Re: Python Imaging Library download link broken?
On 2009-06-29, Lawrence D'Oliveiro wrote: > "apt-get install python-imaging", anybody? C:\>apt-get install python-imaging Bad command or file name Nope. 01:10,501$ apt-get install python-imaging bash: apt-get: command not found Not quite; but, it does give me an idea. Debian usually keeps the origional source packages in their package repositories: 02:09,502,(1)$ wget http://ftp.de.debian.org/debian/pool/main/p/python-imaging/python1.1.5.orig.tar.gz => `python-imaging_1.1.5.orig.tar.gz' Resolving ftp.de.debian.org... 141.76.2.4 Connecting to ftp.de.debian.org|141.76.2.4|:80... connected. HTTP request sent, awaiting response... 200 OK Length: 429,570 (420K) [application/x-gzip] 100%[=>] 429,570 246.97K/s 02:09:43 (246.26 KB/s) - `python-imaging_1.1.5.orig.tar.gz' saved [429570/429570] 01:10,503$ Now that's the ticket! -- http://mail.python.org/mailman/listinfo/python-list
Re: validating HTTPS certificates?
On Fri, Jun 26, 2009 at 07:01:24PM +0200, Nobody wrote: > For a urllib-style interface, there's not much point in performing > verification after the fact. Either the library performs verification or > it doesn't. If it doesn't, you've just sent the (potentially confidential) > request to an unknown server; discovering this after the fact doesn't > really help. I was more thinking about supplying a/some CA certificate(s) and requiring that the site cert be valid (otherwise the connection should fail). This sounds very EAFP to me. Andras -- http://mail.python.org/mailman/listinfo/python-list
Re: Flexible warning system
On Sun, Jun 28, 2009 at 2:31 PM, Shrutarshi Basu wrote: > I'm writing a Python package where I have an underlying object model that is > manipulated by a runtime control layer and clients that interface with this > runtime. As I'm developing this i'm realizing that there are going to be a > number of places where the runtime might affect the object model in ways > that might not be immediately obvious to the user. I would like to have some > sort of warning system where the runtime can raise a warning and then the > clients can 'catch' those warnings and display them as they want to. Is > there some sort of a system that will operates like that or will I have to > roll my own? If I do need to roll my own, any ideas on how I should go about > it? I know that there is a warning module, but it seems to that all outputs > go to standard out which isn't what I want. > Thanks, > Basu > > Shrutarshi Basu > Computer Science, > Electrical and Computer Engineering, > Lafayette College, > The ByteBaker -- http://bytebaker.com > I just glanced at the docs for the warnings module and it seems like exactly what you're asking for, and you can change the default writing to stdout: "Warning messages are normally written to sys.stderr, but their disposition can be changed flexibly, from ignoring all warnings to turning them into exceptions. The disposition of warnings can vary based on the warning category (see below), the text of the warning message, and the source location where it is issued. Repetitions of a particular warning for the same source location are typically suppressed." - http://docs.python.org/library/warnings.html That said, why not just use exceptions? HTH, ~Simon -- http://mail.python.org/mailman/listinfo/python-list
Re: The Python Way for module configuration?
On Sun, Jun 28, 2009 at 1:22 PM, kj wrote: > In <[email protected]> Ben Finney > writes: > >>(Even if you don't want to receive email, could you please give your >>actual name in the ‘From’ field instead of just initials? It makes >>conversation less confusing.) > > I don't know why, but for as long as I can remember everyone calls > me kj, even my mom. My name is Keaweikekahialiʻiokamoku > Jallalahwallalruwalpindi > > kj > Now that's funny. +1 QotW ~SF -- http://mail.python.org/mailman/listinfo/python-list
Re: Good books in computer science?
On Sat, Jun 13, 2009 at 11:49 AM, koranthala wrote: > Hi all, > I do understand that this is not a python question and I apologize > for that straight up. > But I am a full time follower of this group and I have seen very > very brilliant programmers and solutions. > I also want to be a good programmer - so this question. > > Which are the classic books in computer science which one should > peruse? > I have (a) Code Complete (b) GOF (c) Art of programming. > > Art of programming was too tough for me - and I couldnt understand > much. The other two were good books - I understood and implemented > quite a bit from both. > What are the other books which I should peruse? > > Regards > K Knuth. I.e. "The Art of Computer Programming" by Prof. Knuth Your library should have a copy (it's a multi-volume opus), if not consider donating yours after you read them. -- http://mail.python.org/mailman/listinfo/python-list
Re: Fast Dictionary Access
Duncan Booth writes: > The suggested alternative: > >value = data.get(key, None) > > also has two dictionary lookups:... dg = data.get ... (inside loop): value = dg(key,None) -- http://mail.python.org/mailman/listinfo/python-list
Abort SimpleXMLRPCServer request prematurely?
With SimpleXMLRPCServer, if the server is taking too long, how can I use the client to kill the request and have the server abort prematurely? Thanks, Joseph -- http://mail.python.org/mailman/listinfo/python-list
pythonware.com down?
Hi, I am trying to get a hold of PIL, but pythonware.com seems to be down. Are there mirrors out there? I get a 502 Error "Bad Gateway - The proxy server received an invalid response from an upstream server." Does anyone else get that error? Thanks Casper -- http://mail.python.org/mailman/listinfo/python-list
Re: creating garbage collectable objects (caching objects)
Dave Angel wrote: > News123 wrote: >> Hi. >> >> I started playing with PIL. >> >> I'm performing operations on multiple images and would like compromise >> between speed and memory requirement. >> . . . >> >> The question, that I have is whether there is any way to tell python, >> that certain objects could be garbage collected if needed and ask python >> at a later time whether the object has been collected so far (image has >> to be reloaded) or not (image would not have to be reloaded) >> >> >> > You don't say what implementation of Python, nor on what OS platform. > Yet you're asking how to influence that implementation. Sorry my fault. I'm using C-python under Windows and under Linux > > In CPython, version 2.6 (and probably most other versions, but somebody > else would have to chime in) an object is freed as soon as its reference > count goes to zero. So the garbage collector is only there to catch > cycles, and it runs relatively infrequently. If CYthon frees objects as early as possible (as soon as the refcount is 0), then weakref wil not really help me. In this case I'd have to elaborate into a cache like structure. > > So, if you keep a reference to an object, it'll not be freed. > Theoretically, you can use the weakref module to keep a reference > without inhibiting the garbage collection, but I don't have any > experience with the module. You could start by studying its > documentation. But probably you want a weakref.WeakValueDictionary. > Use that in your third approach to store the cache. > > If you're using Cython or Jython, or one of many other implementations, > the rules will be different. > > The real key to efficiency is usually managing locality of reference. > If a given image is going to be used for many output files, you might > try to do all the work with it before going on to the next image. In > that case, it might mean searching all_creation_rules for rules which > reference the file you've currently loaded, measurement is key. Changing the order of the images to be calculated is key and I'm working on that. For a first step I can reorder the image creation such, that all outpout images, that depend only on one input image will be calculated one after the other. so for this case I can transform: # Slowest approach: for creation_rule in all_creation_rules(): img = Image.new(...) for img_file in creation_rule.input_files(): src_img = Image.open(img_file) img = do_somethingwith(img,src_img) # wrong indentation in OP img.save() into src_img = Image.open(img_file) for creation_rule in all_creation_rules_with_on_src_img(): img = Image.new(...) img = do_somethingwith(img,src_img) img.save() What I was more concerned is a group of output images depending on TWO or more input images. Depending on the platform (and the images) I might not be able to preload all two (or more images) So, as CPython's garbage collection takes always place immediately, then I'd like to pursue something else. I can create a cache, which caches input files as long as python leaves at least n MB available for the rest of the system. For this I have to know how much RAM is still available on a system. I'll start looking into this. thanks again N -- http://mail.python.org/mailman/listinfo/python-list
whizBase vs. Python
Hi, I am working on a study and I need expert opinion, I did not work with Python before, can anyone help me with a comparison between WhizBase (www.whizbase.com) and Python please. Thank you in advance, Ashraf Gheith -- http://mail.python.org/mailman/listinfo/python-list
Re: whizBase vs. Python
On Mon, Jun 29, 2009 at 1:24 AM, NurAzije wrote: > Hi, > I am working on a study and I need expert opinion, I did not work with > Python before, can anyone help me with a comparison between WhizBase > (www.whizbase.com) and Python please. Python is a popular, open-source, cross-platform, general-purpose programming language with a large standard library that is often used in web programming. Popular Python web frameworks include TurboGears and Django. WhizBase appears to be a proprietary, Windows-only, database-centric web macro language (or proper programming language perhaps, I didn't investigate deeply). Proprietary language = Vendor lock-in = Lose. Cheers, Chris -- http://blog.rebertia.com -- http://mail.python.org/mailman/listinfo/python-list
Re: No trees in the stdlib?
