itools 0.20.4 released
itools is a Python library, it groups a number of packages into a single meta-package for easier development and deployment: itools.catalog itools.i18n itools.uri itools.csv itools.ical itools.vfs itools.datatypesitools.odf itools.web itools.gettext itools.pdf itools.workflow itools.git itools.rest itools.xliff itools.handlers itools.rss itools.xml itools.html itools.stl itools.http itools.tmx The isetup-doc.py script has been removed, now we use epydoc [1,2] for the automatically generated documentation. The itools.http and itools.web packages have seen important fixes, like better support for cookies and better handling of bad requests. The itools.xml and itools.html packages now correctly raise an exception when a close tag is missing at the end of the file. [1] http://epydoc.sourceforge.net/ [2] http://download.ikaaro.org/doc/itools-reference/ Resources - Download http://download.ikaaro.org/itools/itools-0.20.4.tar.gz http://download.ikaaro.org/itools/itools-0.20.4.win32-py2.5.exe http://download.ikaaro.org/itools/itools-0.20.4.win32-py2.4.exe Home http://www.ikaaro.org/itools Mailing list http://mail.ikaaro.org/mailman/listinfo/itools Bug Tracker http://bugs.ikaaro.org/ -- J. David Ibáñez Itaapy http://www.itaapy.com Tel +33 (0)1 42 23 67 45 9 rue Darwin, 75018 Paris Fax +33 (0)1 53 28 27 88 -- 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, February 12, 2008, 08:00pm
=== Leipzig Python User Group === We will meet on Tuesday, February 12 at 8:00 pm at the training center of Python Academy in Leipzig, Germany ( http://www.python-academy.com/center/find.html ). Maik Derstappen will give a presentation about Plone. 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 encouraged to participate. 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 . Mike == Leipzig Python User Group === Wir treffen uns am Dienstag, 12.02.2008 um 20:00 Uhr im Schulungszentrum der Python Academy in Leipzig ( http://www.python-academy.de/Schulungszentrum/anfahrt.html ). Maik Derstappen wird einen Vortrag über Plone halten. 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 Mike -- http://mail.python.org/mailman/listinfo/python-announce-list Support the Python Software Foundation: http://www.python.org/psf/donations.html
ANN: ConfigObj 4.5.1 and validate 0.3.1
After one year and two days since the last release, there is a new release of ConfigObj. * ConfigObj 4.5.1 http://www.voidspace.org.uk/python/configobj.html * Validate 0.3.1 http://www.voidspace.org.uk/python/validate.html This release adds a few new features, plus has several bugfixes and minor performance improvements. Thanks to all those who gave feedback, reported bugs and provided patches. What are ConfigObj and Validate? = **ConfigObj** is a simple to use but powerful configuration file management library. Features include: * Nested sections to any depth * Unicode support * List and multiline values * Integrated with a powerful validation system - including automatic type checking/conversion - repeated sections - and allowing default values * All comments in a file are preserved when writing * The order of keys/sections is preserved * A powerful unrepr mode for storing basic datatypes **validate** is the module (optional) used for config file validation and type marshalling. It can be used outside of ConfigObj for matching string values against a text specification which also does type conversion. Changes in ConfigObj 4.5.1 Distribution updated to include version 0.3.1 of validate. This means that Unicode configspecs now work. ConfigObj will now guarantee that files will be written terminated with a newline. ConfigObj will no longer attempt to import the ``validate`` module, until/unless you call ``ConfigObj.validate`` with ``preserve_errors=True``. This makes it faster to import. New methods ``restore_default`` and ``restore_defaults``. ``restore_default`` resets an entry to its default value (and returns that value). ``restore_defaults`` resets all entries to their default value. It doesn't modify entries without a default value. You must have validated a ConfigObj (which populates the ``default_values`` dictionary) before calling these methods. BUGFIX: Proper quoting of keys, values and list values that contain hashes (when writing). When ``list_values=False``, values containing hashes are triple quoted. Added the ``reload`` method. This reloads a ConfigObj from file. If the filename attribute is not set then a ``ReloadError`` (a new exception inheriting from ``IOError``) is raised. BUGFIX: Files are read in with 'rb' mode, so that native/non-native line endings work! Minor efficiency improvement in ``unrepr`` mode. Added missing docstrings for some overridden dictionary methods. Added the ``reset`` method. This restores a ConfigObj to a freshly created state. Removed old CHANGELOG file. Changes in Validate 0.3.1 == BUGFIX: Unicode checks no longer broken. Improved performance with a parse cache. New ``get_default_value`` method. Given a check it returns the default value (converted to the correct type) or raises a ``KeyError`` if the check doesn't specify a default. Added 'tuple' check and corresponding 'is_tuple' function (which always returns a tuple). BUGFIX: A quoted 'None' as a default value is no longer treated as None, but as the string 'None'. BUGFIX: We weren't unquoting keyword arguments of length two, so an empty string didn't work as a default. BUGFIX: Strings no longer pass the 'is_list' check. Additionally, the list checks always return lists. A couple of documentation bug fixes. Removed CHANGELOG from module. Michael Foord -- http://mail.python.org/mailman/listinfo/python-announce-list Support the Python Software Foundation: http://www.python.org/psf/donations.html
Re: beginner question, function returning object.
Second try (correction) I started with ths: -- def open_pipe(): pipe=PIPE() print pipe return pipe pipe=open_pipe() pipe.parent = self.parent print pipe -- It didn't do what I wanted: when I printed the pipe the second time it was not the same object as the first time. So I changed it to this: def open_pipe(pipe): pipe=PIPE() print pipe pipe = None open_pipe(pipe) pipe.parent = self.parent print pipe It still doesn't do what I wanted: I can't assign the parent property because pipe type is None. I'm not sure enough of what I am doing to tell if I have another error in my code causing the problem. Is either of these examples supposed to work as shown? Is it clear that either example is obviously wrong? -- http://mail.python.org/mailman/listinfo/python-list
Re: Why does list have no 'get' method?
Paul Rubin: I like the suggestion, except it should be port = int(sys.argv.get(1, '8000')) one could imagine your example going wrong in a protocol where 0 is a valid port number. I think a high-level language like Python must have boolean operators (or and not) that behave in a much more clean way, with a simpler semantics. That is they have to return only true or false. Otherwise they are just a source of bugs and confusion. This is a change fit for Python 3. That trick with or/and may look good for Perl, but it's unfit for a language that tries to be clear, readable from people that don't know it much, and good to learn to program. Python has now the if-then expression too that is more clear. Bye, bearophile -- http://mail.python.org/mailman/listinfo/python-list
Re: beginner question, function returning object.
On Thu, 07 Feb 2008 19:14:54 +1100, bambam wrote: I started with ths: -- def open_pipe(): pipe=PIPE() print pipe return pipe pipe=open_pipe() pipe.parent = self.parent print pipe -- It didn't do what I wanted: when I printed the pipe the second time it was not the same object as the first time. Please post actual minimal code that reproduces the problem and a better description of what you get and what you expected instead. What is `PIPE` and where does `self` come from? What are the too ``print``\s printing that makes you think `pipe` isn't bound to the same object? So I changed it to this: def open_pipe(pipe): pipe=PIPE() print pipe pipe = None open_pipe(pipe) pipe.parent = self.parent print pipe It still doesn't do what I wanted: I can't assign the parent property because pipe type is None. Yes because in `open_pipe()` you bind a new object to the local name `pipe` which of course has no effect on the binding of the name `pipe` in the callers namespace. I'm not sure enough of what I am doing to tell if I have another error in my code causing the problem. Is either of these examples supposed to work as shown? Is it clear that either example is obviously wrong? The second is wrong. The first should work if `self` and `PIPE` are bound to appropriate objects. Ciao, Marc 'BlackJack' Rintsch -- http://mail.python.org/mailman/listinfo/python-list
Re: getting all user defined attributes of a class
On Feb 6, 11:07 pm, Amit Gupta [EMAIL PROTECTED] wrote: Hi How do I get user defined attributes of a class? e.g Class A(object) : self.x = 1 -- I want something like: for userattrib in A.getAllUserAttribute() : print userattrib class Meta(type): def __init__(cls, name, bases, attrs): super(Meta, cls).__init__(name, bases, attrs) cls._attrs = attrs.keys() class Base(object): __metaclass__ = Meta def getmembers(self): return [k for k in self.__dict__ if k not in self._attrs] class MyObj(Base): def __init__(self): self.a = 1 self.b = 2 obj = MyObj() print obj.getmembers() ['a', 'b'] setattr(obj, 'c', 3) print obj.getmembers() ['a', 'c', 'b'] HTH Gerard -- http://mail.python.org/mailman/listinfo/python-list
Re: Why does list have no 'get' method?
[EMAIL PROTECTED] wrote: Paul Rubin: I like the suggestion, except it should be port = int(sys.argv.get(1, '8000')) one could imagine your example going wrong in a protocol where 0 is a valid port number. I think a high-level language like Python must have boolean operators (or and not) that behave in a much more clean way, with a simpler semantics. That is they have to return only true or false. Otherwise they are just a source of bugs and confusion. This is a change fit for Python 3. Conditional expressions have clear semantics. Stefan -- http://mail.python.org/mailman/listinfo/python-list
Re: Code block function syntax, anonymous functions decorator
Jean-Paul Calderone schrieb: On Wed, 06 Feb 2008 23:59:27 +0100, Diez B. Roggisch [EMAIL PROTECTED] wrote: [EMAIL PROTECTED] schrieb: def run3( block ): for _ in range( 3 ): block() run3(): normal_suite() Introduces new syntax; arbitrary functions can follow 'colon'. Maintains readability, meaning is consistent. Equivalent to: def run3( block ): for _ in range( 3 ): block() @run3 def anonfunc(): normal_suite() Simplification in cases in which decorators are use often. This is non-sensical - how do you invoke anonfunc? They would all bind to the same name, run3. Or to no name as all, as your spec lacks that. As he said, the decorator version is the _equivalent_ to the syntax he was proposing. The point isn't to decorate the function, so perhaps he shouldn't have used decorator syntax, but instead: def anonfunc(): normal_suite() run3(anonfunc) del anonfunc So it's not non-sensical. It's a request for a piece of syntax. Besides, it's butt-ugly IMHO. But taste comes after proper definition... It's properly defined. Not that I'm endorsing this or anything. I'd rather not see half-assed syntax proposals at all, even if they're super great (and some of the syntax that's made it into Python is much worse than this). Yeah, I missed somehow that the decorator doesn't actually return anything. Diez -- http://mail.python.org/mailman/listinfo/python-list
Re: Is there a way to use .NET DLL from Python
Luis M. González wrote:
On 6 feb, 21:17, Fuzzyman [EMAIL PROTECTED] wrote:
On Feb 6, 9:59 pm, Luis M. Gonz�lez [EMAIL PROTECTED] wrote:
On Feb 6, 6:27 pm, Huayang Xia [EMAIL PROTECTED] wrote:
Hello All,
I have several .NET DLL (I have no source code for them), is there
anyway to use them from python instead of from C#.
Thanks,
Huayang
I used to put my .dll files into the .DLL folder, so I could simply
import them as I would with any other python module.
But since I started using Ironpython 2.0 Alpha* this doesn't work
anymore...
Any hint?
The rule is probably still that the DLLs must be in a directory on
sys.path for the interpreter to find them. Try adding the directory
containing the assemblies to sys.path and see if you can add
references to them.
Michael Foordhttp://www.manning.com/foord
Luis
I tried adding the directory to sys.path.
Still not working...
import sys
sys.path.append('C:\Documents and
Settings\luismg\Escritorio\IronPython-2.0A
8\DLLs')
from ClassLibrary1 import *
Traceback (most recent call last):
File , line unknown, in ##235
File , line unknown, in _stub_##2
ImportError: No module named ClassLibrary1
You need to add references to assemblies before you can import from
the namespaces they contain.
import clr
clr.AddReference('ClassLibrary1')
HTH
Fuzzyman
http://www.manning.com/foord
--
http://mail.python.org/mailman/listinfo/python-list
Re: beginner question, function returning object.
On Thu, 07 Feb 2008 19:14:54 +1100, bambam wrote: Second try (correction) I started with ths: -- def open_pipe(): pipe=PIPE() print pipe return pipe What's PIPE() do? pipe=open_pipe() (Extraneous space removed.) pipe.parent = self.parent What's self? What's it do? What's self.parent and what does it do? print pipe -- It didn't do what I wanted: when I printed the pipe the second time it was not the same object as the first time. How do you know? What makes you think they are different objects? So I changed it to this: def open_pipe(pipe): pipe=PIPE() print pipe pipe = None Again with the extraneous space. open_pipe(pipe) This can't possibly work. What you are doing is this: (1) set the name 'pipe' to None (2) call the function open_pipe() with None as the argument (3) which reassigns the *inner* variable 'pipe' to the result of PIPE(), but doesn't do anything to the *global* variable 'pipe' (4) open_pipe() now returns None, which doesn't get used So as you can see, the global 'pipe' starts off as None, and then nothing happens to it, so it stays None. pipe.parent = self.parent print pipe It still doesn't do what I wanted: I can't assign the parent property because pipe type is None. I'm not sure enough of what I am doing to tell if I have another error in my code causing the problem. Is either of these examples supposed to work as shown? Is it clear that either example is obviously wrong? Your first attempt was almost certainly the correct way to try to do what you want. I suspect that your function PIPE() is broken. -- Steven -- http://mail.python.org/mailman/listinfo/python-list
Re: loading dictionary from a file
Amit Gupta wrote: Need a python trick, if it exists: I have a file that stores key, value in following format -- v1 : k1, v2 : k2 -- Is there a way to directly load this file as dictionary in python. I could do (foreach line in file, split by : and then do dictionary insert). Wondering, if some python built-in function can just read a valid dictionary-file and load it? If you change the format slightly you could use ConfgiObj http://www.voidspace.org.uk/python/configobj.html . key = value key2 = value2 Fuzzyman http://www.voidspace.org.uk/python/weblog/index.shtml Thanks -- http://mail.python.org/mailman/listinfo/python-list
Re: Why does list have no 'get' method?
