you want. -- Steven -- http://mail.python.org/mailman/listinfo/python-list
Re: Setter Propertys' mro?
On Sat, 06 Sep 2008 18:15:33 -0700, cipher wrote: Whats the mro (method resolution order) of a setter property (__set__ on a descriptor). i seem to be experiencing some weird issue with them. for example class test: Unless you're using Python 3, there's your problem right there. In Python 2.x, properties only work correctly for new style classes, not classic classes. Change the above line to: class Test(object): # by convention, classes start with Uppercase. and all should work (or at least you'll discover new and exciting different problems with your code). however, if i specify the metaclass in the class definition it works just fine... class test: __metaclass__=type which is more or less the same as inheriting from object, except uglier. -- Steven -- http://mail.python.org/mailman/listinfo/python-list
Mail delivery problems
In the last two days I have posted relies twice to the Python List. Each time my e-mail has listed successfully but I have received a reply like the following: This is an automatically generated Delivery Status Notification. Delivery to the following recipients failed. [EMAIL PROTECTED] Reporting-MTA: dns;delhi-prod01.india.kring.com Received-From-MTA: dns;kring-vt01 Arrival-Date: Sun, 7 Sep 2008 07:16:17 +0530 Final-Recipient: rfc822;[EMAIL PROTECTED] Action: failed Status: 5.2.2 X-Display-Name: Ajay Deshpande Subject: Re: Learning Python From: Peter Anderson [EMAIL PROTECTED] Date: Sun, 07 Sep 2008 11:41:03 +1000 To: python-list@python.org The text of my message... Is this a problem? Peter -- *Peter Anderson* There is nothing more difficult to take in hand, more perilous to conduct, or more uncertain in its success, than to take the lead in the introduction of a new order of things—Niccolo Machiavelli, /The Prince/, ch. 6 -- http://mail.python.org/mailman/listinfo/python-list
Re: Multicore-programming?
On 7 Sep, 00:06, cnb [EMAIL PROTECTED] wrote: If I buy a multicore computer and I have really intensive program. How would that be distributed across the cores? Distribution of processes and threads across processors (cores or CPUs) is managed by the operating system. Will algorithms always have to be programmed and told specifically to run on several cores so if not told it will only utilize one core? One particular program has to be programmed for concurrency to utilize multiple cores. But you typically have more than one program running. So is the free lunch really over or is this just an overhyped phenomena? Two slow cores are better than one fast for most purposes. For one thing, it saves power. It's good for the battries and environment alike. Is threading with Python hard? It's not harder than with other systems. You just subclass threading.Thread, which has almost the same interface as Java threads. Threading with Python is perhaps a bit easier than with other common platforms, due to the Queue.Queue object and the lack of volatile objects. Can you start several processes with Python or just threads? You can do both. However, remember that Python threads only do what threads were designed to do back in the 1990s. That is asynchrony for I/O and UIs, not concurrency on multiple processors for CPU bound computing. This is due to the Global Interpreter Lock. The GIL is better than fine-grained locks for single-threading and concurrency with multiple processes, but prevent python threads form being used for concurrency (just as well). You can do concurrency with Java threads or Win32 threads, but this is merely a side-effect. You will often see claims form novice programmers that threads are the only route to concurrency on multi- core CPUs. In addition to the existence of processes, direct use of threads from Java, .NET, POSIX, or Win32 APIs is not even the preferred way of programming for concurrency. Tinkering with low-level threading APIs for concurrency is error-prone and inefficient. You will spend a lot of time cleansing your code of dead-locks, live- locks, volatile objects not being declared volatile, and race conditions. In addition to that, chances are your code will not perform or scale very well due to memory contention, cache line misses, inefficient use of registers due to volatile objects, etc. The list is endless. That is why Java 6 and .NET 3.5 provide other abstractions for multi-core concurrency, such as ForkJoin and Parallel.For. This is also the rationale for using an OpenMP enabled compiler for C or Fortran, auto-vectorizing C or Fortran compilers, and novel languages like cilk and erlang. Traditionally, concurrency om parallel computers have been solved using tools like BSPlib, MPI, vectorizing Fortran compilers, and even ebarassingly parallel (running multiple instances of the same program on different data). OpenMP is a recent addition to the concurrency toolset for SMP type parallel computers (to which multi- core x86 processors belong). If you really need concurrency with Python, look into MPI (PyMPI, PyPAR, mpi4py), Python/BSP, subprocess module, os.fork (excluding Windows), pyprocessing package, or Parallel Python. BSP is probably the least error-prone paradigm for multi-core concurrency, albeit not the most efficient. If you decide to move an identified bottleneck from Python to C or Fortran, you also have the option of using OpenMP or cilk to ease the work of programming for concurrency. This is my preferred way of dealing with bad bottlenecks in numerical computing. Remember that you need not learn the overly complex Python C API. Cython, ctypes, f2py, or scipy.weave will do just as well. This approach will require you to manually release the GIL, which can be done in several ways: - In C extensions between Py_BEGIN_ALLOW_THREADS and Py_END_ALLOW_THREADS macros. - When calling DLL methods using ctypes.cdll or ctypes.windll (not ctypes.pydll). - In a with nogil: block in a Cython/Pyrex extension. - With f2py or SWIG, although I have not looked at the details. (I don't use them.) Other things to consider: - Programs that run fast enough run fast enough, even if they only utilize one core. To qoute C.A.R. Hoare and Donald Knuth, premature optimization is the root of all evil in computer programming. - Psyco, a Python JIT compiler, will often speed up algorithmic code. Using psyco require to change to your code. Try it and see if your programs runs fast enough afterwards. YouTube is rumoured to use psyco to speed ut their Python backend. - Always use NumPy or SciPy if you do numerical work. They make numerical code easier to program. The numerical code also runs a lot faster than a pure python equivalent. - Sometimes Python is faster than your hand-written C. This is particularly the case for Python code that make heavy use of built-in primitives and objects from the standard library. You will spend a lot of time tuning a linked list or
Re: Multicore-programming?
On 7 Sep, 06:24, sturlamolden [EMAIL PROTECTED] wrote: - Psyco, a Python JIT compiler, will often speed up algorithmic code. Using psyco require to change to your code. Typo. It should say Using psyco does not require you to change your code. -- http://mail.python.org/mailman/listinfo/python-list
Re: Setter Propertys' mro?
On Sep 6, 9:10 pm, Steven D'Aprano [EMAIL PROTECTED] cybersource.com.au wrote: On Sat, 06 Sep 2008 18:15:33 -0700, cipher wrote: Whats the mro (method resolution order) of a setter property (__set__ on a descriptor). i seem to be experiencing some weird issue with them. for example class test: Unless you're using Python 3, there's your problem right there. In Python 2.x, properties only work correctly for new style classes, not classic classes. Change the above line to: class Test(object): # by convention, classes start with Uppercase. and all should work (or at least you'll discover new and exciting different problems with your code). however, if i specify the metaclass in the class definition it works just fine... class test: __metaclass__=type which is more or less the same as inheriting from object, except uglier. -- Steven Thanks to both of you!! that solved it. i wonder why the getters would work fine though?? neways, wtf do i care :) again, thank you both. __ Cipher -- http://mail.python.org/mailman/listinfo/python-list
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