On Sun, 28 Jun 2009 20:54:11 -0700, Paul Rubin wrote: > João Valverde writes: >> Could you clarify what you mean by immutable? As in... not mutable? As >> in without supporting insertions and deletions? > > Correct. > >> That's has the same performance as using binary search on a sorted >> list. What's the point of using a tree for that? > > The idea is you can accomplish the equivalent of insertion or deletion > by allocating a new root, along with the path down to the place you > want to insert, i.e. O(log n) operations. So instead of mutating an > existing tree, you create a new tree that shares most of its structure > with the old tree, and switch over to using the new tree. The main issue here is that you need to be a bit smarter when it comes to "modifying" the tree. If you want to insert, delete or replace multiple elements, using repeated insert()s (etc) on the root is sub-optimal, as you will end up repeatedly duplicating the upper levels. Ideally you want to provide operations which will add/remove/replace multiple elements in a single traversal. -- http://mail.python.org/mailman/listinfo/python-list
ANN: eGenix mxODBC Connect 1.0.2 - Python Database Interface
ANNOUNCING eGenix.com mxODBC Connect Python Database Interface Version 1.0.2 Our new client-server product for connecting Python applications to relational databases - from all major platforms This announcement is also available on our web-site for online reading: http://www.egenix.com/company/news/eGenix-mxODBC-Connect-1.0.2-GA.html INTRODUCTION The mxODBC Connect Database Interface for Python allows users to easily connect Python applications to all major databases on the market today in a highly portable and convenient way. Unlike our mxODBC Python extension, mxODBC Connect is designed as client-server application, so you no longer need to find production quality ODBC drivers for all the platforms you target with your Python application. Instead you use an easy to install Python client library which connects directly to the mxODBC Connect database server over the network. This makes mxODBC Connect the ideal basis for writing cross-platform database programs and utilities in Python, especially if you run applications that need to communicate with databases such as MS SQL Server and MS Access, Oracle Database, IBM DB2 and Informix, Sybase ASE and Sybase Anywhere, MySQL, PostgreSQL, SAP MaxDB and many more, that run on Windows or Linux machines. By removing the need to install and configure ODBC drivers on the client side, mxODBC Connect greatly simplifies setup and configuration of database driven client applications, while at the same time making the network communication between client and database server more efficient and more secure. For more information, please see the product page: http://www.egenix.com/products/python/mxODBCConnect/ NEWS mxODBC Connect 1.0.2 is a patch-level release of our new mxODBC Connect product. * More Secure We have upgraded the server to our latest eGenix pyOpenSSL release 0.9.0-0.9.8k, which includes a number of important bug fixes to both pyOpenSSL and the used OpenSSL library. * More Robust Previous versions had a timeout issue that we have solved with this release. We have have also added a special case for shutting down the client with a broken server connection. In such cases, the client will no longer wait for a timeout and terminate much faster. * Ideal for Building Bridges mxODBC Connect Client now works on all major Python platforms. As a result, connecting from e.g. Linux or Mac OS X to an SQL Server database has never been easier. You can even keep the data sources you already have configured on your Windows machine and connect to them as if your application were running on the database server itself. UPGRADING You are encouraged to upgrade to this latest mxODBC Connect release. When upgrading, please always upgrade both the server and the client installations to the same version - even for patch level releases. Customers who have purchased mxODBC Connect 1.0 licenses can download and upgrade their existing installations without having to purchase new licenses or upgrades. The licenses will continue to work with version 1.0.2. Users of our stand-alone mxODBC product will have to purchase new licenses from our online shop in order to use mxODBC Connect. You can request 30-day evaluation licenses by visiting our web-site or writing to [email protected], stating your name (or the name of the company) and the number of eval licenses that you need. http://www.egenix.com/products/python/mxODBCConnect/#Evaluation DOWNLOADS The download archives as well as instructions for installation and configuration of the product can be found on the product page: http://www.egenix.com/products/python/mxODBCConnect/ If you want to try the package, jump straight to the download instructions: https://cms.egenix.com/products/python/mxODBCConnect/#Download Fully functional evaluation licenses for the mxODBC Connect Server are available free of charge: http://www.egenix.com/products/python/mxODBCConnect/#Evaluation mxODBC Connect Client is always free of charge. ___ SUPPORT Commercial support for this product is available from eGenix.com. Please see http://www.egenix.com/services/support/ for details about our support offerings. Enjoy, -- Marc-Andre Lemburg eGenix.com Professional Python Services directly from the Source (#1, Jun 29 2009) >>> Python/Zope Consulting and Support ...http://www.egenix.com/ >>> mxODBC.Zope.Database.Adapter ... http://zope.egenix.com/ >>> mxODBC, mxDateTime, m
Spam? Re: whizBase vs. Python
On 2009-06-29, NurAzije wrote: > Hi, > I am working on a study and I need expert opinion, I did not work with > Python before, can anyone help me with a comparison between WhizBase > (www.whizbase.com) and Python please. Given posts like: http://groups.google.com/group/Server-side-programing/browse_thread/thread/16cfcf58bc943a0/15840d85eedd952e#15840d85eedd952e is this just thinly veiled spam? The domain and the posting IP address are both out of Sarajevo, Bosnia. Obviously you alreadly know your product is nothing but a database macro processor. Python is a dynamic programming language and therefore far more capable. Your product is proprietary with less capability while Python is free and powerful. -- http://mail.python.org/mailman/listinfo/python-list
Re: urllib2.URLError: error using twill with python
On Jun 8, 12:58 pm, Steven D'Aprano wrote:
> On Mon, 08 Jun 2009 12:14:18 +0100, Mark Devine wrote:
> > Hi
> > I wonder if someone could point me in the right direction. I used the
> > following code to access gmail but I got a
> > urllib2.URLError:
> > error when I ran it. I have included the Traceback
>
> > import twill, string, os
> > b=twill.commands.get_browser()
> > b.set_agent_string("Mozilla/5.0 (Windows; U; Windows NT 5.1; en-GB;
> > rv:1.8.1.14) Gecko/20080404 Firefox/2.0.0.14") b.clear_cookies()
> > b.go('http://www.gmail.com')
> > f=b.get_form("1")
> > b.showforms()
> > f['Email']= email
> > f['Passwd'] =password
> > b.clicked(f, f)
> > b.submit()
>
> My bet is that the above is not the actual code you have run. I bet that
> the offending line is actually something like the following:
>
> b.go("'http://www.gmail.com";)
>
> Note that there is a single character difference.
>
> Consider the last two lines of the traceback:
>
> > raise URLError('unknown url type: %s' % type)
> > urllib2.URLError:
>
> It seems to be saying that the url type is 'http -- note the leading
> single quote.
>
> --
> Steven
Actually that is the exact code run from a python shell. Try it
yourself. I could not find anybody who successfully automated sending
a gmail through python with twill so if you know how I would greatly
appreciate any pointers.
--
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Timeout when connecting to sybase DBS
Hi All, I'm using the Sybase module for connecting and using a sybase DBS. When I try to connect when the DBS is down, it take approximately 4 minutes for the function (conn.ct_connect) to return with an error. I have looked for a timeout parameter to limit the 4 minutes to something more reasonable but couldn't find one. Can anyone please help? BTW, I'm using Sybase.connect(, , , datetime='auto') Thanks Gil -- http://mail.python.org/mailman/listinfo/python-list
Re: pep 8 constants
On Mon, 29 Jun 2009 06:07:19 +0100, Eric S. Johansson wrote: Rhodri James wrote: Reject away, but I'm afraid you've still got some work to do to convince me that PEP 8 is more work for an SR system than any other convention. [snip sundry examples] Yes, yes, recognition systems need both training and a careful selection of words to recognise to be effective. This I learned twenty years ago: if "cap" has a high failure rate, use something else. As far as I can tell, the only thing that you are even vaguely suggesting for convention use is underscores_with_everything. As promised, I laugh hollowly. -- Rhodri James *-* Wildebeest Herder to the Masses -- http://mail.python.org/mailman/listinfo/python-list
Re: pythonware.com down?
On 2009-06-29, C. Feldmann wrote: > I am trying to get a hold of PIL, but pythonware.com seems to be down. > Are there mirrors out there? > I get a 502 Error "Bad Gateway - The proxy server received an invalid > response from an upstream server." > Does anyone else get that error? Yes, more info below: http://groups.google.com/group/comp.lang.python/browse_frm/thread/2dbba1a1bd6ebee6/1d832c468efc3828?tvc=1#1d832c468efc3828 -- http://mail.python.org/mailman/listinfo/python-list
Re: validating HTTPS certificates?
On Mon, 29 Jun 2009 09:18:20 +0200, Andras.Horvath wrote: >> For a urllib-style interface, there's not much point in performing >> verification after the fact. Either the library performs verification or >> it doesn't. If it doesn't, you've just sent the (potentially confidential) >> request to an unknown server; discovering this after the fact doesn't >> really help. > > I was more thinking about supplying a/some CA certificate(s) and > requiring that the site cert be valid (otherwise the connection should > fail). This sounds very EAFP to me. This is easier to do with urllib2 than urllib. For urllib, you would need to either "fix" URLopener.open_https() or clone half of urllib (URLOpener and FancyURLOpener). For urllib2, you can use urllib2.install_opener() to replace the built-in HTTPSHandler with a subclass which performs validation. Validation should just be a matter of passing cert_reqs=CERT_REQUIRED and ca_certs= to ssl.wrap_socket(), then checking that SSLSocket.getpeercert() returns a non-empty dictionary. Note: the above is purely theoretical, based upon the (2.6) documentation and source code. I suggest that you verify it by connecting to a site with a bogus (e.g. self-signed) certificate and checking that it fails. -- http://mail.python.org/mailman/listinfo/python-list
Re: Advantages of Python (for web/desktop apps)?
On 28 Jun 2009 11:45:06 -0700 [email protected] (Aahz) wrote: > Perhaps I was unclear: I already knew what LMGTFY stands for, and I > think that using a site that requires JavaScript is anti-social. Maybe they could just redirect to Google if JS wasn't detected. regards, Marek -- http://mail.python.org/mailman/listinfo/python-list
Re: pythonware.com down?
On 29 Jun., 11:07, Tim Harig wrote: > On 2009-06-29, C. Feldmann wrote: > > > I am trying to get a hold of PIL, but pythonware.com seems to be down. > > Are there mirrors out there? > > I get a 502 Error "Bad Gateway - The proxy server received an invalid > > response from an upstream server." > > Does anyone else get that error? > > Yes, more info below: > > http://groups.google.com/group/comp.lang.python/browse_frm/thread/2db... yeah. need the windows version. guess this is another reason to add to my "why I should buy a mac" list. :) -- http://mail.python.org/mailman/listinfo/python-list
Re: [RELEASED] Python 3.1 final
On Sun, 28 Jun 2009 21:25:13 +, Benjamin Peterson wrote:
>> > The email module is, yes, broken. You can recover the bytestrings of
>> > command-line arguments and environment variables.
>>
>> 1. Does Python offer any assistance in doing so, or do you have to
>> manually convert the surrogates which are generated for unrecognised bytes?
>
> fs_encoding = sys.getfilesystemencoding()
> bytes_argv = [arg.encode(fs_encoding, "surrogateescape") for arg in sys.argv]
This results in an internal error:
> "\udce4\udceb\udcef\udcf6\udcfc".encode("iso-8859-1", "surrogateescape")
Traceback (most recent call last):
File "", line 1, in
SystemError: Objects/bytesobject.c:3182: bad argument to internal function
[FWIW, the error corresponds to _PyBytes_Resize, which has a
cautionary comment almost as large as the code.]
The documentation gives the impression that "surrogateescape" is only
meaningful for decoding.
>> 2. How do you do this for non-invertible encodings (e.g. ISO-2022)?
>
> What's a non-invertible encoding? I can't find a reference to the term.
One where different inputs can produce the same output.
--
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Re: pythonware.com down?
way back machine,comes to rescue. http://web.archive.org/web/20071011003451/www.pythonware.com/products/pil/index.htm On Mon, Jun 29, 2009 at 4:01 PM, C. Feldmann wrote: > On 29 Jun., 11:07, Tim Harig wrote: > > On 2009-06-29, C. Feldmann wrote: > > > > > I am trying to get a hold of PIL, but pythonware.com seems to be down. > > > Are there mirrors out there? > > > I get a 502 Error "Bad Gateway - The proxy server received an invalid > > > response from an upstream server." > > > Does anyone else get that error? > > > > Yes, more info below: > > > > http://groups.google.com/group/comp.lang.python/browse_frm/thread/2db... > > yeah. need the windows version. guess this is another reason to add to > my "why I should buy a mac" list. :) > -- > http://mail.python.org/mailman/listinfo/python-list > -- Thanks & Regards, Godson Gera http://godson.in -- http://mail.python.org/mailman/listinfo/python-list
Re: creating garbage collectable objects (caching objects)
News123 wrote: Dave Angel wrote: News123 wrote: Hi. I started playing with PIL. I'm performing operations on multiple images and would like compromise between speed and memory requirement. . . . The question, that I have is whether there is any way to tell python, that certain objects could be garbage collected if needed and ask python at a later time whether the object has been collected so far (image has to be reloaded) or not (image would not have to be reloaded) You don't say what implementation of Python, nor on what OS platform. Yet you're asking how to influence that implementation. Sorry my fault. I'm using C-python under Windows and under Linux In CPython, version 2.6 (and probably most other versions, but somebody else would have to chime in) an object is freed as soon as its reference count goes to zero. So the garbage collector is only there to catch cycles, and it runs relatively infrequently. If CYthon frees objects as early as possible (as soon as the refcount is 0), then weakref wil not really help me. In this case I'd have to elaborate into a cache like structure. So, if you keep a reference to an object, it'll not be freed. Theoretically, you can use the weakref module to keep a reference without inhibiting the garbage collection, but I don't have any experience with the module. You could start by studying its documentation. But probably you want a weakref.WeakValueDictionary. Use that in your third approach to store the cache. If you're using Cython or Jython, or one of many other implementations, the rules will be different. The real key to efficiency is usually managing locality of reference. If a given image is going to be used for many output files, you might try to do all the work with it before going on to the next image. In that case, it might mean searching all_creation_rules for rules which reference the file you've currently loaded, measurement is key. Changing the order of the images to be calculated is key and I'm working on that. For a first step I can reorder the image creation such, that all outpout images, that depend only on one input image will be calculated one after the other. so for this case I can transform: # Slowest approach: for creation_rule in all_creation_rules(): img = Image.new(...) for img_file in creation_rule.input_files(): src_img = Image.open(img_file) img = do_somethingwith(img,src_img) # wrong indentation in OP img.save() into src_img = Image.open(img_file) for creation_rule in all_creation_rules_with_on_src_img(): img = Image.new(...) img = do_somethingwith(img,src_img) img.save() What I was more concerned is a group of output images depending on TWO or more input images. Depending on the platform (and the images) I might not be able to preload all two (or more images) So, as CPython's garbage collection takes always place immediately, then I'd like to pursue something else. I can create a cache, which caches input files as long as python leaves at least n MB available for the rest of the system. For this I have to know how much RAM is still available on a system. I'll start looking into this. thanks again N As I said earlier, I think weakref is probably what you need. A weakref is still a reference from the point of view of the ref-counting, but not from the point of view of the garbage collector. Have you read the help on weakref module? In particular, did you read Pep 0205? http://www.python.org/dev/peps/pep-0205/ Object cache is one of the two reasons for the weakref module. -- http://mail.python.org/mailman/listinfo/python-list
Re: [RELEASED] Python 3.1 final
On Sun, 28 Jun 2009 14:36:37 +0200, Martin v. Löwis wrote:
>> That's a significant improvement. It still decodes os.environ and sys.argv
>> before you have a chance to call sys.setfilesystemencoding(), but it
>> appears to be recoverable (with some effort; I can't find any way to re-do
>> the encoding without manually replacing the surrogates).