Denis Bilenko wrote: Why does list have no 'get' method with exactly the same semantics as dict's get, that is return an element if there is one, but do NOT raise an exception if there is not.: def get(self, item, default = None): try: return self[item] except IndexError: return default It is often desirable, for example, when one uses the easiest command-line options parsing - based on absolute positions: Dodging your question slightly (and at the risk of teaching my grandmother to suck eggs) I sometimes use this idiom for checking params. Obviously it only goes so far, but it's fairly compact: Noddy example code import os, sys if __name__ == '__main__': ARGS = None, DEV filename, db = \ (j or i for i, j in map (None, ARGS, sys.argv[1:])) print sys.argv print filename, db /code TJG -- http://mail.python.org/mailman/listinfo/python-list
Re: Adding properties to an instance
[EMAIL PROTECTED] a écrit : On Feb 6, 11:09 pm, [EMAIL PROTECTED] [EMAIL PROTECTED] wrote: While this is technically possible (I tried a couple years ago), it requires hacking the __getattribute__ method, which is something I would not recommand, not only because it can be tricky, but mostly because this is a very critical path wrt/ perfs. (IIRC it also required using custom descriptors, but I'm not really sure about this last point). Performance is pretty important for the class I'm designing so I think __getattribute__ is probably out. The computed properties are only infrequently accessed, but using __getattribute__ slows everything down, right? Indeed - it *is* the attribute lookup mechanism. Better to leave it alone. Before new-style classes, we used the __getattr__/__setattr__ hooks for computed attributes. While this approach is now a bit abandonned in favor of descriptors (properties or custom ones), it still works fine, and is probably the best solution to your problem. Ah, I didn't know about these - it looks as though they might be just the thing since it seems they're only called after all the other methods fail. Right. That looks like there would be no performance hit, I wouldn't need to mess around with dynamically changing the class, and it would automatically deal with the (irritating) feature of having to check if there is already something in the object's dir() with that name. I'll look into this tomorrow - I hope this feature isn't going to be removed in future versions of Python? I really don't think so. It's still has it's use for automatic delegation. And, as is the case here, for per-instance computed attributes. As a side note: the naming symetry between __getattr__ and __setattr__ is a gotcha, since __setattr__ is mostly symetric to __getattribute__ - IOW, customizing __setattr__ is a bit tricky. The naive approach, ie: class Parrot(object): def __setattr__(self, name, val): self.name = val will indeed go into infinite recursion (or would, if the interpreter didn't stop it after a while) The solution is of course to call on the parent class's __setattr__: class Ni(object): def __setattr__(self, name, val): object.__setattr__(self, name, value) HTH -- http://mail.python.org/mailman/listinfo/python-list
Re: Why does list have no 'get' method?
On Thu, 07 Feb 2008 00:20:52 -0800, bearophileHUGS wrote: I think a high-level language like Python must have boolean operators (or and not) that behave in a much more clean way, with a simpler semantics. That is they have to return only true or false. Otherwise they are just a source of bugs and confusion. Well, that's one opinion. Boolean operators can be complicated to understand if you write complicated expressions, or if you don't understand what they do. But otherwise, they're no more complicated than arithmetic expressions. [...] That trick with or/and may look good for Perl, but it's unfit for a language that tries to be clear, readable from people that don't know it much, and good to learn to program. Python has now the if-then expression too that is more clear. Suppose I have two lists, and want to process the first one if it is not empty, otherwise process the second. I'd write it like this: process(mylist or yourlist) You're suggesting I should write it like this: process(mylist if mylist else yourlist) With the greatest respect, I think that if you think the second example is more clear, you're completely bonkers. *grins* -- Steven -- http://mail.python.org/mailman/listinfo/python-list
Re: Why not a Python compiler?
In article [EMAIL PROTECTED], Grant Edwards [EMAIL PROTECTED] wrote: On 2008-02-06, Reedick, Andrew [EMAIL PROTECTED] wrote: One demerit has been marked against your geek card for missing an obvious science pun. Additionally, your membership to the Star Trek Lifestyle Adventure Club has been put on probationary status for the next twelve parsecs. Ouch. Two demerits for using the distance unit parsec in a context where a quantity of time was required. No demerits for Andrew; it is a Star Wars reference, which is quite on topic for this subthread. http://starwars.wikia.com/wiki/Kessel_Run Gary Duzan Motorola HNM -- http://mail.python.org/mailman/listinfo/python-list
Re: Why does list have no 'get' method?
Tim Golden wrote:
Dodging your question slightly (and at the risk of teaching
my grandmother to suck eggs) I sometimes use this idiom for
checking params. Obviously it only goes so far, but it's
fairly compact:
Noddy example code
import os, sys
if __name__ == '__main__':
ARGS = None, DEV
filename, db = \
(j or i for i, j in map (None, ARGS, sys.argv[1:]))
print sys.argv
print filename, db
/code
Thank you for the example. It demonstrates perfectly how
much people miss this feature :)
Raymond Hettinger wrote:
At first blush that example would make it seem like a good idea, but I
don't see how the example could extend past the first index. If the
port argument is optional, how would you know the index position of
optional arguments to follow?
With a dictionary, one could plausibly write:
host = d.get('host', 'http://example.com')
port = d.get('port', 8080)
path = d.get('path', '/')
But would this make sense with a list:
host = s.get(0, 'http://example.com')
port = d.get(1, 8080)
path = d.get(2, '/')
If positions 0 and 1 are optional, how do you expect to know whether
path is going to be at position 2? This problem doesn't exist with
dictionaries because the presence or absence of optional entries does
not affect the key reference to other entries. Accordingly, I
wouldn't expect that dict.get() would have a parallel list.get() with
plausible use cases.
If you want to fill position 2, then positions 0 and 1 are mandatory.
It is the simplest possible option parsing, I didn't said it was the
most flexible :)
But perhaps it was a wrong example altogether.
Consider a couple more snippets, unrelated to command-line options.
(found by searching 'IndexError' in the python standard library)
this snippet from cmd.py:
try:
return self.completion_matches[state]
except IndexError:
return None
transforms into
return self.completion_matches.get(state)
another one from fileinput.py
try:
line = self._buffer[self._bufindex]
except IndexError:
pass
else:
self._bufindex += 1
self._lineno += 1
self._filelineno += 1
return line
line = self.readline()
becomes
line = self._buffer.get(self._bufindex)
if line:
self._bufindex += 1
self._lineno += 1
self._filelineno += 1
return line
line = self.readline()
both examples show reduction by 3 lines.
There's nothing dictionary-specific in 'get', it is
just a special use-case of '__getitem__' that is needed frequently.
Since list has '__getitem__' it deserves to have 'get' too.
--
http://mail.python.org/mailman/listinfo/python-list
Re: Why does list have no 'get' method?
Steven D'Aprano: With the greatest respect, I think that if you think the second example is more clear, you're completely bonkers. *grins* No one is completely normal, I presume :-) I'd like to know what others think about it, about this anti-feature. What I can say is that other computer languages too think that boolean operations must return boolean values only, so I am not alone in my folly :-) Bye, bearophile -- http://mail.python.org/mailman/listinfo/python-list
Re: Why not a Python compiler?
Santiago Romero wrote: I'm impressed with python. I'm very happy with the language and I find Python+Pygame a very powerful and productive way of writing 2D games. I'm not, at this moment, worried about execution speed of the small game I'm working on (it runs at full 60 fps even in an old AMD- K6 450 Laptop computer), but I continue asking me the same question: Why not a Python COMPILER? It would be very nice to be able to output Linux, MAC or Windows binaries of compiled (not bytecompiled) code. It would run faster, it will be smaller in size (I think) Take a look at Cython. It's an optimising Python-to-C compiler for writing Python extensions. So you can basically take a Python module and compile it to C code that runs against the CPython runtime. http://cython.org/ and it will be easy to distribute to people not having python installed. Yes, I know about py2exe, but I'm not sure if that's the right aproach. That's a different focus, but then, there's portable Python. http://www.portablepython.com/ Stefan -- http://mail.python.org/mailman/listinfo/python-list
Re: Suggestions for structure of HTML-generating app
[EMAIL PROTECTED] wrote: On Feb 5, 9:14 pm, Bernard [EMAIL PROTECTED] wrote: On 5 fév, 10:09, [EMAIL PROTECTED] [EMAIL PROTECTED] wrote: Are there any good approaches of doing this kind of thing that I've missed, or am I resigned to having HTML and Python code mixed and so will just have to keep all that nastiness to as few modules as possible? Thanks, Matthew. we use Cheetah templates to do just that at my workplace. we use CherryPy to generate the data and then we pass it on to the Cheetah template which handles the data and add html over it. here's an article on that matter :http://www.onlamp.com/pub/a/python/2005/01/13/cheetah.html Thanks for the pointer to Cheetah. At first glance it looks neat. Cherrytemplate has done well for me so far but I don't think it's under active development any more so it may be time to migrate. You might also be interested in webstring: http://psilib.sourceforge.net/webstring.html (and then, there's tons of other templating packages for Python...) Stefan -- http://mail.python.org/mailman/listinfo/python-list
Re: Suggestions for structure of HTML-generating app
On Feb 5, 9:14 pm, Bernard [EMAIL PROTECTED] wrote: On 5 fév, 10:09, [EMAIL PROTECTED] [EMAIL PROTECTED] wrote: Are there any good approaches of doing this kind of thing that I've missed, or am I resigned to having HTML and Python code mixed and so will just have to keep all that nastiness to as few modules as possible? Thanks, Matthew. we use Cheetah templates to do just that at my workplace. we use CherryPy to generate the data and then we pass it on to the Cheetah template which handles the data and add html over it. here's an article on that matter :http://www.onlamp.com/pub/a/python/2005/01/13/cheetah.html Thanks for the pointer to Cheetah. At first glance it looks neat. Cherrytemplate has done well for me so far but I don't think it's under active development any more so it may be time to migrate. Matthew. -- http://mail.python.org/mailman/listinfo/python-list
Re: smtpd module
Stefan Witzel wrote: Hello, the documentation of the smtpd module in the Python Library Reference is very short, I think. Are there any examples available? Especially I'm interested in the DebuggingServer. Thanks in advance. Stefan Sorry, I found the example - it's in the source file. Stefan -- http://mail.python.org/mailman/listinfo/python-list
Re: Why does list have no 'get' method?
On Feb 7, 8:20 am, [EMAIL PROTECTED] wrote: Paul Rubin: I like the suggestion, except it should be port = int(sys.argv.get(1, '8000')) one could imagine your example going wrong in a protocol where 0 is a valid port number. I think a high-level language like Python must have boolean operators (or and not) that behave in a much more clean way, with a simpler semantics. That is they have to return only true or false. Otherwise they are just a source of bugs and confusion. This is a change fit for Python 3. That trick with or/and may look good for Perl, but it's unfit for a language that tries to be clear, readable from people that don't know it much, and good to learn to program. Python has now the if-then expression too that is more clear. Bye, bearophile Personally, between * foo if foo else bar * foo or bar I prefer the second. Maybe it could be spelt * foo else bar ? Moreover between the following two: * foores = foo() foobar = foores if foores else bar * foobar = foo() or bar I also prefer the second. Maybe it could be spelt * foo() else bar ? I have not thought of parsing issues :) -- Arnaud -- http://mail.python.org/mailman/listinfo/python-list
Re: Why does list have no 'get' method?