>
> See PEP 383.
Okay, that's useful, except that it may have some bugs:
> r = "\udce4\udceb\udcef\udcf6\udcfc".encode("iso-8859-1", "surrogateescape")
Traceback (most recent call last):
File "", line 1, in
SystemError: Objects/bytesobject.c:3182: bad argument to internal function
Trying a few random test cases suggests that the ratio of valid to invalid
bytes has an effect. Strings which consist mostly of invalid bytes trigger
the error, those which are mostly valid don't.
The error corresponds to _PyBytes_Resize(), which has the following
words of caution in a preceding comment:
/* The following function breaks the notion that strings are immutable:
it changes the size of a string. We get away with this only if there
is only one module referencing the object. You can also think of it
as creating a new string object and destroying the old one, only
more efficiently. In any case, don't use this if the string may
already be known to some other part of the code...
Note that if there's not enough memory to resize the string, the original
string object at *pv is deallocated, *pv is set to NULL, an "out of
memory" exception is set, and -1 is returned. Else (on success) 0 is
returned, and the value in *pv may or may not be the same as on input.
As always, an extra byte is allocated for a trailing \0 byte (newsize
does *not* include that), and a trailing \0 byte is stored.
*/
Assuming that this gets fixed, it should make most of the problems with
3.0 solvable. OTOH, it wouldn't have killed them to have added e.g.
sys.argv_bytes and os.environ_bytes.
>> However, sys.std{in,out,err} are still created as text streams, and AFAICT
>> there's nothing you can do about this from within your code.
>
> That's intentional, and not going to change. You can access the
> underlying byte streams if you want to, as you could already in 3.0.
Okay, I've since been pointed to the relevant information (I was looking
under "File Objects"; I didn't think to look at "sys").
--
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Re: What does Guido want in a GUI toolkit for Python?
Martin v. Löwis wrote: I sorta' wish he'd just come out and say, "This is what I think would be suitable for a GUI toolkit for Python: ...". He is not in the business of designing GUI toolkits, but in the business of designing programming languages. So he abstains from specifying (or even recommending) a GUI library. What he makes clear is the point that Terry cites: no matter what the GUI toolkit is or what features it has - it should be simple to create GUIs, as simple as creating HTML. Tim Berners-Lee would laugh to hear html described as "simple." He was very frustrated with how long it took anyone to create a graphical toolkit to create webpages. So, what *does* Guido want in a GUI toolkit for Python? His concern really isn't what is in the toolkit, but what isn't. It must not require lots of lines of code to produce a simple GUI, it must not require specification of absolute coordinates, ... - you should be able to continue the list yourself. Regards, Martin -- http://mail.python.org/mailman/listinfo/python-list
python extend c++ module
I have written a c++ extend module and I use distutils to build.
setup.py
from distutils.core import setup, Extension
setup(name="noddy", version="1.0",
ext_modules=[
Extension("noddy3", ["noddy3.cpp", "a.cpp"])
])
I found it's quite strange when compiling. I didn't use extern "C" at all
, how can python get the right c++ funciton name without any compile error??
I found that it first use gcc to compile noddy3.cpp and then link by g++.
Could anyone explain what it's all about?
Thanks a lot!!
here is the compiling message.
---
running install
running build
running build_ext
building 'noddy3' extension
gcc -pthread -fno-strict-aliasing -DNDEBUG -g -fwrapv -O3 -Wall
-Wstrict-prototypes -fPIC -I/usr/local/include/python2.6 -c noddy3.cpp -o
build/temp.linux-i686-2.6/noddy3.o
cc1plus: warning: command line option "-Wstrict-prototypes" is valid for
Ada/C/ObjC but not for C++
g++ -pthread -shared build/temp.linux-i686-2.6/noddy3.o
build/temp.linux-i686-2.6/a.o -o build/lib.linux-i686-2.6/noddy3.so
running install_lib
copying build/lib.linux-i686-2.6/noddy3.so ->
/usr/local/lib/python2.6/site-packages
running install_egg_info
Removing /usr/local/lib/python2.6/site-packages/noddy-1.0-py2.6.egg-info
Writing /usr/local/lib/python2.6/site-packages/noddy-1.0-py2.6.egg-info
--
[1;36mâ»Post by [37mcommand [36mfrom [33m59-124-255-226.HINET-IP.[m
[1;36mèé¼ çé¦é¦ä¹³é
ªæ´[31mË[33mé»åä½åæ¬ç³»çµ±[31mË[32malexbbs.twbbs.org[31mË[37m140.113.166.7[m
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Re: Python Imaging Library download link broken?
In message , Tim Harig wrote: > On 2009-06-29, Lawrence D'Oliveiro > wrote: > >> "apt-get install python-imaging", anybody? > > C:\>apt-get install python-imaging > Bad command or file name Sounds more like broken OS with no integrated package management. -- http://mail.python.org/mailman/listinfo/python-list
Re: pythonware.com down?
On 2009-06-29, C. Feldmann wrote: > On 29 Jun., 11:07, Tim Harig wrote: >> On 2009-06-29, C. Feldmann wrote: >> >> > I am trying to get a hold of PIL, but pythonware.com seems to be down. >> > Are there mirrors out there? >> > I get a 502 Error "Bad Gateway - The proxy server received an invalid >> > response from an upstream server." >> > Does anyone else get that error? >> >> Yes, more info below: >> >> http://groups.google.com/group/comp.lang.python/browse_frm/thread/2db... > > yeah. need the windows version. guess this is another reason to add to > my "why I should buy a mac" list. :) The source is operating system agnostic. -- http://mail.python.org/mailman/listinfo/python-list
Re: pep 8 constants
Reject away, but I'm afraid you've still got some work to do to convince me that PEP 8 is more work for an SR system than any other convention. Name name higher than normal recognition error rate. can require multiple tries or hand correction MultiWordName mulitwordname very high error rate. many retries or hand hurting typing. multi_word_name multiwordname normal error rate (low), can need multiple tries or hand correction It sounds like the issue should be one of making your screen-reader smarter, not dumbing down Python conventions. I don't know what SR you're using (Jaws? Window Eyes? yasr? screeder? speakup? VoiceOver?) but it sounds like at least for the above cases, along with the PEP-8 MULTI_WORD_NAME constant convention, a simple regexp+transformation should be able to reprocess the input into something easier to handle/hear/understand. I'm not sure any/all of the previously-listed screen-readers give such regexp transformation control, but I would expect that at least the OSS ones (yasr, screeder, & speakup) it would be possible to add the feature if it doesn't already exist. For these three, you might ping the blinux mailing list to see if anybody there knows how to implement such transforms. StdlYCps sierra tango delta lima yankee charley papa sierra *** very high error rate *** search and replace for all instances with a x_y_z form name is recommended As for StuDlyCaps, it's hard on the seeing too, so I advocate a firm smack on the back of the head for those that prefer this abomination. :-) -tkc -- http://mail.python.org/mailman/listinfo/python-list
Running Invisible console Application
Hi, i have a console application that i want to ran (invisible) as a daemon, how can i do that? Thank you in advance. -- http://mail.python.org/mailman/listinfo/python-list
Re: python extend c++ module
æ¾å°èªå·±çä¸ç天 schrieb: > I found it's quite strange when compiling. I didn't use extern "C" at all > , how can python get the right c++ funciton name without any compile error?? > > I found that it first use gcc to compile noddy3.cpp and then link by g++. > > Could anyone explain what it's all about? The Python header files already contain the necessary extern "C" declarations. You can safely import the Python.h header file in a cpp file without an extern "C" block. Christian -- http://mail.python.org/mailman/listinfo/python-list
Re: [RELEASED] Python 3.1 final
Nobody nowhere.com> writes:
>
> This results in an internal error:
>
> > "\udce4\udceb\udcef\udcf6\udcfc".encode("iso-8859-1", "surrogateescape")
> Traceback (most recent call last):
> File "", line 1, in
> SystemError: Objects/bytesobject.c:3182: bad argument to internal function
Please report a bug on http://bugs.python.org
As for a bytes version of sys.argv and os.environ, you're welcome to propose a
patch (this would be a separate issue on the aforementioned issue tracker).
Thanks
Antoine.
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Re: [RELEASED] Python 3.1 final
Nobody writes: >On Sun, 28 Jun 2009 14:36:37 +0200, Martin v. Löwis wrote: >> See PEP 383. > > Okay, that's useful, except that it may have some bugs: > (...) > Assuming that this gets fixed, it should make most of the problems with > 3.0 solvable. OTOH, it wouldn't have killed them to have added e.g. > sys.argv_bytes and os.environ_bytes. That's hopeless to keep track of across modules if something modifies sys.argv or os.environ. If the current scheme for recovering the original bytes proves insufficient, what could work is a string type which can have an attribute with the original bytes (if the source was bytes). And/or sys.argv and os.environ maintaining the correspondence when feasible. Anyway, I haven't looked at whether any of this is a problem, so don't mind me:-) As long as it's definitely possible to tell python once and for all not to apply locales and string conversions, instead of having to keep track of an ever-expanding list of variables to tame it's bytes->character conversions (as happened with Emacs). -- Hallvard -- http://mail.python.org/mailman/listinfo/python-list
Re: No trees in the stdlib?
On Sat, 2009-06-27 at 06:03 +0100, João Valverde wrote: > To answer the question of what I need the BSTs for, without getting > into too many boring details it is to merge and sort IP blocklists, > that is, large datasets of ranges in the form of (IP address, IP > address, string). > As an anecdotal data point (honestly not trying to raise the "Python > is slow" strawman), I implemented the same algorithm in C and Python, > using pyavl. Round numbers were 4 mins vs 4 seconds, against Python > (plus pyavl). Out of interest, I recently wrote something similar that imported (a class of) snort rules for blacklisting ip traffic. I could only use the standard library. I ended up writing a simple tree using dict-like objects [1]. Afraid I haven't got a taught CS background to know the name of the structure. (note insertion wasn't the focus, and I didn't bother writing it to handle updates/merges - this is a quick script I run every now and then, so I'm sure it could be done better - I just liked having the standard dict interface for each node) I only had three levels of branching, using the first octet to branch at the root node, the second octet to branch as the second node, and the final two to branch at the third node's depth (since even then that's normally sparse relative to the first two nodes). It works well enough for me - I'm IO bound reading in ip addresses from logs to check against the blacklist, and there is a fair bit of other processing going on for each line. (Obviously I converted the ip addresses to integers before doing all this to avoid hashing strings etc) [1] (As rules could be for any subnet I overloaded some of the dict methods to check against rules on unusual subnets etc. before checking individual ips in the final part) > Even considering I'm a worse Python programmer than C > programmer, it's a lot. I know many will probably think I tried to do > "C in Python" but that's not the case, at least I don' t think so. > Anyway like I said, not really relevant to this discussion. > -- http://mail.python.org/mailman/listinfo/python-list
Re: [RELEASED] Python 3.1 final
2009/6/29 Antoine Pitrou :
> As for a bytes version of sys.argv and os.environ, you're welcome to propose a
> patch (this would be a separate issue on the aforementioned issue tracker).
But please be aware that such a proposal would have to consider:
1. That on Windows, the native form is the character version, and the
bytes version would have to address all the same sorts of encoding
issues that the OP is complaining about in the character versions. [1]
2. That the proposal address the question of how to write portable,
robust, code (given that choosing argv vs argv_bytes based on
sys.platform is unlikely to count as a good option...)
3. Why defining your own argv_bytes as argv_bytes =
[a.encode("iso-8859-1", "surrogateescape") for a in sys.argv] is
insufficient (excluding issues with bugs, which will be fixed
regardless) for the occasional cases where it's needed.
Before writing the proposal, the OP should probably review the
extensive discussions which can be found in the python-dev archives.
It would be wrong for people reading this thread to think that the
implemented approach is in any sense a "quick fix" - it's certainly a
compromise (and no-one likes all aspects of any compromise!) but it's
one made after a lot of input from people with widely differing
requirements.
Paul.
[1] And my understanding, from the PEP, is that even on POSIX, the
argv and environ data is intended to be character data, even though
the native C APIs expose a byte-oriented interface. So conceptually,
character format is "correct" on POSIX as well... (But I don't write
code for POSIX systems, so I'll leave it to the POSIX users to debate
this point further).
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Re: Good books in computer science?
This thread has thrown up some interesting suggestions but they all seem to fall into one of two categories: - the high-ground: Dijkstra, Knuth etc - the low-ground: write (any-which-how) a lot of code And both these 'grounds' seem to cause more argument and less suggestions for good books. Let me therefore try to find a middle-ground and make a suggestion that I used to make to my students when I taught them programming: Read the Python Manual -- specifically the library. It contains a fairly good conspectus of modern day IT/CS. Some examples of what I mean: Want to study TDD? Read unittest and doctest and then go on to reading (and practising) Kent Beck etc Want to get into unix system programming? Nothing like playing around with os.path and stat before burining your hands with C. Networking protocols? smtplib, urllib, ftplib etc Low level networking? socket, select etc Algorithms? Good to get your feet on the ground with timeit -- http://mail.python.org/mailman/listinfo/python-list
Re: Python Imaging Library download link broken?
On 2009-06-29, Lawrence D'Oliveiro wrote: > Sounds more like broken OS with no integrated package management. Package managers with dependency tracking were all the rage when I first started using Linux. So I tried Red Hat and everything worked great until the depency database corrupted itself. Since then, I have learned to install using whatever package manager but to upgrade or install new packages from source. -- http://mail.python.org/mailman/listinfo/python-list
Re: Running Invisible console Application
Elf Scripter wrote: Hi, i have a console application that i want to ran (invisible) as a daemon, how can i do that? Change the extension from ".py" to ".pyw". -- http://mail.python.org/mailman/listinfo/python-list
Re: Good books in computer science?
On Jun 29, 5:08 pm, rustom wrote: > > Want to study TDD? Read unittest and doctest and then go on to > reading (and practising) Kent Beck etc > Want to get into unix system programming? Nothing like playing around > with os.path and stat before burining your hands with C. > Networking protocols? smtplib, urllib, ftplib etc > Low level networking? socket, select etc > Algorithms? Good to get your feet on the ground with timeit Ive found twisted is a good excuse to study lot of CS arcana ranging from laziness of lambdas, event driven programming -- http://mail.python.org/mailman/listinfo/python-list
Re: fork, threads and proper closing
On 29 Giu, 07:10, OdarR wrote: > On 28 juin, 23:26, Tomasz Pajor wrote: > > > Hello, > > > Configuration is as follows. > > > I have a starter process which creates 3 sub processes (forks) and each > > of this processes creates a number of threads. > > Threads in that processes have semaphore so on KeyboardInterrupt without > > sending a sigterm to the subprocess i'm not able to close threads. > > Is there any work around? Can I somehow run join for the thread on > > keyboard interrupt? > > When creating a thread you can add a Queue parameter to communicate > with threads:http://docs.python.org/library/queue.html > easy and reliable. > > give them a "poison pill" in the queue: a recognizable object placed > on the queue that means "when you get this, stop." > This is the way I usually go, but it has one important limitation: if the thread is waiting for a blocking I/O operation to complete, like reading from a socket with no data or waiting for a locked resource (i.e. semaphore) to be unlocked, it will not service the queue and will not read the 'quit command' (the poison pill), and therefore will not quit until the blocking I/O terminates (and it could be never). ASAIK, there is no way - in python - to solve this. > Olivier Ciao FB -- http://mail.python.org/mailman/listinfo/python-list
Re: Python Imaging Library download link broken?
Whilst this is an interesting discussion about installers, I'm still trying to find a copy of PIL. Any ideas? -- http://mail.python.org/mailman/listinfo/python-list
problems with mysql db
here i have posted my code...plz tell why am i getting the error "int
argument required" on the hash marked line(see below) although i am
giving an int value
#the code
import os
import string
import MySQLdb
import stopcheck
conn = MySQLdb.connect(host='localhost',user='root',db='urdb')
def file_extractor(dir_name):
url_count = 0
for file in os.listdir(dir_name):
if(file[-4:] == '.txt'):
file_path = os.path.join(dir_name,file)
curse = conn.cursor()
url_count += 1
curse.execute("INSERT INTO URL_TABLE VALUES(%d,%s)",
(url_count,file_path)) #error
word_extractor(url_count,file_path)
def word_extractor(url_count,file):
fhandle = open(file)
line = fhandle.readline()
k=stopcheck.checker()
k.create()
while line:
words = line.split()
cursor = conn.cursor()
for word1 in words:
if word1 not in string.punctuation:
if (k.check(word1) is 0) and (word1[0:4] != 'http') :
word_count+=1
try:
cursor.execute("INSERT INTO word_table(id,word)
VALUES(%d,%s)" , (word_count,word1))
cursor.execute("INSERT INTO wordmatch
(word_id,url_id) values(%d,%d)",(word_count,url_count))
except MySQLdb.Error, e:
print "Error %d: %s" % (e.args[0], e.args[1])
line=fhandle.readline()
if __name__ == '__main__':
#url_count=0
#word_count=0
dir = os.path.join('D://','acm')
file_extractor(dir)
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Re: validating HTTPS certificates?
> validation. Validation should just be a matter of passing > cert_reqs=CERT_REQUIRED and ca_certs= to ssl.wrap_socket(), then checking > that SSLSocket.getpeercert() returns a non-empty dictionary. That'd be cool unless I can't use an already-open socket (by SSL, for verification) in any of the built-in HTTP engines, by the look of it. Andras -- http://mail.python.org/mailman/listinfo/python-list
Re: Advantages of Python (for web/desktop apps)?
In article <[email protected]>, Marek Kubica wrote: >On 28 Jun 2009 11:45:06 -0700 >[email protected] (Aahz) wrote: >> >> Perhaps I was unclear: I already knew what LMGTFY stands for, and I >> think that using a site that requires JavaScript is anti-social. > >Maybe they could just redirect to Google if JS wasn't detected. Exactly. They have chosen to be anti-social; therefore, I think anyone using lmgtfy.com is also anti-social. -- Aahz ([email protected]) <*> http://www.pythoncraft.com/ "as long as we like the same operating system, things are cool." --piranha -- http://mail.python.org/mailman/listinfo/python-list
Re: Python Imaging Library download link broken?
On 2009-06-29, peter wrote: > Whilst this is an interesting discussion about installers, I'm still > trying to find a copy of PIL. Any ideas? I alluded to a source version below. It will compile on Windows as well as on *nix. Google finds what looks like older versions here: http://sping.sourceforge.net/PIL/ -- http://mail.python.org/mailman/listinfo/python-list
Re: problems with mysql db
Hi,
use %s instead of %d in SQL statements, because (AFAIK) conversions
(including SQL escaping) from Python values to SQL values are done
before the % operator is called - that value is not a number by that
point.
I hope you understood it, sorry for my English :-) You can also check
MySQLdb module source, it's pretty clear.