Denis Bilenko wrote: Raymond Hettinger wrote: If positions 0 and 1 are optional, how do you expect to know whether path is going to be at position 2? This problem doesn't exist with dictionaries because the presence or absence of optional entries does not affect the key reference to other entries. Accordingly, I wouldn't expect that dict.get() would have a parallel list.get() with plausible use cases. If you want to fill position 2, then positions 0 and 1 are mandatory. It is the simplest possible option parsing, I didn't said it was the most flexible :) d = dict(enumerate(args)) print d[0], d[1], d.get(2) Stefan -- http://mail.python.org/mailman/listinfo/python-list
Re: Traversing python datatypes via http
Mark [EMAIL PROTECTED] wrote Is it possible to traverse say python lists via http:// http is a network protocol. What does that have to do with traversing python lists? Can you clarify what you mean by that? say there is a list in the memory can we traverse the list using list/next list/prev list/first list/last Not with a standard list although its not hard to do by defining your own class wrappibng a list. You can however traverse a list using a standard for loop: for item in [1,2,3,4,5]: print item And you can use range() to generate a set of indices that will allow you to iterate by more unusual step sizes As well as range(), slicing can do; for item in [1,2,3,4,5,6,7,8,9,0][::2]: print item 1 3 5 7 9 for item in [1,2,3,4,5,6,7,8,9,0][::-2]: print item 0 8 6 4 2 Matt. -- This message and any attachments (the message) is intended solely for the addressees and is confidential. If you receive this message in error, please delete it and immediately notify the sender. Any use not in accord with its purpose, any dissemination or disclosure, either whole or partial, is prohibited except formal approval. The internet can not guarantee the integrity of this message. BNP PARIBAS (and its subsidiaries) shall (will) not therefore be liable for the message if modified. Do not print this message unless it is necessary, consider the environment. - Ce message et toutes les pieces jointes (ci-apres le message) sont etablis a l'intention exclusive de ses destinataires et sont confidentiels. Si vous recevez ce message par erreur, merci de le detruire et d'en avertir immediatement l'expediteur. Toute utilisation de ce message non conforme a sa destination, toute diffusion ou toute publication, totale ou partielle, est interdite, sauf autorisation expresse. L'internet ne permettant pas d'assurer l'integrite de ce message, BNP PARIBAS (et ses filiales) decline(nt) toute responsabilite au titre de ce message, dans l'hypothese ou il aurait ete modifie. N'imprimez ce message que si necessaire, pensez a l'environnement. -- http://mail.python.org/mailman/listinfo/python-list
PyGILState_Ensure() produces a deadlock
Hello, In my mixed C++ / Python Application there are situations where a PyGILState_STATE gil_state = PyGILState_Ensure() produces a deadlock. The background is that a call fro python to cpp is directed to another subsystem that tries to access the GIL (through my C++ wrapper) from another thread. Does Pyhon API offer services to ship around that? Other hints? Thanks a lot -- http://mail.python.org/mailman/listinfo/python-list
Re: Adding properties to an instance
As a side note: the naming symetry between __getattr__ and __setattr__ is a gotcha, since __setattr__ is mostly symetric to __getattribute__ - IOW, customizing __setattr__ is a bit tricky. The naive approach, ie: Ah I see - so __setattr__ is called immediately whereas __getattr__ is only called if the other methods fail. Does this mean that __setattr__ incurs the same performance penalty that overriding __getattribute__ would? Possibly I can live with this because I think that most of what I'm doing is getting attributes, or modifying mutable ones, rather than setting them. -- Dan -- http://mail.python.org/mailman/listinfo/python-list
Re: Why not a Python compiler?
On Thu, 07 Feb 2008 11:03:12 +0100, Stefan Behnel [EMAIL PROTECTED] wrote: Santiago Romero wrote: [snip] Why not a Python COMPILER? It would be very nice to be able to output Linux, MAC or Windows binaries of compiled (not bytecompiled) code. It would run faster, it will be smaller in size (I think) Take a look at Cython. It's an optimising Python-to-C compiler for writing Python extensions. So you can basically take a Python module and compile it to C code that runs against the CPython runtime. http://cython.org/ It's a not-quite-Python-to-C compiler. I don't think it is an optimizing compiler either. Can you provide a reference for this? Jean-Paul -- http://mail.python.org/mailman/listinfo/python-list
Re: Looking for library to estimate likeness of two strings
On Wed, 06 Feb 2008 17:32:53 -0600, Robert Kern wrote: Jeff Schwab wrote: ... If the strings happen to be the same length, the Levenshtein distance is equivalent to the Hamming distance. Is this really what the OP was asking for. If I understand it correctly, Levenshtein distance works out the number of edits required to transform the string to the target string. The smaller the more equivalent, but with the OP's problem I would expect table1 table2 brian briam erian I think the OP would like to guess at 'briam' rather than 'erian', but Levenstein would rate them equally good guesses? I know this is pushing it more toward phonetic alaysis of the words or something similar, and thats orders of magnitude more complex. just in case, http://www.linguistlist.org/sp/Software.html#97 might be a good place to start looking into it, along with the NLTK libraries here http://nltk.sourceforge.net/index.php/Documentation Matt. -- This message and any attachments (the message) is intended solely for the addressees and is confidential. If you receive this message in error, please delete it and immediately notify the sender. Any use not in accord with its purpose, any dissemination or disclosure, either whole or partial, is prohibited except formal approval. The internet can not guarantee the integrity of this message. BNP PARIBAS (and its subsidiaries) shall (will) not therefore be liable for the message if modified. Do not print this message unless it is necessary, consider the environment. - Ce message et toutes les pieces jointes (ci-apres le message) sont etablis a l'intention exclusive de ses destinataires et sont confidentiels. Si vous recevez ce message par erreur, merci de le detruire et d'en avertir immediatement l'expediteur. Toute utilisation de ce message non conforme a sa destination, toute diffusion ou toute publication, totale ou partielle, est interdite, sauf autorisation expresse. L'internet ne permettant pas d'assurer l'integrite de ce message, BNP PARIBAS (et ses filiales) decline(nt) toute responsabilite au titre de ce message, dans l'hypothese ou il aurait ete modifie. N'imprimez ce message que si necessaire, pensez a l'environnement. -- http://mail.python.org/mailman/listinfo/python-list
Re: Adding properties to an instance
[EMAIL PROTECTED] a écrit : As a side note: the naming symetry between __getattr__ and __setattr__ is a gotcha, since __setattr__ is mostly symetric to __getattribute__ - IOW, customizing __setattr__ is a bit tricky. The naive approach, ie: Ah I see - so __setattr__ is called immediately whereas __getattr__ is only called if the other methods fail. Yes. Does this mean that __setattr__ incurs the same performance penalty that overriding __getattribute__ would? Not quite AFAICT - there's less going on here. Also, getting an attribute is (usually at least) more common than setting it. Possibly I can live with this because I think that most of what I'm doing is getting attributes, or modifying mutable ones, rather than setting them. Well... Using the __setattr__/__getattr__ hooks is IMHO the simplest solution that can possibly work - far simpler than your previous one at least. As far as I'm concerned, and unless some other point of your specs make this unusable or unpractical, I'd go for this solution first and run a couple benchs on real-life-or-close-to conditions to check if the performance hit is acceptable. -- http://mail.python.org/mailman/listinfo/python-list
Re: Must COMMIT after SELECT (was: Very weird behavior in MySQLdb execute)
On 7 Feb, 08:52, Frank Aune [EMAIL PROTECTED] wrote: On Wednesday 06 February 2008 16:16:45 Paul Boddie wrote: Really, the rule is this: always (where the circumstances described above apply) make sure that you terminate a transaction before attempting to read committed, updated data. How exactly do you terminate a transaction then?Do you terminate a transaction by closing the cursor? No, the transaction is controlled using the connection object in the DB-API, specifically by the commit and rollback methods. Would this indicate that for each query you perform against the db, you should: - Open cursor - Perform query - Close cursor I tend to open a separate cursor for each query whose result set I want to keep around. In other words, if I'm doing a number of queries whose results will not be manipulated via the DB-API (using fetchone, fetchmany, fetchall) after the next query is executed, then I only open one cursor - it's like this: cr = c.cursor() try: cr.execute(query1) do stuff with cr.fetchone/many/all cr.execute(query2) ... finally: cr.close() As the DB-API indicates, if you want to manipulate more than one result set, you need more than one cursor. With PostgreSQL, my impression is that the intended way of using cursors is not entirely compatible with the DB-API: you declare cursors only when you know what the query will be, not in advance, and they can only be used with certain kinds of operations. As far as I recall, pyPgSQL supports cursors fairly transparently, albeit through various ad-hoc measures, whereas psycopg2 only does so for named cursors - a concept missing from the DB-API as far as I can see. The concept of cursor in MySQL is apparantly very different from what I originally thought. I always thought the cursor is the handler for a certain connection, and that you needed to commit before closing down this handler - else changes were automatically rolled back. It's easy to believe this, given the hierarchical nature of the API. However, cursors are just things which keep track of result sets, and I suppose that they are most useful when you perform a query which produces a large number of result rows, but where you only want to read a limited number of those rows at a time. Paul -- http://mail.python.org/mailman/listinfo/python-list
Re: Adding properties to an instance
Does this mean that __setattr__ incurs the same performance penalty that overriding __getattribute__ would? Not quite AFAICT - there's less going on here. Also, getting an attribute is (usually at least) more common than setting it. Possibly I can live with this because I think that most of what I'm doing is getting attributes, or modifying mutable ones, rather than setting them. Well... Using the __setattr__/__getattr__ hooks is IMHO the simplest solution that can possibly work - far simpler than your previous one at least. As far as I'm concerned, and unless some other point of your specs make this unusable or unpractical, I'd go for this solution first and run a couple benchs on real-life-or-close-to conditions to check if the performance hit is acceptable. I think you're right - I've just tried implementing a simple version of this in my code and it seems that in the time critical parts of it __setattr__ isn't called even once. So I think I'll go with this solution (after having run a few tests). Thanks for your suggestion! -- Dan -- http://mail.python.org/mailman/listinfo/python-list
Re: Server side cookie problems
On Feb 6, 8:00 pm, Gabriel Genellina [EMAIL PROTECTED] wrote: En Wed, 06 Feb 2008 15:27:53 -0200, rodmc [EMAIL PROTECTED] escribi�: Hi, I am trying to set a cookie on a client computer using the Cookie module however all I get is the text being printed in the browser window. Can anyone point me in the right direction so that the cookie def writetocookie(number): #writes the ID of the database entry to a cookie cookie[dataid]=number print Content-Type: text/html print print Set-Cookie: dataid=,cookie[dataid].value I presume this is not the correct way to write a cookie, the examples I have found online don't seem to provide much more information. I don't know either if this is the right way, but surely the Set-Cookie header must appear *before* the blank line; that blank line separates the headers from the response body. -- Gabriel Genellina Thanks, that seemed to work. rod -- http://mail.python.org/mailman/listinfo/python-list
Re: Using a class as a structure/container
[EMAIL PROTECTED] a écrit : (snip) Thanks for the information. The reason why I was taking this approach was more from a user interface perspective. What I have is a file that contains certain geometric objects, lets call them geo. Each geo object has 4 possible surfaces: You mean it has one of the 4 surfaces, or it has them all ? ps, ss, le, te. Each surface has x,y,z coordinates. It is not known apriori if any of these surfaces exist in the file. So I created a geo_reader class that is passed a filename in its argument list. It then parses the file, creating a container class for each geo object and assigning the name geo0, geo1, geo2, etc... as an attribute of the geo_reader class. You want an indexed ordered collection (ie: something like a list) here. The geo_reader class also stores global attributes concerning the file, i.e. the number of geo objects, a list handle this. etc... Then for each geo container I bind another container class for each surface that I find for each geo object, i.e. the ps, ss, le, te surfaces. Then the coordinates for each of the surfaces becomes an attribute of each of their corresponding containers. Err... Why don't you actually take time to write the Geo and Surface classes ? It will *really* save you time in the long run. I can also bind certain attributes to the container class to tell whether its a geo object or surface, etc. You definitively want to write the appropriate classes. I just didn't want the user to have to use the dictionary syntax like this: x_coords = my_geo['geo0']['ps']['x'] As far as I'm concerned, I'd use a list-like interface for my_geo, ie: my_geo[0].ps.x And I'd define the four surface attributes of the Geo object, default them to either None or a NullSurface object (whose x and y attribs have the None value). It just seems a little more natural to use the dot operator approach for users to interface with. wrt/ attribute access, yes, indeed. wrt/ what is clearly an ordered collection, there's already a well defined interface !-) And anyway, this doesn't mean you should not properly define your classes - this is no more complex than what you're doing here, and it will make your code *way* more readable, maintainable and usable - even for your users, since they'll be able to introspect your objects type, print the docstrings (if you write them of course), eventually use autocompletion (cf the rlcompleter module) etc. I wasn't aware of the Law of Demeter and I agree with all your concerns. I'm just not sure which one a user would rather interface with from the command line. The dot operators are quicker to type. Indeed. Now if you have such concern, why not go all the way ?-) My 2 cents -- http://mail.python.org/mailman/listinfo/python-list
index() of sequence type?
I see list has index member, but is there an index function that applies to any sequence type? If not, shouldn't there be? -- http://mail.python.org/mailman/listinfo/python-list
Re: Server side cookie problems
On Feb 7, 1:06 pm, rodmc [EMAIL PROTECTED] wrote: On Feb 6, 8:00 pm, Gabriel Genellina [EMAIL PROTECTED] wrote: En Wed, 06 Feb 2008 15:27:53 -0200, rodmc [EMAIL PROTECTED] escribi�: Hi, I am trying to set a cookie on a client computer using the Cookie module however all I get is the text being printed in the browser window. Can anyone point me in the right direction so that the cookie def writetocookie(number): #writes the ID of the database entry to a cookie cookie[dataid]=number print Content-Type: text/html print print Set-Cookie: dataid=,cookie[dataid].value I presume this is not the correct way to write a cookie, the examples I have found online don't seem to provide much more information. I don't know either if this is the right way, but surely the Set-Cookie header must appear *before* the blank line; that blank line separates the headers from the response body. -- Gabriel Genellina Thanks, that seemed to work. rod Also how do I find out if a cookie has expired? I have tried various methods but to no avail? Cheers, rod -- http://mail.python.org/mailman/listinfo/python-list
Re: Why does list have no 'get' method?
[EMAIL PROTECTED] a écrit : Steven D'Aprano: With the greatest respect, I think that if you think the second example is more clear, you're completely bonkers. *grins* No one is completely normal, I presume :-) I'd like to know what others think about it, about this anti-feature. s/anti// What I can say is that other computer languages too think that boolean operations must return boolean values only, Not quite. In C and a couple other langages, int 0 is false, anything else is true. In Lisp (and IIRC), an empty list is false, anything else is true. I'm sure someone else could come with more than a couple other non-cryptic langages that just don't have a proper boolean type. Using emptyness as a false value in boolean expressions is not that uncommon, and it has proven so far to be a working solution. Also, returning the tested object instead of a bool just makes sens to me. FWIW, booleans are a late addition to Python, and quite a couple persons where worried that it would only lead to confusion. -- http://mail.python.org/mailman/listinfo/python-list
Need Smart Phone with new features? please click here
www.enmac.com.hk GSM Mobile Phones, Digital iPods, Digital Clocks, Digital Pens, Digital Quran. Enjoy these products with Islamic Features (Complete Holy Quran with Text and Audio, Tafaseer books, Ahadees Books, Daily Supplications, Universal Qibla Direction, Prayer Timing and much more) visit our website for more information. -- http://mail.python.org/mailman/listinfo/python-list
Re: beginners help
2008/2/7, Guido van Brakel [EMAIL PROTECTED]: Hello I totally new to python and i'm doing a python course now. Maybe someone could help me a little bit here: I need to create this script. If i enter a center digit like 5 for example i need to create two vertical and horzitonal rows that looks like this. If i enter 6 it shows 6 six starts. How can i do this, because i don't have any clue. * * * * * * * * This would totally ruin the purpose of your course. Did you try anything at all ? Kind Regards, -- Guido van Brakel -- -- http://mail.python.org/mailman/listinfo/python-list -- -- Guilherme H. Polo Goncalves -- http://mail.python.org/mailman/listinfo/python-list
Re: index() of sequence type?
Neal Becker wrote: I see list has index member, but is there an index function that applies to any sequence type? Like this? def find_index(seq, value): try: find_index = seq.index except AttributeError: def find_index(value): for i,v in enumerate(seq): if v == value: return i raise ValueError(index(seq, x): x not in sequence) return find_index(value) If not, shouldn't there be? I don't see the need. Stefan -- http://mail.python.org/mailman/listinfo/python-list
Re: Looking for library to estimate likeness of two strings
At 14:01 Wed 06 Feb 2008, [EMAIL PROTECTED] wrote: Are there any Python libraries implementing measurement of similarity of two strings of Latin characters? I'm writing a script to guess-merge two tables based on people's names, which are not necessarily spelled the same way in both tables (especially the given names). I would like some function that would help me make the best guess. Many thanks in advance! I used difflib.get_close_matches for something similar: http://docs.python.org/lib/module-difflib.html HTH. -- Lee Capps Technology Specialist CTE Resource Center -- http://mail.python.org/mailman/listinfo/python-list
beginners help
Hello I totally new to python and i'm doing a python course now. Maybe someone could help me a little bit here: I need to create this script. If i enter a center digit like 5 for example i need to create two vertical and horzitonal rows that looks like this. If i enter 6 it shows 6 six starts. How can i do this, because i don't have any clue. * * * * * * * * Kind Regards, -- Guido van Brakel -- -- http://mail.python.org/mailman/listinfo/python-list
Re: Why not a Python compiler?
On Feb 5, 9:30 am, [EMAIL PROTECTED] wrote: I don't know the exact details but I think the issue is the dynamic nature of Python makes it impossible to correctly store the various types and changes into compiled code. Someone else will probably be able to provide a good reason as to why it isn't very feasible, nor a good idea. If you want to speed up your python look at Psyco. http://psyco.sourceforge.net/ Yeah, but exactly what features make it so hard to write a compiler for Python? Common Lisp seems like a language at least as dynamic as Python, e.g. you can change the type of objects at runtime, you can make changes to functions, you can change classes at runtime, you can add methods and generic functions (nb. these changes are reflected in existing objects), you have a metaobject protocol. Moreover, you have multimethods (in Python you don't, so it is one less thing to care). However, Common Lisp has a few decent compilers (at least two open source and two commercial). Google tells me that such arguments have been raised back in 2001 [1]. I can add from myself that today Python is much more similar to Common Lisp than in 2001. For example, multiple inheritance in Python = 2.3 behaves like in Dylan, which in turn behaves like CLOS with a twist. What is more, apparently there is a Python compiler via CL: CLPython (I don't have access to ACL, however, so I can't verify the claims of the authors). Finally, speaking of JIT compilers: recently has appeared something that looks like avery nice JIT compiler for Scheme, Ikarus [3]. Scheme is also quite dynamical, but is not OO, so I don't know how viable is the analogy. Of course, when writing Python extensions in C is fairly easy and when rewriting just the critical part of the code is enough to get acceptable performance, I really doubt I will see anybody willing to invest serious amounts of money and time into writing a native compiler for Python. Learning C cannot be so hard ;-). Also, this seems consistent with Python viewed as a glue between libraries written in C. Cheers, -- Richard BIG FAT DISCLAIMER: I DO NOT want to start a Python vs. Common Lisp and Scheme flame war. [1] http://mail.python.org/pipermail/python-list/2001-April/080394.html [2] http://common-lisp.net/project/clpython/ [3] http://www.cs.indiana.edu/~aghuloum/ikarus/ -- http://mail.python.org/mailman/listinfo/python-list
Re: beginners help
Guido van Brakel wrote: Hello I totally new to python and i'm doing a python course now. Maybe someone could help me a little bit here: I need to create this script. If i enter a center digit like 5 for example i need to create two vertical and horzitonal rows that looks like this. If i enter 6 it shows 6 six starts. How can i do this, because i don't have any clue. * * * * * * * * This list is not there to provide you with solutions to your homework. If you try and show us your efforts, or have otherwise concrete questions you certainly will get the help you want. Diez -- http://mail.python.org/mailman/listinfo/python-list
Re: Must COMMIT after SELECT
Paul Boddie wrote: On 7 Feb, 08:52, Frank Aune [EMAIL PROTECTED] wrote: On Wednesday 06 February 2008 16:16:45 Paul Boddie wrote: Really, the rule is this: always (where the circumstances described above apply) make sure that you terminate a transaction before attempting to read committed, updated data. How exactly do you terminate a transaction then?Do you terminate a transaction by closing the cursor? No, the transaction is controlled using the connection object in the DB-API, specifically by the commit and rollback methods. Would this indicate that for each query you perform against the db, you should: - Open cursor - Perform query - Close cursor I tend to open a separate cursor for each query whose result set I want to keep around. In other words, if I'm doing a number of queries whose results will not be manipulated via the DB-API (using fetchone, fetchmany, fetchall) after the next query is executed, then I only open one cursor - it's like this: cr = c.cursor() try: cr.execute(query1) do stuff with cr.fetchone/many/all cr.execute(query2) ... finally: cr.close() As the DB-API indicates, if you want to manipulate more than one result set, you need more than one cursor. Clearly you need multiple cursors if you want to be reading from the database on both cursors simultaneously. Like you, though, I tend to use a single cursor whenever I can get away with it (and now I think about it, that's probably because of the greater likelihood of seeing db consistency due to the read repeatability, though I can honestly say I hadn't really formalized that principle). With PostgreSQL, my impression is that the intended way of using cursors is not entirely compatible with the DB-API: you declare cursors only when you know what the query will be, not in advance, and they can only be used with certain kinds of operations. As far as I recall, pyPgSQL supports cursors fairly transparently, albeit through various ad-hoc measures, whereas psycopg2 only does so for named cursors - a concept missing from the DB-API as far as I can see. Yes, unfortunately the nomenclature of the DB API conflicts with that of SQL'S DECLARE CURSOR, where the named cursor is effectively a sequence of query results that (under certain isolation levels and patterns of usage) can reflect database changes as they occur. Different implementers have chosen different relationships between DB API cursors and SQL cursors since it was introduced in the SQL 92 standard. I believe, without documentary justification, that named cursors were introduced into SQL to support stored procedures, and therefore weren't intended to be used for queries whose results were communicated outside the server. MySQL (never the most reliable indication of standardized SQL), restricts them to use inside stored procedures and triggers. PostgreSQL makes them more generally available, and I suppose it is possible to use a DB API cursor to execute a FETCH statement to retrieve data from a SQL CURSOR though I have never tried to do it. SQL Server provides two types of cursor, one for use in the standard manner and one that conforms more closely with the ODBC cursor concept. I tend to treat the database as a purely relational store, and not use stored procedures, but this is a luxury not everyone can afford - it's just necessary to use them for efficiency reasons sometimes, though not in the applications I am mostly involved with. Consequently I haven't made much use of SQL CURSORs. The concept of cursor in MySQL is apparantly very different from what I originally thought. I always thought the cursor is the handler for a certain connection, and that you needed to commit before closing down this handler - else changes were automatically rolled back. It's easy to believe this, given the hierarchical nature of the API. However, cursors are just things which keep track of result sets, and I suppose that they are most useful when you perform a query which produces a large number of result rows, but where you only want to read a limited number of those rows at a time. That's true, and your remarks clarify cursor usage in the DB API very well. Most people most of the time tend to ignore the existence of cursor.fetchmany() in the DB API, despite the fact that it can provide huge efficiency gains over both .fetchone() (can slow processing by requiring too many database interactions per query) and .fetchmany() (which can generate large memory overhead in the case of huge result sets). regards Steve -- Steve Holden+1 571 484 6266 +1 800 494 3119 Holden Web LLC http://www.holdenweb.com/ -- http://mail.python.org/mailman/listinfo/python-list
Re: index() of sequence type?
Neal Becker wrote: I see list has index member, but is there an index function that applies to any sequence type? If not, shouldn't there be? Looks like an oversight to me as well, yes. The only difficult implementation would be the one for xrange, because you can't search but must compute the result - but that should be trivial. Diez -- http://mail.python.org/mailman/listinfo/python-list
Re: Why does list have no 'get' method?
Bruno Desthuilliers [EMAIL PROTECTED] wrote: Not quite. In C and a couple other langages, int 0 is false, anything else is true. Not just int, but all kinds of integers, as well as all kinds of floating point types and all kinds of pointers, with the value 0 are considered false. And structs and unions can't be used in a boolean context at all, and are thus neither true nor false. In Lisp (and IIRC), an empty list is false, anything else is true. There seems to be a language name missing from the parenthesis. Were you perhaps thinking of Scheme? If so, then no, in Scheme only #f is false, and the empty list () is considered true. -- Thomas Bellman, Lysator Computer Club, Linköping University, Sweden When C++ is your hammer, everything ! bellman @ lysator.liu.se looks like a thumb.! Make Love -- Nicht Wahr! -- http://mail.python.org/mailman/listinfo/python-list
Re: Looking for library to estimate likeness of two strings
[EMAIL PROTECTED] wrote: On Wed, 06 Feb 2008 17:32:53 -0600, Robert Kern wrote: Jeff Schwab wrote: ... If the strings happen to be the same length, the Levenshtein distance is equivalent to the Hamming distance. Is this really what the OP was asking for. If I understand it correctly, Levenshtein distance works out the number of edits required to transform the string to the target string. The smaller the more equivalent, but with the OP's problem I would expect table1 table2 brian briam erian I think the OP would like to guess at 'briam' rather than 'erian', but Levenstein would rate them equally good guesses? I know this is pushing it more toward phonetic alaysis of the words or something similar, and thats orders of magnitude more complex. just in case, http://www.linguistlist.org/sp/Software.html#97 might be a good place to start looking into it, along with the NLTK libraries here http://nltk.sourceforge.net/index.php/Documentation You could perhaps use soundex to try to choose between different possibilities with the same Levenshtein distance from the sample. Soundex by itself is horrible, but it might work as a prioritizer. regards Steve -- Steve Holden+1 571 484 6266 +1 800 494 3119 Holden Web LLC http://www.holdenweb.com/ -- http://mail.python.org/mailman/listinfo/python-list
Re: python beginner problem(?)
Steve Holden [EMAIL PROTECTED] wrote in message news:[EMAIL PROTECTED] Steve Holden wrote: Alan Illeman wrote: Win2k Pro - installed python: ok [...] = C:\Python25\Lib\site-packages\pythonwin\pywin\mfc\object.py: 23: DeprecationWarning: raising a string exception is deprecated raise win32ui.error, The MFC object has died. pwd=secret;database=master;uid=sa;server=mpilgrim = DiveIntoPython example 2.1 result: server=mpilgrim;uid=sa;database=master;pwd=secret ..which I realise is essentially the same (except for order). I haven't ever (not that I remember) installed MFC. Help! [...] I am hugely surprised to find that PythonWin apparently raises string exceptions: this is an old programming technique, which should have been removed from anything designed to run on Python 2.5. That is why you see the message: it's only a warning, so you can ignore it. I am copying Mark on this message in case he's unaware of the issue. [...] In a private reply Mark Hammond says he will fix this in the next release - thanks for the report! regards Steve -- Steve Holden+1 571 484 6266 +1 800 494 3119 Holden Web LLC http://www.holdenweb.com/ Thanks Steve for both your replies. Was (or is) python a piggyback for MFC? -- http://mail.python.org/mailman/listinfo/python-list
print 'hello' - SyntaxError: invalid syntax
I try to install Python in a Dell D620 with XP PRO version 5.1.2600 and I am getting this error. I assume that some dlls are missing but I installed form a fresh python-2.5.1.msi without errors msg. Thanks Roberto Python 2.5.1 (r251:54863, Apr 18 2007, 08:51:08) [MSC v.1310 32 bit (Intel)] on win32 Type help, copyright, credits or license for more information. import this File stdin, line 1 import this ^ SyntaxError: invalid syntax 2 + 2 File stdin, line 1 2 + 2 ^ SyntaxError: invalid syntax print 'Hello' File stdin, line 1 print 'Hello' ^ SyntaxError: invalid syntax help File stdin, line 1 help ^ SyntaxError: invalid syntax -- http://mail.python.org/mailman/listinfo/python-list
Re: Why does list have no 'get' method?