PM
2009/6/29 golu :
> here i have posted my code...plz tell why am i getting the error "int
> argument required" on the hash marked line(see below) although i am
> giving an int value
> #the code
> import os
> import string
> import MySQLdb
> import stopcheck
> conn = MySQLdb.connect(host='localhost',user='root',db='urdb')
>
> def file_extractor(dir_name):
>url_count = 0
>
>for file in os.listdir(dir_name):
> if(file[-4:] == '.txt'):
>file_path = os.path.join(dir_name,file)
>curse = conn.cursor()
>url_count += 1
>curse.execute("INSERT INTO URL_TABLE VALUES(%d,%s)",
> (url_count,file_path)) #error
>word_extractor(url_count,file_path)
> def word_extractor(url_count,file):
>fhandle = open(file)
>line = fhandle.readline()
>k=stopcheck.checker()
>k.create()
>
>while line:
> words = line.split()
> cursor = conn.cursor()
> for word1 in words:
> if word1 not in string.punctuation:
>if (k.check(word1) is 0) and (word1[0:4] != 'http') :
> word_count+=1
> try:
>cursor.execute("INSERT INTO word_table(id,word)
> VALUES(%d,%s)" , (word_count,word1))
>cursor.execute("INSERT INTO wordmatch
> (word_id,url_id) values(%d,%d)",(word_count,url_count))
> except MySQLdb.Error, e:
> print "Error %d: %s" % (e.args[0], e.args[1])
> line=fhandle.readline()
>
> if __name__ == '__main__':
>#url_count=0
>#word_count=0
>
>dir = os.path.join('D://','acm')
>file_extractor(dir)
> --
> http://mail.python.org/mailman/listinfo/python-list
>
--
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Re: Running Invisible console Application
On Jun 29, 2009, at 7:28 AM, Elf Scripter wrote: Hi, i have a console application that i want to ran (invisible) as a daemon, how can i do that? Search the web for python + daemon. I found plenty of code, including mostly prewritten solutions, for my own work. Charles Yemans -- http://mail.python.org/mailman/listinfo/python-list
Re: creating garbage collectable objects (caching objects)
En Mon, 29 Jun 2009 08:01:20 -0300, Dave Angel escribió: News123 wrote: What I was more concerned is a group of output images depending on TWO or more input images. Depending on the platform (and the images) I might not be able to preload all two (or more images) So, as CPython's garbage collection takes always place immediately, then I'd like to pursue something else. I can create a cache, which caches input files as long as python leaves at least n MB available for the rest of the system. As I said earlier, I think weakref is probably what you need. A weakref is still a reference from the point of view of the ref-counting, but not from the point of view of the garbage collector. Have you read the help on weakref module? In particular, did you read Pep 0205? http://www.python.org/dev/peps/pep-0205/ You've misunderstood something. A weakref is NOT "a reference from the point of view of the ref-counting", it adds zero to the reference count. When the last "real" reference to some object is lost, the object is destroyed, even if there exist weak references to it. That's the whole point of a weak reference. The garbage collector isn't directly related. py> from sys import getrefcount as rc py> class X(object): pass ... py> x=X() py> rc(x) 2 py> y=x py> rc(x) 3 py> import weakref py> r=weakref.ref(x) py> r py> rc(x) 3 py> del y py> rc(x) 2 py> del x py> r (remember that getrefcount -as any function- holds a temporary reference to its argument, so the number it returns is one more than the expected value) Object cache is one of the two reasons for the weakref module. ...when you don't want the object to stay artificially alive just because it's referenced in the cache. But the OP wants a different behavior, it seems. A standard dictionary where images are removed when they're no more needed (or a memory restriction is fired). -- Gabriel Genellina -- http://mail.python.org/mailman/listinfo/python-list
Configuring Python for Tcl/Tk in UNIX
My goal is to use Tkinter on a ScientificLinux machine for a GUI I wrote. I installed Python 2.6.2, then built Tcl and Tk 8.5.7 from source. The final step is to configure Python 2.6 to run Tk. When I use the "make" command in the Python 2.6.2 directory, all is well until it tries to built _tkinter.so. I get an error as follows: *** WARNING: renaming "_tkinter" since importing it failed: libtk8.5.so: cannot open shared object file: No such file or directory. Failed to build the following modules: _tkinter I cannot use the default install location of /usr/bin, so I am trying to install into another directory. I line-by-line edited the setup.py file to point to the proper directory and I get the same error. Has anyone had a similar problem? Any advice is greatly appreciated. Thanks, Chris -- http://mail.python.org/mailman/listinfo/python-list
Re: problems with mysql db
En Mon, 29 Jun 2009 10:32:40 -0300, Petr Messner escribió: use %s instead of %d in SQL statements, because (AFAIK) conversions (including SQL escaping) from Python values to SQL values are done before the % operator is called - that value is not a number by that point. I hope you understood it, sorry for my English :-) You can also check MySQLdb module source, it's pretty clear. It's best to think of %s as just a marker; other adapters use ? or :3 for the same purpose, and other styles exist too. The fact that it's the same character used for formatting strings with the % operator is an unfortunate coincidence (or a very bad choice, I don't know). -- Gabriel Genellina -- http://mail.python.org/mailman/listinfo/python-list
Re: pep 8 constants
Peter Otten wrote: > Eric S. Johansson wrote: > >> MultiWordName mulitwordname >> very high error rate. many retries or hand hurting typing. > > Can you define macros in your speech recognition software? > > multiwordname > > might slightly lower the error rate. > Yes it would. I think it would be possible to specify a better grammar however. In the context of speech engine, if you know how the word is going to be used, (i.e. it's a method, it's a class, etc.) you can automatically do the transformation as part of the editors function. You need to know where you are in the syntax tree and that gives you enough knowledge to do the name transformation. When you stop thinking of speech recognition interactions as discrete macros or magic tricks, you can do a lot to accelerate coding. Fruit equals pear tree sub branch plus 5 The translator should know that the name on the lval is a variable (type signature determined later) and is terminated by the word equals (or =). The system would then apply the appropriate the name transformation. Continue on, equals would be transformed =, pear tree would be considered a complete name and based on whether it is a class definition or instance, would be transformed as a single name. Sub means there's an index here and would put the appropriate brackets between the expression branch (symbol terminated by plus) and 5 (symbol terminated by the end of line, fruit = pear_tree[branch+5] The next challenge comes in editing. It's fairly simple I would like to say "edit line [1*]" and put that line in an isolated buffer where I can edit the English form using all of the Select-and-Say controls. That should close the cycle from creation through editing. a small port of the development cycle. fyiw, the symbol trandformation code exists and has existed for almost 10 years. we need smart editing environments to make use of it. -- http://mail.python.org/mailman/listinfo/python-list
Python-URL! - weekly Python news and links (Jun 29)
QOTW: "Fortunately, I have assiduously avoided the real wor[l]d, and am happy to embrace the world from our 'bot overlords. Congratulations on another release from the hydra-like world of multi-head development." - Scott David Daniels, on release of 3.1 http://groups.google.com/group/comp.lang.python/msg/620d014fb549dbe6 A success story (involving a game server): http://groups.google.com/group/comp.lang.python/browse_thread/thread/11abba7af6e266b0/ Floats and Decimal objects demythified: http://groups.google.com/group/comp.lang.python/browse_thread/thread/77a9ecc671602e79/ Converting Python code to C/C++: how to do it, alternatives, and when it would be advisable: http://groups.google.com/group/comp.lang.python/browse_thread/thread/7152ab4f1c7dbced/ A generator expression declared at class scope: the namespace resolution rules aren't so intuitive: http://groups.google.com/group/comp.lang.python/browse_thread/thread/e1ab6188673fc623/ A look at 2.1 sample code shows how much (or how little) the language evolved over time: http://groups.google.com/group/comp.lang.python/browse_thread/thread/3e2139c2191bb191/ No "tree" data structure is available in the standard library - should one exist? http://groups.google.com/group/comp.lang.python/browse_thread/thread/c632217cfc7c7dcc/ Correctly implementing rich comparisons so 'set' membership works as expected: http://groups.google.com/group/comp.lang.python/browse_thread/thread/c0b1c58585c110eb/ Python threading and the GIL (again): http://groups.google.com/group/comp.lang.python/browse_thread/thread/9e22ab012388b538/ In ElementTree, XML() and fromstring() aren't the same thing: http://groups.google.com/group/comp.lang.python/browse_thread/thread/397f410b060afca2/ Open source Python projects that need help: http://groups.google.com/group/comp.lang.python/browse_thread/thread/667b9922a60ea836/ Meta issue: some posts appear to be missing, depending on where you read this (the mailing list, the newsgroup, the gmane gateway...) http://groups.google.com/group/comp.lang.python/browse_thread/thread/6cc24ff07dfd3afd/e7ad466392094c8c?#e7ad466392094c8c http://groups.google.com/group/comp.lang.python/browse_thread/thread/f67e695fa6364ec9/9174d8c5b4f07f74?#9174d8c5b4f07f74 [OT] Measuring Fractal Dimension (mad mathematicians only): http://groups.google.com/group/comp.lang.python/browse_thread/thread/a258b6c9005146c5/ Everything Python-related you want is probably one or two clicks away in these pages: Python.org's Python Language Website is the traditional center of Pythonia http://www.python.org Notice especially the master FAQ http://www.python.org/doc/FAQ.html PythonWare complements the digest you're reading with the marvelous daily python url http://www.pythonware.com/daily Just beginning with Python? This page is a great place to start: http://wiki.python.org/moin/BeginnersGuide/Programmers The Python Papers aims to publish "the efforts of Python enthusiasts": http://pythonpapers.org/ The Python Magazine is a technical monthly devoted to Python: http://pythonmagazine.com Readers have recommended the "Planet" sites: http://planetpython.org http://planet.python.org comp.lang.python.announce announces new Python software. Be sure to scan this newsgroup weekly. http://groups.google.com/group/comp.lang.python.announce/topics Python411 indexes "podcasts ... to help people learn Python ..." Updates appear more-than-weekly: http://www.awaretek.com/python/index.html The Python Package Index catalogues packages. http://www.python.org/pypi/ Much of Python's real work takes place on Special-Interest Group mailing lists http://www.python.org/sigs/ Python Success Stories--from air-traffic control to on-line match-making--can inspire you or decision-makers to whom you're subject with a vision of what the language makes practical. http://www.pythonology.com/success The Python Software Foundation (PSF) has replaced the Python Consortium as an independent nexus of activity. It has official responsibility for Python's development and maintenance. http://www.python.org/psf/ Among the ways you can support PSF is with a donation. http://www.python.org/psf/donations/ The Summary of Python Tracker Issues is an automatically generated report summarizing new bugs, closed ones, and patch submissions. http://search.gmane.org/?author=status%40bugs.python.org&group=gmane.comp.python.devel&sort=date Although unmaintained s
Re: [RELEASED] Python 3.1 final
On Mon, 29 Jun 2009 13:57:49 +0200, Hallvard B Furuseth wrote:
>> Okay, that's useful, except that it may have some bugs:
>> (...)
>> Assuming that this gets fixed, it should make most of the problems with
>> 3.0 solvable. OTOH, it wouldn't have killed them to have added e.g.
>> sys.argv_bytes and os.environ_bytes.
>
> That's hopeless to keep track of across modules if something modifies
> sys.argv or os.environ.
Oh, I wasn't suggesting that they should be updated. Just that there
should be some way to get at the original data.
The mechanism used in 3.1 is sufficient. I'm mostly concerned that it's
*possible* to recover the data; convenience is of secondary importance.
Calling sys.setfilesystemencoding('iso-8859-1') right at the start of the
code eliminates most of the issues. It's just the stuff which happens
before the first line of code is executed (sys.argv, os.environ, sys.stdin
etc) which was problematic.
[BTW, it isn't just Python that has problems. The directory where I was
performing tests happened to be an svn checkout. A subsequent "svn update"
promptly crapped out because I'd left behind a file whose name wasn't
valid ASCII.]
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Find the name of a setup tools plugin when its class is known.
Hi, Using pkg_resources, I can iterate through the plugins in an entrypoint and note down the plugin classes and all using "pkg_resources.iter_entry_points(ENTRYPOINT)" Now, when the plugin is loaded, I want to know it's entrypoint name as I have to load a bunch of settings identified by the name string. Regards, SZ " life isn't heavy enough,it flies away and floats far above action" Access Yahoo!7 Mail on your mobile. Anytime. Anywhere. Show me how: http://au.mobile.yahoo.com/mail -- http://mail.python.org/mailman/listinfo/python-list
Re: [RELEASED] Python 3.1 final
On Mon, 29 Jun 2009 11:41:11 +, Antoine Pitrou wrote:
> Nobody nowhere.com> writes:
>>
>> This results in an internal error:
>>
>> > "\udce4\udceb\udcef\udcf6\udcfc".encode("iso-8859-1", "surrogateescape")
>> Traceback (most recent call last):
>> File "", line 1, in
>> SystemError: Objects/bytesobject.c:3182: bad argument to internal function
>
> Please report a bug on http://bugs.python.org
Done.