Thomas Bellman a écrit : Bruno Desthuilliers [EMAIL PROTECTED] wrote: (snip) In Lisp (and IIRC), an empty list is false, anything else is true. There seems to be a language name missing from the parenthesis. Yes, sorry - I was thinking of OCaml and/or Haskell, but couldn't remember which so I cout this out but forgot the (and IIRC). -- http://mail.python.org/mailman/listinfo/python-list
Re: Must COMMIT after SELECT
On 7 Feb, 14:29, Steve Holden [EMAIL PROTECTED] wrote: That's true, and your remarks clarify cursor usage in the DB API very well. Most people most of the time tend to ignore the existence of cursor.fetchmany() in the DB API, despite the fact that it can provide huge efficiency gains over both .fetchone() (can slow processing by requiring too many database interactions per query) and .fetchmany() fetchall ;-) (which can generate large memory overhead in the case of huge result sets). Indeed. I managed to run into a problem with DB-API-compliant code and psycopg2 in this respect: select a large number of rows, watch PostgreSQL do its work, see the Python process suck down the entire result set. It's a situation reminiscent of that incident involving a python and an alligator in the Florida swamps, but where the alligator survives. I don't use psycopg2 at the moment, but I did patch it to allow more transparent usage of cursors, and there's an unapplied patch for this floating around in the bug tracker. Lately, I've been using pyPgSQL instead and not really doing huge selects from Python code anyway, but I'm still using fetchmany for one or two things. Paul -- http://mail.python.org/mailman/listinfo/python-list
Re: Why not a Python compiler?
Ryszard Szopa wrote: Of course, when writing Python extensions in C is fairly easy and when rewriting just the critical part of the code is enough to get acceptable performance, I really doubt I will see anybody willing to invest serious amounts of money and time into writing a native compiler for Python. Learning C cannot be so hard ;-). Sure! Learning English also is not too hard. So everyone should be capable of writing poetry of Shakespeare niveau. Regards, Björn -- BOFH excuse #69: knot in cables caused data stream to become twisted and kinked -- http://mail.python.org/mailman/listinfo/python-list
Re: Why does list have no 'get' method?
Wildemar Wildenburger wrote: Arnaud Delobelle wrote: Personally, between * foo if foo else bar * foo or bar I prefer the second. Maybe it could be spelt * foo else bar ? How about val = foo rather than bar If that is not clear and obvios, I don't know what is. ;) Even clearer: ASSIGN foo IF foo HAS A VALUE, OTHERWISE bar, TO val Ahh, the joys of the COmmon Business Oriented Language. regards Steve -- Steve Holden+1 571 484 6266 +1 800 494 3119 Holden Web LLC http://www.holdenweb.com/ -- http://mail.python.org/mailman/listinfo/python-list
Re: Why does list have no 'get' method?
Arnaud Delobelle wrote: Personally, between * foo if foo else bar * foo or bar I prefer the second. Maybe it could be spelt * foo else bar ? How about val = foo rather than bar If that is not clear and obvios, I don't know what is. ;) /W -- http://mail.python.org/mailman/listinfo/python-list
Re: socket script from perl - python
kettle wrote:
Hi I have a socket script, written in perl, which I use to send
audio data from one server to another. I would like to rewrite
this in python so as to replicate exactly the functionality of the
perl script, so as to incorporate this into a larger python
program. Unfortunately I still don't really have the hang of
socket programming in python.
Socket programming in Python is just like socket programming in C. I
suppose with Perl it's the same.
# pack $length as a 32-bit network-independent long
my $len = pack('N', $length);
[...]
I've used python's socket library to connect to the server, and
verified that the first piece of data'r' is read correctly, the
sticking point seems to be the $len variable. I've tried using
socket.htonl() and the other less likely variants, but nothing
seem to produce the desired result, which would be to have the
server-side message print the same 'length' as the length printed
by the client.
Try struct.calcsize.
Regards,
Björn
--
BOFH excuse #88:
Boss' kid fucked up the machine
--
http://mail.python.org/mailman/listinfo/python-list
Re: Must COMMIT after SELECT
On 2008-02-07 16:46, Carsten Haese wrote: On Thu, 2008-02-07 at 16:33 +0100, M.-A. Lemburg wrote: mxODBC has support for named cursors that you can later use for positioned updates. Since we're on the topic of shameless plugs, InformixDB has this feature, too :) However, it's usually better to do updates in the classical way, ie. by referencing a primary key. That depends on the notion of better. It's entirely possible that a WHERE CURRENT OF cursor clause finds the row in question faster than even an indexed access using a primary key could. If you're processing a single row, I would agree that using an update cursor is overkill, but if you're processing a large number of rows, using an update cursor might be beneficial. Agreed. This approach is also very useful if you have to do extra analysis of the rows in question *outside* the database, before selecting them for update. -- Marc-Andre Lemburg eGenix.com Professional Python Services directly from the Source (#1, Feb 07 2008) Python/Zope Consulting and Support ...http://www.egenix.com/ mxODBC.Zope.Database.Adapter ... http://zope.egenix.com/ mxODBC, mxDateTime, mxTextTools ...http://python.egenix.com/ Try mxODBC.Zope.DA for Windows,Linux,Solaris,MacOSX for free ! eGenix.com Software, Skills and Services GmbH Pastor-Loeh-Str.48 D-40764 Langenfeld, Germany. CEO Dipl.-Math. Marc-Andre Lemburg Registered at Amtsgericht Duesseldorf: HRB 46611 -- http://mail.python.org/mailman/listinfo/python-list
Re: Multiple interpreters retaining huge amounts of memory
On Feb 2, 10:32 pm, Graham Dumpleton [EMAIL PROTECTED] wrote: The multi interpreter feature has some limitations, but if you know what you are doing and your application can be run within those limitations then it works fine. I've been wondering about this for a while. Given the severe limitations of it, what are the use cases where multiple interpreters do work? All I can think of is that it keeps separate copies of loaded python modules, but since you shouldn't be monkey-patching them anyway, why should you care? -- http://mail.python.org/mailman/listinfo/python-list
Re: Why does list have no 'get' method?
Wildemar Wildenburger wrote: Arnaud Delobelle wrote: Personally, between * foo if foo else bar * foo or bar I prefer the second. Maybe it could be spelt * foo else bar ? How about val = foo rather than bar If that is not clear and obvios, I don't know what is. ;) /W Excellent suggestion, and obviously its semantics should be: val = foo if bar else foo and so, some might argue for: val = foo despite bar which would allow more aggressive short-circuiting. However, I'm not sure how useful this is in practice. M -- http://mail.python.org/mailman/listinfo/python-list
Re: embedded python in c++ packaging
Furkan Kuru wrote: Hello, I have been developing an application in C++ that embeds Python interpreter. It takes advantage of too many modules from Python. When I want to package this application, I need to add too many files (.pyc) from Python/lib folder together with Python25.dll. Is there a way to pack these .pyc files to a zip file and redirect Python25.dll to that zip file? That is effectively what py2exe does with the modules required by the main application. It takes all the required modules and puts them in a library.zip file. You might take a look at how it does it. j -- http://mail.python.org/mailman/listinfo/python-list
Re: IronPython vs CPython: faster in 1.6 times?
On Feb 6, 1:54 pm, Stefan Behnel [EMAIL PROTECTED] wrote: Isaac Gouy wrote: On Feb 5, 11:47 am, Stefan Behnel [EMAIL PROTECTED] wrote: [EMAIL PROTECTED] schrieb: Mike C. Fletcher: Not sure if Mono also provides a speedup. There is a set of good benchmarks here, the answer is negative: http://shootout.alioth.debian.org/sandbox/benchmark.php?test=all〈... This doesn't look like Mono to me: IronPython 1.1 (1.1) on .NET 2.0.50727.42 Stefan Have you actually looked at the version string from IronPython-1.1- Bin.zip running on Mono? Why? Would that look like Mono? :) Stefan Why? Because then you'd be doing more than expressing your personal ignorance. -- http://mail.python.org/mailman/listinfo/python-list
Re: embedded python in c++ packaging
The Python byte-code files are already pretty dense, so compressing them further is unlikely to work if you try to put them in a zip. WMM On Feb 7, 2008 11:39 AM, Furkan Kuru [EMAIL PROTECTED] wrote: Hello, I have been developing an application in C++ that embeds Python interpreter. It takes advantage of too many modules from Python. When I want to package this application, I need to add too many files (.pyc) from Python/lib folder together with Python25.dll. Is there a way to pack these .pyc files to a zip file and redirect Python25.dll to that zip file? Thanks in advance. -- Furkan Kuru -- http://mail.python.org/mailman/listinfo/python-list -- http://warrenmyers.com God may not play dice with the universe, but something strange is going on with the prime numbers. --Paul Erdős It's not possible. We are the type of people who have everything in our favor going against us. --Ben Jarhvi, Short Circuit 2 -- http://mail.python.org/mailman/listinfo/python-list
Re: re question
On Feb 7, 10:38 am, Amit Gupta [EMAIL PROTECTED] wrote:
Python'ites
I searched around google to find the answer to this question, but I
can't:
I have a named regexp : x = re.compile((?Pme[a-z]+))
What I want is an iterator, that can return me both the groupname
and the matched string, e.g:
m = x.search(aa)
Somehow, I want to get
{me : aa}, either as dictionary or some iterable form.
All I found is, I need to know the groupname to get the
corresponding match. Any help is appreciated.
A
Got It. re.search() has a function groupdict(), doing precisely that.
--
http://mail.python.org/mailman/listinfo/python-list
MyHDL project!!
sir, Is there still a possibility to collaborate??? David Blubaugh -Original Message- From: Blubaugh, David A. Sent: Friday, February 01, 2008 10:44 AM To: 'chewie54' Cc: 'python-list@python.org' Subject: MyHDL project ! Dan, I would be honored to start a project such as that in mind. How do we begin ?? David Blubaugh -Original Message- From: chewie54 [mailto:[EMAIL PROTECTED] Sent: Thursday, January 31, 2008 9:34 PM To: python-list@python.org Subject: Re: Will Python on day replaceMATLAB? I have been evaluating the python environment ever more closer. I believe I can interface python with a development environment known as the ImpulseC environment. The ImpulseC environment develops C to VHDL for FPGA development. I would especially love to interface Python with ImpulseC and the graphing capabilities of GNU Plot and SciPy in order to recreate a VHDL development environment that will be just as capable as a $50,000 dollar Matlab to VHDL toolbox. This is also a part of my Masters thesis. Is anyone willing to help in this endeavor? David Blubaugh Why not use MyHDL which is written in Python and translates to Verilog. I assume ImpulseC is a commercial product and costs a log. MyHDL is free. If you have any interests in combining MyHDL with SciPy and NumPy I would be interested in getting involved. Dan Fabrizio This e-mail transmission contains information that is confidential and may be privileged. It is intended only for the addressee(s) named above. If you receive this e-mail in error, please do not read, copy or disseminate it in any manner. If you are not the intended recipient, any disclosure, copying, distribution or use of the contents of this information is prohibited. Please reply to the message immediately by informing the sender that the message was misdirected. After replying, please erase it from your computer system. Your assistance in correcting this error is appreciated. -- http://mail.python.org/mailman/listinfo/python-list
re question
Python'ites
I searched around google to find the answer to this question, but I
can't:
I have a named regexp : x = re.compile((?Pme[a-z]+))
What I want is an iterator, that can return me both the groupname
and the matched string, e.g:
m = x.search(aa)
Somehow, I want to get
{me : aa}, either as dictionary or some iterable form.
All I found is, I need to know the groupname to get the
corresponding match. Any help is appreciated.
A
--
http://mail.python.org/mailman/listinfo/python-list
Setting up a new user and environment from within a python script
Hello, I have written a script that uses environment variables set during a particular users login in .bash_profile and .profile. I have changed to that users uid and gid in my python script using: import os os.setegid os.setgid os.seteuid os.setuid but I still am not picking up the needed environment. When I run: os.environ I can see that I still have the environment of the user that owns the python script. I would like to maintain the original script owner but somehow pick up the correct environment for the targeted user. Several options looked to create an environment in a sub-process which I don't think is the correct solution. I could of course cut and paste the values from .bash_profile .profile but figured there is probably a better, cleaner way to do the same. Searched this forum with no luck and checked several python references. What is the best practice to achieve this goal? Thanks, Henry Hollenberg -- http://mail.python.org/mailman/listinfo/python-list
Re: Why does list have no 'get' method?
On Feb 7, 12:15 pm, [EMAIL PROTECTED] wrote: On Feb 7, 11:01 am, Denis Bilenko [EMAIL PROTECTED] wrote: Steve Holden wrote: These versions differ with respect to treatment of blank lines, which indicates how easy it is to go astray in this kind of semantic optimization. Your example simply wouldn't work (though you could patch it up using if line is None. (despite the use of short-circuiting predicates). both examples show reduction by 3 lines. Perhaps so, but you have to realise that Python has never valued code compactness over clarity. I'm not sure that your democratic wish to ensure fairness to sequences will garner much support, interesting though it is in an academic sense. Thank you for the patch. My incentives are not academic though. I convinced that this line = self._buffer.get(self._bufindex) if line is None: self._bufindex += 1 self._lineno += 1 self._filelineno += 1 return line line = self.readline() is more clear than try: line = self._buffer[self._bufindex] except IndexError: pass else: self._bufindex += 1 self._lineno += 1 self._filelineno += 1 return line line = self.readline() I mentioned 3 lines reduction just because it is objective, while 'more clear' is subjective. Code snippets are again not equivalent, e.g. in the case when self._buffer[self._bufindex] exists and is equal to None. Although the author could probably make a guarantee that is never the case. This has been a pet peeve of mine too. So you are not completely crazy: http://aspn.activestate.com/ASPN/Cookbook/Python/Recipe/269484 There is a discussion about precisely this by Alex Martelli in the printed version of the Python cookbook (2nd edition). I don't share the opinion but I am not going to fight the core Python developers over it. I don't think it is worth the effort. Python is so smooth already, there has to be some excuse to add some cute hack to your program once in a while :-). dict(enumerate(lst)).get(i,default) for example although not very efficient, looks cute. I think I like it better than my own solution. Actually to clarify, I think this is more useful for tuples (or tuple like structures) than lists per se. On homogeneous lists I usually iterate. It is on heterogeneous that I want to extract specific fields that might be optional. -- http://mail.python.org/mailman/listinfo/python-list
Re: Is there a way to use .NET DLL from Python
Huayang Xia wrote:
What's the difference between .NET DLL and normal C DLL? Do you mean
after clr.AddReference('ClassLibrary1'), there is no need to import
ClassLibrary1?
A normal DLL and an assembly DLL share only the header. The rest is
totally different. You can see the DLL as a container for the CIL code.
clr.AddReference('ClassLibrary1') makes the namespaces of the
ClassLibrary1 assembly available to IronPython and PythonDotNET. import
ClassLibrary1 imports the name space. You must import the assembly
before you can use its name spaces.
Christian
--
http://mail.python.org/mailman/listinfo/python-list
Re: socket script from perl - python
kettle [EMAIL PROTECTED] writes:
# pack $length as a 32-bit network-independent long
my $len = pack('N', $length);
[...]
the sticking point seems to be the $len variable.
Use len = struct.pack('!L', length) in Python. See
http://docs.python.org/lib/module-struct.html for details.
--
http://mail.python.org/mailman/listinfo/python-list
Re: getting all user defined attributes of a class
On Feb 7, 12:28 am, grflanagan [EMAIL PROTECTED] wrote: On Feb 6, 11:07 pm, Amit Gupta [EMAIL PROTECTED] wrote: Hi How do I get user defined attributes of a class? e.g Class A(object) : self.x = 1 -- I want something like: for userattrib in A.getAllUserAttribute() : print userattrib [..] HTH Gerard Thanks. What I found is: If I call iterate over the __dict__ of the instance of the class, I only get user-atttributes and not built-in attributes. I have an instance of that class, anyway, so this will do. However, I wonder if I am getting just lucky and this might change in future. In that regard the solution provides by all posters above might well be more robust. A -- http://mail.python.org/mailman/listinfo/python-list
Re: brain stuck. whats occurring here?
On Feb 7, 11:38 am, [EMAIL PROTECTED] wrote: Hallo, I'm after [[[],[],[],[],[]],[[],[],[],[],[]],[[],[],[],[],[]],[[],[],[],[],[]],[[],[],[],[],[]]] (NxN 'grid', 5x5 in that example, and while typing this up i figured out how to get it, but I'm still not sure what _was_ happening) I'm trying a=[] row=[ [] for n in range(0,10) ] a.extend(row[:]) a [[], [], [], [], [], [], [], [], [], []] a[0].extend(row[:]) a [[[...], [], [], [], [], [], [], [], [], []], [], [], [], [], [], [], [], [], []] why isnt that last a [[[...]],[],[],[],[],[],[],[],[],[]] Puzzled :) I don't see why you should get either. Especially considering this behaviour: a=[] row=[ [] for n in range(0,10) ] a.extend(row[:]) a [[], [], [], [], [], [], [], [], [], []] a[0].extend(row[:]) a [[[...], [], [], [], [], [], [], [], [], []], [], [], [], [], [], [], [], [], []] a[0][0][0][0][0][0][0][0][0][0][0][0][0][0] [[...], [], [], [], [], [], [], [], [], []] a=[] row=[ [] for n in range(0,10) ] a.extend(row[:]) a [[], [], [], [], [], [], [], [], [], []] Bug in IDLE? Matt. -- This message and any attachments (the message) is intended solely for the addressees and is confidential. If you receive this message in error, please delete it and immediately notify the sender. Any use not in accord with its purpose, any dissemination or disclosure, either whole or partial, is prohibited except formal approval. The internet can not guarantee the integrity of this message. BNP PARIBAS (and its subsidiaries) shall (will) not therefore be liable for the message if modified. Do not print this message unless it is necessary, consider the environment. - Ce message et toutes les pieces jointes (ci-apres le message) sont etablis a l'intention exclusive de ses destinataires et sont confidentiels. Si vous recevez ce message par erreur, merci de le detruire et d'en avertir immediatement l'expediteur. Toute utilisation de ce message non conforme a sa destination, toute diffusion ou toute publication, totale ou partielle, est interdite, sauf autorisation expresse. L'internet ne permettant pas d'assurer l'integrite de ce message, BNP PARIBAS (et ses filiales) decline(nt) toute responsabilite au titre de ce message, dans l'hypothese ou il aurait ete modifie. N'imprimez ce message que si necessaire, pensez a l'environnement. -- http://mail.python.org/mailman/listinfo/python-list
Re: Why not a Python compiler?
On 2008-02-06, Gary Duzan [EMAIL PROTECTED] wrote: In article [EMAIL PROTECTED], Grant Edwards [EMAIL PROTECTED] wrote: On 2008-02-06, Reedick, Andrew [EMAIL PROTECTED] wrote: One demerit has been marked against your geek card for missing an obvious science pun. Additionally, your membership to the Star Trek Lifestyle Adventure Club has been put on probationary status for the next twelve parsecs. Ouch. Two demerits for using the distance unit parsec in a context where a quantity of time was required. No demerits for Andrew; it is a Star Wars reference, which is quite on topic for this subthread. http://starwars.wikia.com/wiki/Kessel_Run Silly me. I wonder if George Lucas intended it as a joke or if he thought a parsec was a unit of time. -- Grant Edwards grante Yow! Clear the laundromat!! at This whirl-o-matic just had visi.coma nuclear meltdown!! -- http://mail.python.org/mailman/listinfo/python-list
Re: Why not a Python compiler?
Hallöchen! Grant Edwards writes: On 2008-02-06, Gary Duzan [EMAIL PROTECTED] wrote: In article [EMAIL PROTECTED], Grant Edwards [EMAIL PROTECTED] wrote: [...] Ouch. Two demerits for using the distance unit parsec in a context where a quantity of time was required. No demerits for Andrew; it is a Star Wars reference, which is quite on topic for this subthread. http://starwars.wikia.com/wiki/Kessel_Run Silly me. I wonder if George Lucas intended it as a joke or if he thought a parsec was a unit of time. The latter because it was corrected in the novelization. Tschö, Torsten. -- Torsten Bronger, aquisgrana, europa vetus Jabber ID: [EMAIL PROTECTED] (See http://ime.webhop.org for further contact info.) -- http://mail.python.org/mailman/listinfo/python-list
Re: Is there a way to use .NET DLL from Python
On Feb 7, 2:35 pm, Luis M. González [EMAIL PROTECTED] wrote:
On 7 feb, 05:52, Fuzzyman [EMAIL PROTECTED] wrote:
Luis M. González wrote:
On 6 feb, 21:17, Fuzzyman [EMAIL PROTECTED] wrote:
On Feb 6, 9:59 pm, Luis M. Gonz�lez [EMAIL PROTECTED] wrote:
On Feb 6, 6:27 pm, Huayang Xia [EMAIL PROTECTED] wrote:
Hello All,
I have several .NET DLL (I have no source code for them), is there
anyway to use them from python instead of from C#.
Thanks,
Huayang
I used to put my .dll files into the .DLL folder, so I could simply
import them as I would with any other python module.
But since I started using Ironpython 2.0 Alpha* this doesn't work
anymore...
Any hint?
The rule is probably still that the DLLs must be in a directory on
sys.path for the interpreter to find them. Try adding the directory
containing the assemblies to sys.path and see if you can add
references to them.
Michael Foordhttp://www.manning.com/foord
Luis
I tried adding the directory to sys.path.
Still not working...
import sys
sys.path.append('C:\Documents and
Settings\luismg\Escritorio\IronPython-2.0A
8\DLLs')
from ClassLibrary1 import *
Traceback (most recent call last):
File , line unknown, in ##235
File , line unknown, in _stub_##2
ImportError: No module named ClassLibrary1
You need to add references to assemblies before you can import from
the namespaces they contain.
import clr
clr.AddReference('ClassLibrary1')
HTH
Fuzzymanhttp://www.manning.com/foord
Oh, I know what you mean.
But that was exactly the reason for having a .DLLs folder, isn't it?
When you place an assembly into this folder, you avoid having to write
this boilerplate code, and simply import the assembly as you would
with a normal python module. At least, that´s how it worked in
previous versions...
No. You have always had to add references to assemblies before being
able to use the namespaces they contain. You even have to do this with
C# in Visual Studio.
Michael
http://www.manning.com/foord
--
http://mail.python.org/mailman/listinfo/python-list
Re: Looking for library to estimate likeness of two strings
En Thu, 07 Feb 2008 13:25:14 -0200, [EMAIL PROTECTED] [EMAIL PROTECTED] escribió: Many thanks for the excellent leads. I've also found several functions to find phonetic similarity between English names: the mentioned above soundex, then, also, one called metaphone. I'm now thinking of the best way to use some combination of these functions. You may be interested in this article which discusses some techniques used to match similar records: Record Linkage: A Machine Learning Approach, A Toolbox, and A Digital Government Web Service (2003) Mohamed G. Elfeky, Vassilios S. Verykios, Ahmed K. Elmagarmid, Thanaa M. Ghanem, Ahmed R. Huwait. http://citeseer.ist.psu.edu/elfeky03record.html -- Gabriel Genellina -- http://mail.python.org/mailman/listinfo/python-list
Re: Is there a way to use .NET DLL from Python
What's the difference between .NET DLL and normal C DLL? Do you mean
after clr.AddReference('ClassLibrary1'), there is no need to import
ClassLibrary1?
--
http://mail.python.org/mailman/listinfo/python-list
brain stuck. whats occurring here?
Hallo, I'm after [[[],[],[],[],[]],[[],[],[],[],[]],[[],[],[],[],[]],[[],[],[],[],[]],[[],[],[],[],[]]] (NxN 'grid', 5x5 in that example, and while typing this up i figured out how to get it, but I'm still not sure what _was_ happening) I'm trying a=[] row=[ [] for n in range(0,10) ] a.extend(row[:]) a [[], [], [], [], [], [], [], [], [], []] a[0].extend(row[:]) a [[[...], [], [], [], [], [], [], [], [], []], [], [], [], [], [], [], [], [], []] why isnt that last a [[[...]],[],[],[],[],[],[],[],[],[]] Puzzled :) Matt. -- This message and any attachments (the message) is intended solely for the addressees and is confidential. If you receive this message in error, please delete it and immediately notify the sender. Any use not in accord with its purpose, any dissemination or disclosure, either whole or partial, is prohibited except formal approval. The internet can not guarantee the integrity of this message. BNP PARIBAS (and its subsidiaries) shall (will) not therefore be liable for the message if modified. Do not print this message unless it is necessary, consider the environment. - Ce message et toutes les pieces jointes (ci-apres le message) sont etablis a l'intention exclusive de ses destinataires et sont confidentiels. Si vous recevez ce message par erreur, merci de le detruire et d'en avertir immediatement l'expediteur. Toute utilisation de ce message non conforme a sa destination, toute diffusion ou toute publication, totale ou partielle, est interdite, sauf autorisation expresse. L'internet ne permettant pas d'assurer l'integrite de ce message, BNP PARIBAS (et ses filiales) decline(nt) toute responsabilite au titre de ce message, dans l'hypothese ou il aurait ete modifie. N'imprimez ce message que si necessaire, pensez a l'environnement. -- http://mail.python.org/mailman/listinfo/python-list
Re: a trick with lists ?
S�� schrieb: I've found some class on the Net which takes basically this form : ## class Foo: def __init__(self): self.tasks = [] ... def method1(self): tasks = [] while True: ... append/pop elements into/from tasks ... if condition : break self.tasks[:] = tasks return ## What I do not fully understand is the line self.tasks[:] = tasks. Why does the guy who coded this did not write it as self.tasks = tasks? What is the use of the [:] trick ? It changes the list in-place. If it has been given to other objects, it might require that. Diez -- http://mail.python.org/mailman/listinfo/python-list
Re: Why does list have no 'get' method?
On Feb 7, 11:01 am, Denis Bilenko [EMAIL PROTECTED] wrote: Steve Holden wrote: These versions differ with respect to treatment of blank lines, which indicates how easy it is to go astray in this kind of semantic optimization. Your example simply wouldn't work (though you could patch it up using if line is None. (despite the use of short-circuiting predicates). both examples show reduction by 3 lines. Perhaps so, but you have to realise that Python has never valued code compactness over clarity. I'm not sure that your democratic wish to ensure fairness to sequences will garner much support, interesting though it is in an academic sense. Thank you for the patch. My incentives are not academic though. I convinced that this line = self._buffer.get(self._bufindex) if line is None: self._bufindex += 1 self._lineno += 1 self._filelineno += 1 return line line = self.readline() is more clear than try: line = self._buffer[self._bufindex] except IndexError: pass else: self._bufindex += 1 self._lineno += 1 self._filelineno += 1 return line line = self.readline() I mentioned 3 lines reduction just because it is objective, while 'more clear' is subjective. Code snippets are again not equivalent, e.g. in the case when self._buffer[self._bufindex] exists and is equal to None. Although the author could probably make a guarantee that is never the case. This has been a pet peeve of mine too. So you are not completely crazy: http://aspn.activestate.com/ASPN/Cookbook/Python/Recipe/269484 There is a discussion about precisely this by Alex Martelli in the printed version of the Python cookbook (2nd edition). I don't share the opinion but I am not going to fight the core Python developers over it. I don't think it is worth the effort. Python is so smooth already, there has to be some excuse to add some cute hack to your program once in a while :-). dict(enumerate(lst)).get(i,default) for example although not very efficient, looks cute. I think I like it better than my own solution. -- http://mail.python.org/mailman/listinfo/python-list
Re: python beginner problem(?)