> As for a bytes version of sys.argv and os.environ, you're welcome to propose a
> patch (this would be a separate issue on the aforementioned issue tracker).
Assuming that the above bug gets fixed, it isn't really necessary. In
particular, maintaining bytes/string versions in the presence of updates
is likely to be more trouble than it's worth.
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Re: pep 8 constants
alex23 wrote: > "Eric S. Johansson" wrote: >> no, I know the value if convention when editors can't tell you anything about >> the name in question. I would like to see more support for disabled >> programmers >> like myself and the thousands of programmers injured every year and forced to >> leave the field. seriously, there is no money in disability access >> especially >> for programmers. > > Well, if we can't use conventions like uppercasing, camelcasing and > underscoring, what are you recommending we do instead? help build a smart editing environment please. > > You seem to be asking us to change our behaviour to benefit only > others, but without offering any guidance on to how that is possible. > More importantly, shouldn't these modifications to common conventions > be coming _from_ the community of disabled programmers? I have a hard > time ensuring that I've gotten accurate requirements from co-workers > with whom I can actually see and speak, trying to determine how I > could write my code with accessibility in mind without any established > means of gauging success just seems impossible. Extremely valid point. The behavior I'm asking you to change is to consider the impact choices you make have on people with disabilities. I can only advocate for disabled programmer since I am one. Have been so for over 15 years. Have tried to maintain my position as architectural expert only to receive from venture capitalists and the likes "what good are you, you can't know enough to design our systems because you can't code" (yes, real quote). This is not always the case but enough that it really hurts my economics as well as the economics of other disabled programmers. Back in early 2000, I ran a series of workshops on the very issue of programming by voice. Back then we recognized the necessity for very smart editing environments which can tell us enough about what each symbol means so that we can direct the appropriate transformations from a higher-level grammar. I've introduce concepts such as command disambiguation through reduction of scope. Other people have added very good ideas with regards to usability and user interfaces for speech driven environment. Unfortunately, they all are gluons to an editor and they don't really integrate well because the editor isn't smart enough. Heck, have you ever noticed how most Python smart editors can't even indent properly according to local contexts. Emacs is the only one and even that one sometimes fails I can give you guidance as to what needs to be done. Other people can give guidance but I'm shooting for what may seem unachievable. Work with me a while and I will guide you as to how it's achievable. Maybe not by you but by someone we can find. I have lived way too many years with circus tricks. I don't want to end my life realizing I wasted my time in IT and regretting that I didn't take up the offer by mass rehab to go in restaurant or hotel management. one thing you can do to get a feel for out life is to get a copy of Naturally Speaking standard (100$ staples) and remove/cover keyboard. write email etc at first (10h) then try to write pep8 code. note to anyone who tries this, I'll support you in getting DNS running and help figure out any problems. only cost is if I tell you to do something like get a new mic, *do it*. I've lived this works and probably have put more deep thought and 8kloc into it because I do not accept circures tricks as a way of life. I want it to work right and I know how to do it. I just don't have the hands and hte money to pay me to do it. > >> and forgive me if this comes off sounding like a jerk but if >> the collective you don't give a sh** about your fellow programmers, who will? > > This isn't intended to be callous, as I feel that the collective > doesn't care as a whole about _any_ programmers, but isn't the answer > the very same disabled programmers for whom accessibility is an issue? > Programming tends to be needs driven (which, admittedly, can be simply > "to pay the bills"), and those who have a need tend to be better at > working out how to address it. yup how long will i be before you become disablesd? maybe not as badly as I am but you should start feeling some hand problems in your later 40's to early 50's and it goes down hill from there. self preservation/interest comes to mind as a possible motive for action. I thought 15 years would be enough for somebody else to push the isssue but no. if it is going to be, it has to be me. > > One possibility may be to approach a group for whom accessibility is > already a consideration, such as the Gnome Accessibility Project: > http://live.gnome.org/GAP not right focus for this project. tis one needs **deep** python knowledge (gvr level) and embedding it into an editor. heck, maybe we need a python interpreter in the editor to resolve some of the symbol stuff if we can get useful data from incomplete code. and I'll leave you an editor fea
Re: problems with mysql db
golu wrote:
here i have posted my code...plz tell why am i getting the error "int
argument required" on the hash marked line(see below) although i am
giving an int value
... url_count += 1
curse.execute("INSERT INTO URL_TABLE VALUES(%d,%s)",
(url_count,file_path)) #error
> ...
Try something more like:
> ... url_count += 1
> curse.execute("INSERT INTO URL_TABLE VALUES(%d,%s)",
> [(url_count,file_path)])
> ...
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Using Python for file packing
I'm working on a Python application right now that uses a large number of audio assets. Instead of having a directory full of audio, I'd like to pack all the audio into a single file. Is there any easy way to do this in Python? My first instinct was to attempt to pickle all the audio data, but something tells me that that experiment would only end in tears. -- http://mail.python.org/mailman/listinfo/python-list
Re: pep 8 constants
Tim Chase wrote: It sounds like the issue should be one of making your screen-reader > smarter, not dumbing down Python conventions. I don't know what SR > you're using (Jaws? Window Eyes? yasr? screeder? speakup? Naturally speaking is speech recognition (speech in text out) it is not text to speech although it does have a pluging for that -- http://mail.python.org/mailman/listinfo/python-list
Re: creating garbage collectable objects (caching objects)
Gabriel Genellina wrote: En Mon, 29 Jun 2009 08:01:20 -0300, Dave Angel escribió: News123 wrote: What I was more concerned is a group of output images depending on TWO or more input images. Depending on the platform (and the images) I might not be able to preload all two (or more images) So, as CPython's garbage collection takes always place immediately, then I'd like to pursue something else. I can create a cache, which caches input files as long as python leaves at least n MB available for the rest of the system. As I said earlier, I think weakref is probably what you need. A weakref is still a reference from the point of view of the ref-counting, but not from the point of view of the garbage collector. Have you read the help on weakref module? In particular, did you read Pep 0205? http://www.python.org/dev/peps/pep-0205/ You've misunderstood something. A weakref is NOT "a reference from the point of view of the ref-counting", it adds zero to the reference count. When the last "real" reference to some object is lost, the object is destroyed, even if there exist weak references to it. That's the whole point of a weak reference. The garbage collector isn't directly related. py> from sys import getrefcount as rc py> class X(object): pass ... py> x=X() py> rc(x) 2 py> y=x py> rc(x) 3 py> import weakref py> r=weakref.ref(x) py> r py> rc(x) 3 py> del y py> rc(x) 2 py> del x py> r (remember that getrefcount -as any function- holds a temporary reference to its argument, so the number it returns is one more than the expected value) Object cache is one of the two reasons for the weakref module. ...when you don't want the object to stay artificially alive just because it's referenced in the cache. But the OP wants a different behavior, it seems. A standard dictionary where images are removed when they're no more needed (or a memory restriction is fired). Thanks for correcting me. As I said earlier, I have no experience with weakref. The help and the PEP did sound to me like it would work for his needs. So how about adding an attribute in the large object that refers to the object iself?. Then the ref count will never go to zero, but it can be freed by the gc. Also store the ref in a WeakValueDictionary, and you can find the object without blocking its gc. And no, I haven't tried it, and wouldn't unless a machine had nothing important running on it. Clearly, the gc might not be able to keep up with this kind of abuse. But if gc is triggered by any attempt to make too-large an object, it might work. DaveA -- http://mail.python.org/mailman/listinfo/python-list
Creating an Instance Messenger type of application
Hello,Has anyone created an Instance Messenger in Python before, i mean a simple or Complex GUI based instance messenger? I thought about something like, the client also act as server, has it`s own listening port, but how can i handle uer auth? and adding visual effects to it. Please i am not trying to design another Yahoo IM/Skype but just for learning and also want to create real live application using the socket module. -- http://mail.python.org/mailman/listinfo/python-list
Re: [RELEASED] Python 3.1 final
On Mon, 29 Jun 2009 13:05:51 +0100, Paul Moore wrote:
>> As for a bytes version of sys.argv and os.environ, you're welcome to
>> propose a patch (this would be a separate issue on the aforementioned
>> issue tracker).
>
> But please be aware that such a proposal would have to consider:
>
> 1. That on Windows, the native form is the character version, and the
> bytes version would have to address all the same sorts of encoding
> issues that the OP is complaining about in the character versions. [1]
A bytes version doesn't make sense on Windows (at least, not on the
NT-based versions, and the DOS-based branch isn't worth bothering about,
IMHO).
Also, Windows *needs* to deal with characters due to the
fact that filenames, environment variables, etc are case-insensitive.
> 2. That the proposal address the question of how to write portable,
> robust, code (given that choosing argv vs argv_bytes based on
> sys.platform is unlikely to count as a good option...)
There is a tension here between robustness and portability. In my
situation, robustness means getting the "unadulterated" data. I can always
adulterate it myself if I need to.
> 3. Why defining your own argv_bytes as argv_bytes =
> [a.encode("iso-8859-1", "surrogateescape") for a in sys.argv] is
> insufficient (excluding issues with bugs, which will be fixed
> regardless) for the occasional cases where it's needed.
Other than the bug, it appears to be sufficient. I don't need to support
a locale where nl_langinfo(CODESET) is ISO-2022 (I *do* need to support
lossless round-trip of ISO-2022 filenames, possibly stored in argv and
maybe even in environ, but that's a different matter; the code only
really needs to run with LANG=C).
> [1] And my understanding, from the PEP, is that even on POSIX, the
> argv and environ data is intended to be character data, even though
> the native C APIs expose a byte-oriented interface. So conceptually,
> character format is "correct" on POSIX as well... (But I don't write
> code for POSIX systems, so I'll leave it to the POSIX users to debate
> this point further).
Even if it's "intended" to be character data, it isn't *required* to be.
In particular, it's not required to be in the locale's encoding.
A common example of what I need to handle is:
find /www ... -print0 | xargs -0 myscript
where the filenames can be in a wide variety of different encodings
(sometimes even within a single directory).