Steve Holden [EMAIL PROTECTED] wrote in message news:[EMAIL PROTECTED] Alan Illeman wrote: Thanks Steve for both your replies. Was (or is) python a piggyback for MFC? You are supposed to be able to access the MFC classes through PythonWin, but I have never personally bothered because MFC is too horrible to tangle with. regards Steve That's a relief; I always hated MFC. Thanks. -- http://mail.python.org/mailman/listinfo/python-list
Re: Distinguishing between functions and methods in a decorator.
Berteun Damman wrote: Hello, I was wondering a bit about the differences between methods and functions. I have the following: def wrap(arg): print type(arg) return arg class C: def f(): pass @wrap def g(): pass def h(): pass print type(C.f) print type(h) Which gives the following output: type 'function' type 'instancemethod' type 'function' The first line is caused by the 'wrap' function of course. I had expected the first line to be 'instancemethod' too. So, I would guess, these methods of C are first created as functions, and only then become methods after they are 'attached' to some classobj. (You can do that yourself of course, by saying, for example, C.h = h, then the type of C.h is 'instancemethod' too.) Why does the wrapping occur before the function is 'made' into an instancemethod? Because a decorator could choose to return any function-object as it likes, see this example: def bar(self): print bar def makebar(f): return bar class Foo(object): @makebar def baz(self): pass foo = Foo() foo.baz() So you can't decide if a function is an instancemethod until the very last moment. Diez -- http://mail.python.org/mailman/listinfo/python-list
Distinguishing between functions and methods in a decorator.
Hello, I was wondering a bit about the differences between methods and functions. I have the following: def wrap(arg): print type(arg) return arg class C: def f(): pass @wrap def g(): pass def h(): pass print type(C.f) print type(h) Which gives the following output: type 'function' type 'instancemethod' type 'function' The first line is caused by the 'wrap' function of course. I had expected the first line to be 'instancemethod' too. So, I would guess, these methods of C are first created as functions, and only then become methods after they are 'attached' to some classobj. (You can do that yourself of course, by saying, for example, C.h = h, then the type of C.h is 'instancemethod' too.) Why does the wrapping occur before the function is 'made' into an instancemethod? The reason for asking is that I would like to differentiate between wrapping a function and an instancemethod, because in the latter case, the first parameter will be the implicit 'self', which I would like to ignore. However, when the wrapping occurs, the method still looks like a function. Berteun -- http://mail.python.org/mailman/listinfo/python-list
Re: Why not a Python compiler?
Jean-Paul Calderone wrote: On Thu, 07 Feb 2008 11:03:12 +0100, Stefan Behnel [EMAIL PROTECTED] wrote: Take a look at Cython. It's an optimising Python-to-C compiler for writing Python extensions. So you can basically take a Python module and compile it to C code that runs against the CPython runtime. http://cython.org/ It's a not-quite-Python-to-C compiler. Ok, there are differences. For example, you can't define functions dynamically (it doesn't currently support closures anyway). But it already supports a much wider subset of the language than Pyrex originally did. For example, you can use list comprehensions and Python 3 keyword-only arguments in function signatures. I would expect it would compile quite a lot of Python code out there without or with only minor modifications. I don't think it is an optimizing compiler either. Can you provide a reference for this? It optimises a lot of common patterns into very fast sequences of Python API calls (or even generates specialised non-API code for them). It also generates optimised runtime code for special cases based on the type of an object (e.g. if the object you iterate turns out to be a list, it uses fast list API calls in loops, and a standard iterator otherwise). So the generated code is usually much faster than what Pyrex gives you. Robert and I had an optimise session lately where we dropped the function call-overhead by some 20-50% (!) compared to the preceding Cython version (not even to Pyrex), just depending on the signature. I think that qualifies for an optimising compiler. Stefan -- http://mail.python.org/mailman/listinfo/python-list
Re: Looking for library to estimate likeness of two strings
2008/2/7, [EMAIL PROTECTED] [EMAIL PROTECTED]:
On Feb 7, 2:37 am, Daniel Fetchinson [EMAIL PROTECTED]
wrote:
Hi folks, just went through this thread and a related one from 2006
and I was wondering what the best solution is for using these string
metrics in a database search. If I want to query the database for a
string or something that is close to it (close being defined by one of
the string metrics discussed above) it seems I have to select each and
every word from the database and compare it with the query word which
is very ineffective.
I have never used sqlite database, but Postgres has a module that
implements levenshtein(), soundex() and metaphone() functions, so you
can do something like this:
SELECT * FROM s WHERE soundex(name) = soundex('john');
SELECT * FROM s WHERE difference(name, 'john') 2;
http://www.postgresql.org/docs/8.3/static/fuzzystrmatch.html
SQLite supports soundex, but it is disabled by default, you need to
compile it with -DSQLITE_SOUNDEX=1
--
http://mail.python.org/mailman/listinfo/python-list
--
-- Guilherme H. Polo Goncalves
--
http://mail.python.org/mailman/listinfo/python-list
Re: Is there a way to use .NET DLL from Python
Luis M. González wrote:
Oh, I know what you mean.
But that was exactly the reason for having a .DLLs folder, isn't it?
When you place an assembly into this folder, you avoid having to write
this boilerplate code, and simply import the assembly as you would
with a normal python module. At least, that´s how it worked in
previous versions...
In IronPython and with PythonDotNET you can import namespaces. Assembly
names and name spaces don't have to be related. E.g. ClassLibrary1.dll
may provide the namespace ClassLibA and ClassLibB.
clr.AddReference('ClassLibrary1') loads the assembly 'ClassLibrary1' and
makes all namespaces available to Python.
Christian
--
http://mail.python.org/mailman/listinfo/python-list
Re: Why not a Python compiler?
On Feb 7, 9:06 am, Steve Holden [EMAIL PROTECTED] wrote: Ryszard Szopa wrote: On Feb 5, 9:30 am, [EMAIL PROTECTED] wrote: I don't know the exact details but I think the issue is the dynamic nature of Python makes it impossible to correctly store the various types and changes into compiled code. Someone else will probably be able to provide a good reason as to why it isn't very feasible, nor a good idea. If you want to speed up your python look at Psyco.http://psyco.sourceforge.net/ Yeah, but exactly what features make it so hard to write a compiler for Python? [...] a. People tell me writing a compiler for Python is hard. b. It's certainly way to hard for me. c. But hey, I've heard about this neat language called Common Lisp that has a compiler. It looks a lot like Python. d. So why can't you brainboxes write a compiler for Python? Please tell me if I'm missing anything from this summary of your thought processes. The basic difference is in point c. Common Lisp was a standard arrived at by discussions including people who spent the 1970s and 1980s developing high-performance native-code Lisp compilers targeting conventional architectures (e.g. PDP-10, VAX, Sun workstations, etc.). Stuff that would be hard to support with compiled code on conventional CPUs was discouraged by the process. The semantics of the Common Lisp standard were developed with the needs of compilers in mind. CLOS is a very powerful object system, but the design was developed with compilation and efficiency concerns in mind. One major difference from Python OOP (as I understand it): CLOS methods are looked up by their global method name. Python methods (IIRC) are looked up in per-instance dictionaries. Redefining CLOS methods requires changing one method-dispatch cache, and is supported through a high-level interface, which a compiler can translate into the low-level implementation machinery. Python code can mash the dictionaries at will, because the low-level machinery is exposed. The details, if I have mis-stated them, are not as important as the principle of original design intent I am trying to illustrate. -- http://mail.python.org/mailman/listinfo/python-list
Re: socket script from perl - python
On Feb 7, 2008 9:39 AM, kettle [EMAIL PROTECTED] wrote:
f = open('/home/myuname/socket.wav','rb')
audio =
for line in f:
audio += line
I don't know anything about socket programming in python, but this bit
doesn't seem right for working on a binary file. You should just read
all of the data into audio in one go, like this:
f = open('/home/myuname/socket.wav','rb')
audio = f.read()
There's no need to iterate over the lines in the file, since it's
quite likely that there really aren't any 'lines' in a binary file.
--
Jerry
--
http://mail.python.org/mailman/listinfo/python-list
Re: Must COMMIT after SELECT
On 2008-02-07 14:29, Steve Holden wrote:
Paul Boddie wrote:
With PostgreSQL, my impression is that the intended way of using
cursors is not entirely compatible with the DB-API: you declare
cursors only when you know what the query will be, not in advance, and
they can only be used with certain kinds of operations. As far as I
recall, pyPgSQL supports cursors fairly transparently, albeit through
various ad-hoc measures, whereas psycopg2 only does so for named
cursors - a concept missing from the DB-API as far as I can see.
Yes, unfortunately the nomenclature of the DB API conflicts with that of
SQL'S DECLARE CURSOR, where the named cursor is effectively a sequence
of query results that (under certain isolation levels and patterns of
usage) can reflect database changes as they occur. Different
implementers have chosen different relationships between DB API cursors
and SQL cursors since it was introduced in the SQL 92 standard.
I believe, without documentary justification, that named cursors were
introduced into SQL to support stored procedures, and therefore weren't
intended to be used for queries whose results were communicated outside
the server.
Cursors defined using DECLARE CURSOR usually live in the
scope of the database engine. They are different from the cursors
defined and used with the database APIs.
MS even warns against mixing them:
http://msdn2.microsoft.com/en-us/library/aa172576(SQL.80).aspx
The Python DB-API is defined at the database API level, so the
same applies in the context of DB-API cursors.
In practice, I've not had problems with accessing named cursors
using DB-API cursors.
The main reason for the MS warning is that
cursors can be used for lots of interesting optimizations
such as auto-updating result sets and scrolling, positioned
updates or deletions, etc. The DB-API doesn't expose all these
nifty features, so doesn't easily run into trouble.
mxODBC has support for named cursors that you can later
use for positioned updates. You declare the name of the
cursor when creating it:
cursor1 = connection.cursor('mycursor')
cursor1.execute('select id, name, value from mytable')
# Position the mycursor on row 10
cursor1.fetchmany(10)
# Update row 10
cursor2 = connection.cursor()
cursor2.execute('update mytable set value = ? where current of mycursor')
cursor1.close()
cursor2.close()
However, it's usually better to do updates in the classical
way, ie. by referencing a primary key.
--
Marc-Andre Lemburg
eGenix.com
Professional Python Services directly from the Source (#1, Feb 07 2008)
Python/Zope Consulting and Support ...http://www.egenix.com/
mxODBC.Zope.Database.Adapter ... http://zope.egenix.com/
mxODBC, mxDateTime, mxTextTools ...http://python.egenix.com/
Try mxODBC.Zope.DA for Windows,Linux,Solaris,MacOSX for free !
eGenix.com Software, Skills and Services GmbH Pastor-Loeh-Str.48
D-40764 Langenfeld, Germany. CEO Dipl.-Math. Marc-Andre Lemburg
Registered at Amtsgericht Duesseldorf: HRB 46611
--
http://mail.python.org/mailman/listinfo/python-list
Re: Looking for library to estimate likeness of two strings
On Feb 7, 2:37 am, Daniel Fetchinson [EMAIL PROTECTED]
wrote:
Hi folks, just went through this thread and a related one from 2006
and I was wondering what the best solution is for using these string
metrics in a database search. If I want to query the database for a
string or something that is close to it (close being defined by one of
the string metrics discussed above) it seems I have to select each and
every word from the database and compare it with the query word which
is very ineffective.