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Ctypes, pthreads and pthread_mutex_t
Has any converted the structure pthread_mutex_t to a ctypes structure class ? I looking at some C code that is using pthreads and need to translate pthreads_mutex_t structure into python (via ctypes) Thanks -- http://mail.python.org/mailman/listinfo/python-list
Making code run in both source tree and installation path
Hello, I would like to be able to run the main script in a python project from both the source tree and the path in which it's installed on Ubuntu. The script, among other things, imports a package which in turns makes use of some data files that contains some metadata that is needed in xml format. The source tree has an structure such as this one: setup.py debian/ (packaging files) src/ (source code) src/lib (package files) src/data (data files) src/bin (main script) However, when the project is installed using setup.py install, the directory structure is approximately this way: /usr/local/bin (main script) /usr/local/share/ (data files) /usr/local/lib/python2.x/dist-packages/ (library files) And when installing the code through a package, the structure is the same one, but removing "local". Hence, the data files aren't always in the same relative directories depending on we're executing code from the source tree or from the installation. To make it possible to run the code from both places, I've seen different approaches: - distutils trick in setup.py to modify the installed script (i.e. changing a global variable value) so that it has a reference to the data files location. - Heuristic in the package code to detect when it's being executed from the source tree and when it has been the installed - Just using an environment variable that the user must set according to his needs I guess that there are other options, for example, maybe using buildout. What would you say it's the best/more elegant option to solve this problem? Best regards, Javier -- http://mail.python.org/mailman/listinfo/python-list
Re: Using Python for file packing
On Mon, Jun 29, 2009 at 9:17 PM, Aaron Scott wrote: > I'm working on a Python application right now that uses a large number > of audio assets. Instead of having a directory full of audio, I'd like > to pack all the audio into a single file. Is there any easy way to do > this in Python? My first instinct was to attempt to pickle all the > audio data, but something tells me that that experiment would only end > in tears. Do you mean like a zip or tar file? http://docs.python.org/library/zipfile.html http://docs.python.org/library/tarfile.html -- kushal -- http://mail.python.org/mailman/listinfo/python-list
Re: Using Python for file packing
> Do you mean like a zip or tar file? > > http://docs.python.org/library/zipfile.htmlhttp://docs.python.org/library/tarfile.html > I had no idea you could access a single file from a ZIP or TAR without explicitly extracting it somewhere. Thanks. -- http://mail.python.org/mailman/listinfo/python-list
Re: Creating an Instance Messenger type of application
On Mon, Jun 29, 2009 at 12:18 PM, Elf Scripter wrote: > Hello, > Has anyone created an Instance Messenger in Python before, i mean a simple > or Complex GUI based instance messenger? > I thought about something like, the client also act as server, has it`s own > listening port, but how can i handle uer auth? and adding visual effects to > it. > Please i am not trying to design another Yahoo IM/Skype but just for > learning and also want to create real live application using the socket > module. Instant, not Instance, Did you check google? -- http://mail.python.org/mailman/listinfo/python-list
Re: pythonware.com down?
I'm having the same problem accessing pythonware or effbot. I can't find any news about their server status. I can ping both addresses just fine. Does anyone know what is going on? Maybe the ghosts of celebrities recently passed are mucking with the tubes. RIP Billy Mays -- http://mail.python.org/mailman/listinfo/python-list
Re: Creating an Instance Messenger type of application
On Mon, Jun 29, 2009 at 12:44 PM, Elf Scripter wrote: > Thank you for correcting my mistake. > I checked google but nothing close. did you have any idea? > > On Mon, Jun 29, 2009 at 5:42 PM, Simon Forman wrote: >> >> On Mon, Jun 29, 2009 at 12:18 PM, Elf Scripter >> wrote: >> > Hello, >> > Has anyone created an Instance Messenger in Python before, i mean a >> > simple >> > or Complex GUI based instance messenger? >> > I thought about something like, the client also act as server, has it`s >> > own >> > listening port, but how can i handle uer auth? and adding visual effects >> > to >> > it. >> > Please i am not trying to design another Yahoo IM/Skype but just for >> > learning and also want to create real live application using the socket >> > module. >> >> Instant, not Instance, Did you check google? > > I wouldn't try writing an IM or IRC client and/or server directly on the socket module, unless you really really wanted the learning experience. You might look at the "words" sub-project of the Twisted project [1] (although Twisted code has a significant learning curve itself, they do almost all of the network related heavy lifting for you.) There's also apparently a python binding to something called libpurple which seems to be a library used/provided by the "purple" multi-protocol IM/IRC client (used to be called GAIM). [2] HTH, ~Simon [1] http://twistedmatrix.com/trac/wiki/TwistedWords [2] http://briglia.net/wiki/tiki-index.php?page=Python-purple+Howto -- http://mail.python.org/mailman/listinfo/python-list
Re: fork, threads and proper closing
On 29 juin, 14:44, Francesco Bochicchio wrote: > On 29 Giu, 07:10, OdarR wrote: > > > > > On 28 juin, 23:26, Tomasz Pajor wrote: > > > > Hello, > > > > Configuration is as follows. > > > > I have a starter process which creates 3 sub processes (forks) and each > > > of this processes creates a number of threads. > > > Threads in that processes have semaphore so on KeyboardInterrupt without > > > sending a sigterm to the subprocess i'm not able to close threads. > > > Is there any work around? Can I somehow run join for the thread on > > > keyboard interrupt? > > > When creating a thread you can add a Queue parameter to communicate > > with threads:http://docs.python.org/library/queue.html > > easy and reliable. > > > give them a "poison pill" in the queue: a recognizable object placed > > on the queue that means "when you get this, stop." > > This is the way I usually go, but it has one important limitation: if > the thread is waiting > for a blocking I/O operation to complete, like reading from a socket > with no data or waiting add a small wait (time.sleep()), and also, I/O function in Python can often releas the GIL... > for a locked resource (i.e. semaphore) to be unlocked, it will not > service the queue and will > not read the 'quit command' (the poison pill), and therefore will not > quit until the blocking > I/O terminates (and it could be never). > > ASAIK, there is no way - in python - to solve this. no easy way, yes... but I think I gave a good advice to our friend Tomasz :) Olivier -- http://mail.python.org/mailman/listinfo/python-list
python library call equivalent to `which' command
Hi, I'm looking for a Python library function that provides the same functionality as the `which' command--namely, search the $PATH variable for a given string and see if it exists anywhere within. I currently examine the output from `which' itself, but I would like something more portable. I looked through the `os' and `os.path' modules but I didn't find anything. TIA Craig -- http://mail.python.org/mailman/listinfo/python-list
Re: pep 8 constants
Eric S. Johansson wrote: yup how long will i[t] be before you become disablesd? maybe not as badly as I am but you should start feeling some hand problems in your later 40's to early 50's and it goes down hill from there. self preservation/interest comes to mind as a possible motive for action. I thought 15 years would be enough for somebody else to push the isssue but no. if it is going to be, it has to be me. For anyone who is still able to use their hands for typing, especially if you're beginning to encounter the painful wrists, consider switching to a Dvorak layout. It was a system I was curious about even before I needed it, and when I did need it I was able to create the layout in assembler (now, of course, it's widely available as a standard keyboard layout). I started noticing the pain in my late twenties (aggravated, I'm sure, by arthritis), but with switching to Dvorak the pain left and has only very rarely been noticable again. It will mostly likely be a challenge to switch, but well worth it. http://en.wikipedia.org/wiki/Dvorak_Simplified_Keyboard ~Ethan~ -- http://mail.python.org/mailman/listinfo/python-list
Re: validating HTTPS certificates?
[email protected] wrote: > I'm in the process of picking a language for a client application that > accesses a HTTPS (actually SOAP) server. This would be easy enough in > Python, but I came across a strange fact: neither httplib nor urllib > offer the possibility to actually verify the server's certificate. Right, stdlib does not do this for you automatically. You'd either need to write that code yourself, or use a third party library. I wrote a long post about this when 2.6 came out: http://www.heikkitoivonen.net/blog/2008/10/14/ssl-in-python-26/ -- Heikki Toivonen -- http://mail.python.org/mailman/listinfo/python-list
Re: Python Imaging Library download link broken?
On Jun 29, 2:54 pm, peter wrote: > Whilst this is an interesting discussion about installers, I'm still > trying to find a copy of PIL. Any ideas? Hello, I had the very same problem and found this: http://www.portablepython.com/ It contains PIL and some other cool stuff. Hope it helps. George -- http://mail.python.org/mailman/listinfo/python-list
Re: python library call equivalent to `which' command
On Mon, Jun 29, 2009 at 12:54 PM, destroy wrote:
> Hi,
> I'm looking for a Python library function that provides the same
> functionality as the `which' command--namely, search the $PATH
> variable for a given string and see if it exists anywhere within. I
> currently examine the output from `which' itself, but I would like
> something more portable. I looked through the `os' and `os.path'
> modules but I didn't find anything.
This works on POSIX systems. Windows uses semicolons to separate paths
rather than colons so that would need to be taken into account when
running on Windows. This also doesn't recognize shell built-ins, only
real binaries.
import os
def which(file):
for path in os.environ["PATH"].split(":"):
if file in os.listdir(path):
print "%s/%s" % (path, file)
>>> which("ls")
/bin/ls
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Re: python library call equivalent to `which' command
Tim Pinkawa wrote:
On Mon, Jun 29, 2009 at 12:54 PM, destroy wrote:
Hi,
I'm looking for a Python library function that provides the same
functionality as the `which' command--namely, search the $PATH
variable for a given string and see if it exists anywhere within. I
currently examine the output from `which' itself, but I would like
something more portable. I looked through the `os' and `os.path'
modules but I didn't find anything.
This works on POSIX systems. Windows uses semicolons to separate paths
rather than colons so that would need to be taken into account when
running on Windows. This also doesn't recognize shell built-ins, only
real binaries.
import os
def which(file):
for path in os.environ["PATH"].split(":"):
if file in os.listdir(path):
print "%s/%s" % (path, file)
which("ls")
/bin/ls
There's a "which.py" in the tools directory included in
the Python distribution. On windows, that's
c:\python26\tools\scripts; don't know where to look
on Linux.
Don't know how good it is as I -- like many, I suspect --
wrote my own, which in my case is Windows-specific.
TJG
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TWiki Python API Wrapper
Has anyone come across a decent python API wrapper for TWiki? I'm trying to automate some reports and logs to automatically post, create topics, and re-arrange a few things on our TWiki, but my googleFu has failed me :( I did find an interesting module in Perl, http://cpanratings.perl.org/dist/WWW-Mechanize-TWiki . Looking at the TWiki documentations, I found a perl API reference: http://twiki.org/cgi-bin/view/TWiki/TWikiFuncDotPm . A proof of concept, using these two perl modules, was generated by a blog post here: http://roberthanson.blogspot.com/2006/01/copying-from-blogger-to-twiki-with.html Before I make my own pythonic port, using mechanize, and wrapping around the aforementioned TWiki api, I wanted to see if anyone had any other ideas, approaches, or modules to help expedite the task? Thanks! Mahmoud Abdelkader -- http://mail.python.org/mailman/listinfo/python-list
Re: No trees in the stdlib?