I have never used sqlite database, but Postgres has a module that
implements levenshtein(), soundex() and metaphone() functions, so you
can do something like this:
SELECT * FROM s WHERE soundex(name) = soundex('john');
SELECT * FROM s WHERE difference(name, 'john') 2;
http://www.postgresql.org/docs/8.3/static/fuzzystrmatch.html
--
http://mail.python.org/mailman/listinfo/python-list
CVS access with Python
I have to design a Web-based CVS client. I could not find any module, cvs-binding in python. I have investigated all sort of Web Interface, including Sandweb, and ViewCVS etc. But these provide Read-only access and features. I need to provide almost all sort of basic features a developer frequently need in it. So please guide me. I found javacvs project in Netbeans project repository which seems a nice library, but since I am not a java programmer, this fails to me. Other problem is its implementation. Say, there is a repository of some projects with many modules. Now, when one developer wants to checkout, I can get the revision Sources to Web-server temporary sandbox, and create an archive (tar.gz/zip) and put that for downloading by the user. Since there is many-to-many relation between projects and developers, it will consume a lot of disk space on Web-server, creating 'n' copies of a single project for 'n' users, and assume all developers are checking out all sources. God knows. So is there any good implementation for such situation. -- -=Ravi=- -- http://mail.python.org/mailman/listinfo/python-list
ANN: ConfigObj 4.5.1 and validate 0.3.1
After one year and two days since the last release, there is a new release of ConfigObj. * ConfigObj 4.5.1 http://www.voidspace.org.uk/python/configobj.html * Validate 0.3.1 http://www.voidspace.org.uk/python/validate.html This release adds a few new features, plus has several bugfixes and minor performance improvements. Thanks to all those who gave feedback, reported bugs and provided patches. What are ConfigObj and Validate? = **ConfigObj** is a simple to use but powerful configuration file management library. Features include: * Nested sections to any depth * Unicode support * List and multiline values * Integrated with a powerful validation system - including automatic type checking/conversion - repeated sections - and allowing default values * All comments in a file are preserved when writing * The order of keys/sections is preserved * A powerful unrepr mode for storing basic datatypes **validate** is the module (optional) used for config file validation and type marshalling. It can be used outside of ConfigObj for matching string values against a text specification which also does type conversion. Changes in ConfigObj 4.5.1 Distribution updated to include version 0.3.1 of validate. This means that Unicode configspecs now work. ConfigObj will now guarantee that files will be written terminated with a newline. ConfigObj will no longer attempt to import the ``validate`` module, until/unless you call ``ConfigObj.validate`` with ``preserve_errors=True``. This makes it faster to import. New methods ``restore_default`` and ``restore_defaults``. ``restore_default`` resets an entry to its default value (and returns that value). ``restore_defaults`` resets all entries to their default value. It doesn't modify entries without a default value. You must have validated a ConfigObj (which populates the ``default_values`` dictionary) before calling these methods. BUGFIX: Proper quoting of keys, values and list values that contain hashes (when writing). When ``list_values=False``, values containing hashes are triple quoted. Added the ``reload`` method. This reloads a ConfigObj from file. If the filename attribute is not set then a ``ReloadError`` (a new exception inheriting from ``IOError``) is raised. BUGFIX: Files are read in with 'rb' mode, so that native/non-native line endings work! Minor efficiency improvement in ``unrepr`` mode. Added missing docstrings for some overridden dictionary methods. Added the ``reset`` method. This restores a ConfigObj to a freshly created state. Removed old CHANGELOG file. Changes in Validate 0.3.1 == BUGFIX: Unicode checks no longer broken. Improved performance with a parse cache. New ``get_default_value`` method. Given a check it returns the default value (converted to the correct type) or raises a ``KeyError`` if the check doesn't specify a default. Added 'tuple' check and corresponding 'is_tuple' function (which always returns a tuple). BUGFIX: A quoted 'None' as a default value is no longer treated as None, but as the string 'None'. BUGFIX: We weren't unquoting keyword arguments of length two, so an empty string didn't work as a default. BUGFIX: Strings no longer pass the 'is_list' check. Additionally, the list checks always return lists. A couple of documentation bug fixes. Removed CHANGELOG from module. Michael Foord -- http://mail.python.org/mailman/listinfo/python-list
Re: Looking for library to estimate likeness of two strings
On Feb 7, 6:11 am, Lee Capps [EMAIL PROTECTED] wrote: At 14:01 Wed 06 Feb 2008, [EMAIL PROTECTED] wrote: Are there any Python libraries implementing measurement of similarity of two strings of Latin characters? I'm writing a script to guess-merge two tables based on people's names, which are not necessarily spelled the same way in both tables (especially the given names). I would like some function that would help me make the best guess. Many thanks in advance! I used difflib.get_close_matches for something similar: http://docs.python.org/lib/module-difflib.html HTH. -- Lee Capps Technology Specialist CTE Resource Center Algorithms typically used for name comparisons include soundex, nysiis, and levenshtein distance. The last is more general and variations are used in spell checkers. You can probably Google for Python versions. You can find implementations of these comparison functions at www.spss.com/devcentral in the extendedTransforms.py module. (Requires a login but free). HTH, Jon Peck -- http://mail.python.org/mailman/listinfo/python-list
Re: index() of sequence type?
Neal Becker wrote: I see list has index member, but is there an index function that applies to any sequence type? If not, shouldn't there be? Hitler would doubtless have wanted one. regards Steve [who knows this is a futile and incorrect attempt to have this thread suffer from premature termination]. -- Steve Holden+1 571 484 6266 +1 800 494 3119 Holden Web LLC http://www.holdenweb.com/ -- http://mail.python.org/mailman/listinfo/python-list
Re: Why does list have no 'get' method?
Denis Bilenko wrote:
Tim Golden wrote:
Dodging your question slightly (and at the risk of teaching
my grandmother to suck eggs) I sometimes use this idiom for
checking params. Obviously it only goes so far, but it's
fairly compact:
Noddy example code
import os, sys
if __name__ == '__main__':
ARGS = None, DEV
filename, db = \
(j or i for i, j in map (None, ARGS, sys.argv[1:]))
print sys.argv
print filename, db
/code
Thank you for the example. It demonstrates perfectly how
much people miss this feature :)
Raymond Hettinger wrote:
At first blush that example would make it seem like a good idea, but I
don't see how the example could extend past the first index. If the
port argument is optional, how would you know the index position of
optional arguments to follow?
With a dictionary, one could plausibly write:
host = d.get('host', 'http://example.com')
port = d.get('port', 8080)
path = d.get('path', '/')
But would this make sense with a list:
host = s.get(0, 'http://example.com')
port = d.get(1, 8080)
path = d.get(2, '/')
If positions 0 and 1 are optional, how do you expect to know whether
path is going to be at position 2? This problem doesn't exist with
dictionaries because the presence or absence of optional entries does
not affect the key reference to other entries. Accordingly, I
wouldn't expect that dict.get() would have a parallel list.get() with
plausible use cases.
If you want to fill position 2, then positions 0 and 1 are mandatory.
It is the simplest possible option parsing, I didn't said it was the
most flexible :)
But perhaps it was a wrong example altogether.
Consider a couple more snippets, unrelated to command-line options.
(found by searching 'IndexError' in the python standard library)
this snippet from cmd.py:
try:
return self.completion_matches[state]
except IndexError:
return None
transforms into
return self.completion_matches.get(state)
another one from fileinput.py
try:
line = self._buffer[self._bufindex]
except IndexError:
pass
else:
self._bufindex += 1
self._lineno += 1
self._filelineno += 1
return line
line = self.readline()
becomes
line = self._buffer.get(self._bufindex)
if line:
self._bufindex += 1
self._lineno += 1
self._filelineno += 1
return line
line = self.readline()
These versions differ with respect to treatment of blank lines, which
indicates how easy it is to go astray in this kind of semantic
optimization. Your example simply wouldn't work (though you could patch
it up using if line is None. (despite the use of short-circuiting
predicates).
both examples show reduction by 3 lines.
Perhaps so, but you have to realise that Python has never valued code
compactness over clarity.
There's nothing dictionary-specific in 'get', it is
just a special use-case of '__getitem__' that is needed frequently.
Since list has '__getitem__' it deserves to have 'get' too.
I'm not sure that your democratic wish to ensure fairness to sequences
will garner much support, interesting though it is in an academic sense.
regards
Steve
--
Steve Holden+1 571 484 6266 +1 800 494 3119
Holden Web LLC http://www.holdenweb.com/
--
http://mail.python.org/mailman/listinfo/python-list
Re: Why does list have no 'get' method?
[EMAIL PROTECTED] wrote: Steven D'Aprano: With the greatest respect, I think that if you think the second example is more clear, you're completely bonkers. *grins* It's amusing how often with the greatest respect is used to preface a statement that clearly implies very little respect at all. Though, for what it's worth, I agree with Steven here. No one is completely normal, I presume :-) I'd like to know what others think about it, about this anti-feature. What I can say is that other computer languages too think that boolean operations must return boolean values only, so I am not alone in my folly :-) Other languages do indeed refuse the temptation to short-circuit, but that doesn't mean that Python is wrong to do so. It's a design choice, and while you are free to disagree with it I imagine you would be pissing in the wind in attempting to get a change like that into Python 3. Most people like the semantics of and and or as they are. no-more-normal-than-anyone-else-ly y'rs - steve -- Steve Holden+1 571 484 6266 +1 800 494 3119 Holden Web LLC http://www.holdenweb.com/ -- http://mail.python.org/mailman/listinfo/python-list
Re: Why not a Python compiler?
Ryszard Szopa wrote: On Feb 5, 9:30 am, [EMAIL PROTECTED] wrote: I don't know the exact details but I think the issue is the dynamic nature of Python makes it impossible to correctly store the various types and changes into compiled code. Someone else will probably be able to provide a good reason as to why it isn't very feasible, nor a good idea. If you want to speed up your python look at Psyco. http://psyco.sourceforge.net/ Yeah, but exactly what features make it so hard to write a compiler for Python? [...] a. People tell me writing a compiler for Python is hard. b. It's certainly way to hard for me. c. But hey, I've heard about this neat language called Common Lisp that has a compiler. It looks a lot like Python. d. So why can't you brainboxes write a compiler for Python? Please tell me if I'm missing anything from this summary of your thought processes. regards Steve -- Steve Holden+1 571 484 6266 +1 800 494 3119 Holden Web LLC http://www.holdenweb.com/ -- http://mail.python.org/mailman/listinfo/python-list
Re: getting all user defined attributes of a class
On Feb 7, 1:42 pm, Amit Gupta [EMAIL PROTECTED] wrote:
Thanks. What I found is: If I call iterate over the __dict__ of the
instance of the class, I only get user-atttributes and not built-in
attributes. I have an instance of that class, anyway, so this will do.
However, I wonder if I am getting just lucky and this might change in
future. In that regard the solution provides by all posters above
might well be more robust.
Instances and classes have separate namespaces:
class X(object):
x = 1
def __init__(self):
self.y = 2
X().__dict__
{'y': 2}
X.__dict__
dictproxy object at 0xb7beab9c
X.__dict__.items()
[('__module__', '__main__'),
('__dict__', attribute '__dict__' of 'X' objects),
('x', 1),
('__weakref__', attribute '__weakref__' of 'X' objects),
('__doc__', None),
('__init__', function __init__ at 0xb7b5a454)]
And neither of those includes attributes defined in superclasses,
classes with __slots__, pseudo-attributes through __getattr__ and
possibly more I've missed.
George
--
http://mail.python.org/mailman/listinfo/python-list
Re: Dear David (was: MyHDL project)
On Feb 7, 4:48 pm, Blubaugh, David A. [EMAIL PROTECTED] wrote: sir, Is there still a possibility to collaborate??? David Blubaugh Dear David A. Blubaugh, Could you please make it a little less painful to read your messages? You're giving a bad name to Belcan, too. Daniel -- http://mail.python.org/mailman/listinfo/python-list
Re: a trick with lists ?
Tim Chase wrote: self.tasks[:] = tasks What I do not fully understand is the line self.tasks[:] = tasks. Why does the guy who coded this did not write it as self.tasks = tasks? What is the use of the [:] trick ? It changes the list in-place. If it has been given to other objects, it might require that. Nowadays it's stylistically better to write self.tasks = list(tasks) as it does just the same and makes it a little clearer what's going on Um...except it's not just the same? class Foo(object): def __init__(self, tasks): self.tasks1 = tasks self.todo1 = [self.tasks1, 42] self.tasks2 = tasks self.todo2 = [self.tasks2, 42] def new_tasks1(self, tasks): self.tasks1 = list(tasks) def new_tasks2(self, tasks): self.tasks2[:] = list(tasks) def __str__(self): return %r\n%r % (self.todo1, self.todo2) f = Foo([1,2,3]) f.new_tasks1([4,5,6]) print 'task1' print f # todo1/2 haven't been changed print 'task2' f.new_tasks2([4,5,6]) print f # both todo 1 2 have been changed Assignment to a name just rebinds that name. Assignment to a slice of a list replaces the contents in-place. [sigh] Right, I got the assignment the wrong way around (and clearly you can't put list(tasks) on the left-hand side of an assignment). Of course self.tasks = list(tasks) is equivalent to self.tasks = tasks[:] Thanks for pointing out my error. regards Steve -- Steve Holden+1 571 484 6266 +1 800 494 3119 Holden Web LLC http://www.holdenweb.com/ -- http://mail.python.org/mailman/listinfo/python-list
Re: Distinguishing between functions and methods in a decorator.
On Feb 7, 4:10 pm, Berteun Damman [EMAIL PROTECTED] wrote: Hello, I was wondering a bit about the differences between methods and functions. I have the following: def wrap(arg): print type(arg) return arg class C: def f(): pass @wrap def g(): pass def h(): pass print type(C.f) print type(h) Which gives the following output: type 'function' type 'instancemethod' type 'function' The first line is caused by the 'wrap' function of course. I had expected the first line to be 'instancemethod' too. So, I would guess, these methods of C are first created as functions, and only then become methods after they are 'attached' to some classobj. (You can do that yourself of course, by saying, for example, C.h = h, then the type of C.h is 'instancemethod' too.) Why does the wrapping occur before the function is 'made' into an instancemethod? Consider this: class Foo(object): ... def bar(self): pass ... Foo.bar unbound method Foo.bar Foo.__dict__['bar'] function bar at 0x7d5b0 It shows that when Foo.bar is evaluated, a new instancemethod object is created and that the 'bar' in the dictionary of 'Foo' is forever a plain function object. In fact, Foo.bar is equivalent to Foo.__dict__['bar'].__get__(None, Foo): Foo.__dict__['bar'].__get__(None, Foo) unbound method Foo.bar For more details you can read http://users.rcn.com/python/download/Descriptor.htm. The reason for asking is that I would like to differentiate between wrapping a function and an instancemethod, because in the latter case, the first parameter will be the implicit 'self', which I would like to ignore. However, when the wrapping occurs, the method still looks like a function. Berteun I think you're better off having a 'wrap' decorator for functions and a 'wrapmethod' decorator for methods. HTH -- Arnaud -- http://mail.python.org/mailman/listinfo/python-list