Paul Rubin wrote: The idea is you can accomplish the equivalent of insertion or deletion by allocating a new root, along with the path down to the place you want to insert, i.e. O(log n) operations. So instead of mutating an existing tree, you create a new tree that shares most of its structure with the old tree, and switch over to using the new tree. Now I get what your have been talking about over several posts. Update and mutate are kind of synonymous in my mind, but the above explains how they can be different. This trivially lets you maintain snapshots of old versions of the tree, implement an "undo" operation, have a background thread do a complex operation on a snapshot while the foreground thread does any number of update-and-replace operations, etc. This is very standard stuff. Now for someone raised on arrays, iteration, and procedural programming ;-). http://en.wikipedia.org/wiki/Persistent_data_structure Reading it now. The wikipedia article on AVL trees makes it pretty obvious how an implementation would work. -- http://mail.python.org/mailman/listinfo/python-list
Re: pep 8 constants
Ethan Furman wrote: > Eric S. Johansson wrote: >> >> yup how long will i[t] be before you become disablesd? maybe not as >> badly as I am >> but you should start feeling some hand problems in your later 40's to >> early 50's >> and it goes down hill from there. self preservation/interest comes to >> mind as a >> possible motive for action. I thought 15 years would be enough for >> somebody >> else to push the isssue but no. if it is going to be, it has to be me. > > For anyone who is still able to use their hands for typing, especially > if you're beginning to encounter the painful wrists, consider switching > to a Dvorak layout. It was a system I was curious about even before I > needed it, and when I did need it I was able to create the layout in > assembler (now, of course, it's widely available as a standard keyboard > layout). I started noticing the pain in my late twenties (aggravated, > I'm sure, by arthritis), but with switching to Dvorak the pain left and > has only very rarely been noticable again. It will mostly likely be a > challenge to switch, but well worth it. a good suggestion but not really addressing the point I'm trying to make of building a system that would help people more profoundly injured. for example, I've tried Dvorak and the act of typing was so painful that I couldn't learn it -- http://mail.python.org/mailman/listinfo/python-list
Direct interaction with subprocess - the curse of blocking I/O
Hello everyone I've had real issues with subprocesses recently : from a python script, on windows, I wanted to "give control" to a command line utility, i.e forward user in put to it and display its output on console. It seems simple, but I ran into walls : - subprocess.communicate() only deals with a forecast input, not step-by-step user interaction - pexpect module is unix-only, and for automation, not interactive input - when wanting to do all the job manually (transfering data between the standard streams of the python program and the binary subprocess, I met the issue : select() works only on windows, and python's I/O are blocking, so I can't just, for example, get data from the subprocess' stdout and expect the function to return if no input is present - the requesting thread might instead block forever. Browsing the web, I found some hints : - use the advanced win32 api to create non-blocking I/O : rather complicated, non portable and far from the python normal files - use threads that block on the different streams and eat/feed them without ever stopping : rather portable, but gives problems on shutdown (How to terminate these threads without danger ? On some OSes, a process never dies as long as any thread - even "daemonic" - lives, I've seen people complaining about it). So well, I'd like to know, do you people know any solution to this simple problem - making a user interact directly with a subprocess ? Or would this really require a library handling each case separately (win32 api, select().) ? Thanks a lot for your interest and advice, regards, Pascal -- http://mail.python.org/mailman/listinfo/python-list
Re: python library call equivalent to `which' command
Tim Pinkawa wrote:
> def which(file):
> for path in os.environ["PATH"].split(":"):
> if file in os.listdir(path):
> print "%s/%s" % (path, file)
"if file in os.list()" is slow and not correct. You have to check if the
file is either a real file or a symlink to a file and not a directory or
special. Then you have to verify that the file has the executable bit, too.
Christian
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Re: Q: finding distance between 2 time's
In <[email protected]> Steven D'Aprano writes: > > if time_difference < 3601: > That's a potential off-by-one error. [...] The right test is: > if time_difference <= 3600: Aren't those two comparisons the same? -- John Gordon A is for Amy, who fell down the stairs [email protected] B is for Basil, assaulted by bears -- Edward Gorey, "The Gashlycrumb Tinies" -- http://mail.python.org/mailman/listinfo/python-list
Re: pep 8 constants
Rhodri James wrote:
> On Mon, 29 Jun 2009 06:07:19 +0100, Eric S. Johansson
> wrote:
>
>> Rhodri James wrote:
>>
>>> Reject away, but I'm afraid you've still got some work to do to
>>> convince me that PEP 8 is more work for an SR system than any other
>>> convention.
>>
>
> [snip sundry examples]
>
> Yes, yes, recognition systems need both training and a careful selection
> of words to recognise to be effective. This I learned twenty years ago:
> if "cap" has a high failure rate, use something else.
A more profitable way would be to build a framework doing the right job and not
trying to make it happen by side effect and "speaking the keyboard". Speaking
the keyboard is whenever you force someone to go through gyrations to adjust
spacing, case or special single character assertions (i.e.;).
>
> As far as I can tell, the only thing that you are even vaguely suggesting
> for convention use is underscores_with_everything. As promised, I laugh
> hollowly.
I'm sorry. It may have been too subtle. I'm suggesting a smart editor that can
tell me anything about any name in the body of code I'm working or anything I've
included. with that kind of tool, I can have a command grammar that is much
friendlier to the voice and gets work done faster than typing.things such as:
what is this name?
it's a class.
What are its methods?
tree
branch
root
root template plea
se
.root(howmany=1, branches=3, nodes={})
and the query can go from there.
Using tools like these, one can keep pep-8 conventions and not create a
discriminatory environment.
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Re: python library call equivalent to `which' command
On Mon, Jun 29, 2009 at 2:17 PM, Christian Heimes wrote: > "if file in os.list()" is slow and not correct. You have to check if the > file is either a real file or a symlink to a file and not a directory or > special. Then you have to verify that the file has the executable bit, too. I realize four lines of Python does not replicate the functionality of which exactly. It was intended to give the original poster something to start with. I am curious about it being slow, though. Is there a faster way to get the contents of a directory than os.listdir() or is there a faster way to see if an element is in a list other than "x in y"? I believe 'which' will terminate once it finds any match, which mine does not, but that can be fixed by adding a break after the print. -- http://mail.python.org/mailman/listinfo/python-list
Re: python library call equivalent to `which' command
On Mon, Jun 29, 2009 at 2:31 PM, Tim Pinkawa wrote: > I am curious about it being slow, though. Is there a faster way to get > the contents of a directory than os.listdir() or is there a faster way > to see if an element is in a list other than "x in y"? I believe > 'which' will terminate once it finds any match, which mine does not, > but that can be fixed by adding a break after the print. To answer my own question on this specific case, you could check with os.access which may be faster. I am still curious, Christian, if your issue with it being slow was that "os.listdir is slow" or "os.listdir is slow in this case". -- http://mail.python.org/mailman/listinfo/python-list
Re: python library call equivalent to `which' command
On Mon, 29 Jun 2009 13:53:30 -0500, Tim Pinkawa wrote:
>> I'm looking for a Python library function that provides the same
>> functionality as the `which' command--namely, search the $PATH
>> variable for a given string and see if it exists anywhere within. I
>> currently examine the output from `which' itself, but I would like
>> something more portable. I looked through the `os' and `os.path'
>> modules but I didn't find anything.
>
> This works on POSIX systems. Windows uses semicolons to separate paths
> rather than colons so that would need to be taken into account when
> running on Windows. This also doesn't recognize shell built-ins, only
> real binaries.
FWIW, "which" doesn't recognise built-ins either; the "type" built-in
does.
> import os
>
> def which(file):
> for path in os.environ["PATH"].split(":"):
> if file in os.listdir(path):
> print "%s/%s" % (path, file)
There are a couple of problems with this:
1. "which" only considers executable files, and the default behaviour is
to only display the first matching file. Also, I'm assuming that the OP
wants a function which returns the path rather than printing it.
2. os.listdir() requires read permission (enumerate permission) on each
directory. The standard "which" utility stat()s each possible candidate,
so it only requires execute permission (lookup permission) on the
directories. A secondary issue is performance; enumerating a directory to
check for a specific entry can be much slower than stat()ing the specific
entry. IOW:
def which(file):
for path in os.environ["PATH"].split(os.pathsep):
if os.access(os.path.join(path, file), os.X_OK):
return "%s/%s" % (path, file)
But for Windows, you also need to use PATHEXT, e.g.:
for dir in os.environ["PATH"].split(os.pathsep):
for ext in os.environ["PATHEXT"].split(os.pathsep):
full = os.path.join(dir, "%s.%s" % (file, ext))
if os.access(full, os.X_OK):
return full
Disclaimer: I don't know how accurate os.access(..., os.X_OK) is on
Windows; OTOH, it's probably as good as you'll get.
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Re: python library call equivalent to `which' command
On 2009-06-29 14:31, Tim Pinkawa wrote: On Mon, Jun 29, 2009 at 2:17 PM, Christian Heimes wrote: "if file in os.list()" is slow and not correct. You have to check if the file is either a real file or a symlink to a file and not a directory or special. Then you have to verify that the file has the executable bit, too. I realize four lines of Python does not replicate the functionality of which exactly. It was intended to give the original poster something to start with. I am curious about it being slow, though. Is there a faster way to get the contents of a directory than os.listdir() or is there a faster way to see if an element is in a list other than "x in y"? I believe 'which' will terminate once it finds any match, which mine does not, but that can be fixed by adding a break after the print. Just check if os.path.exists(os.path.join(path, filename)). -- Robert Kern "I have come to believe that the whole world is an enigma, a harmless enigma that is made terrible by our own mad attempt to interpret it as though it had an underlying truth." -- Umberto Eco -- http://mail.python.org/mailman/listinfo/python-list
Re: python library call equivalent to `which' command
Tim Pinkawa wrote: > I realize four lines of Python does not replicate the functionality of > which exactly. It was intended to give the original poster something > to start with. Agreed! > I am curious about it being slow, though. Is there a faster way to get > the contents of a directory than os.listdir() or is there a faster way > to see if an element is in a list other than "x in y"? I believe > 'which' will terminate once it finds any match, which mine does not, > but that can be fixed by adding a break after the print. You don't need to get the entire directory content to see if a file exists. The stat() syscall is much faster because it requires fewer disk reads. On modern file systems stat() is a O(1) operation while "file" in listdir() is a O(n) operation. By the way you need the result of os.stat anyway to see if the file has the executable bits set. Christian -- http://mail.python.org/mailman/listinfo/python-list
Re: Tutorials on Jinja
On Thu, 25 Jun 2009 07:17:42 -0700 (PDT), Saurabh wrote: >On Jun 25, 2:04 am, Wayne Brehaut wrote: >> On Wed, 24 Jun 2009 11:46:55 -0700 (PDT), Saurabh >> >> wrote: >> >Hi All, >> >> >I am trying to move my application on a MVC architecture and plan to >> >use Jinja for the same. Can anyone provide me with few quick links >> >that might help me to get started with Jinja? >> >> Perhaps the most useful link is: >> >> http://www.google.com/ >> >> from which you can easily find many more with a very basic search, >> including: >> >> http://jinja.pocoo.org/ >> >> Hope that helps? >> wwwayne >> >> >> >> >Thanks, >> >Saby >> >> > >Thanks (Sir!). I was hoping to get some good tutorial on >implementation (which I wasn't able to find with a basic search - >http://dev.pocoo.org/projects/lodgeit/ is what I was referring to >earlier) as this is my first assignment on any template engine (never >used Cheetah, MakO, Tempita). >I would appreciate people responding with something helpful. If you >find a question pretty naive, kindly ignore the question rather than >passing comments on it. Doesn't helps anyone's time. Not phrasing questions in a helpful way initially also doesn't lead to good use of anyone's time, and I suggest another link: http://catb.org/esr/faqs/smart-questions.html Your original question asked for a "few quick links that might help me to get started with Jinja", which made it appear you didn't know where to start and hadn't yet done even a basic search yourself, so I thought I *was* being helpful. Now that you provide the information that would have helped others to respond more usefully previously, perhaps they will. w >Thanks again -- http://mail.python.org/mailman/listinfo/python-list
Re: Q: finding distance between 2 time's
On Mon, 29 Jun 2009 19:15:08 +, John Gordon wrote: >> > if time_difference < 3601: > >> That's a potential off-by-one error. [...] The right test is: > >> if time_difference <= 3600: > > Aren't those two comparisons the same? Not if time_difference is a float. -- http://mail.python.org/mailman/listinfo/python-list
Re: Q: finding distance between 2 time's
John Gordon wrote: In <[email protected]> Steven D'Aprano writes: if time_difference < 3601: That's a potential off-by-one error. [...] The right test is: if time_difference <= 3600: Aren't those two comparisons the same? Only if time_difference is an integer. --Scott David Daniels [email protected] -- http://mail.python.org/mailman/listinfo/python-list
Re: python library call equivalent to `which' command
On Mon, 29 Jun 2009 14:31:25 -0500, Tim Pinkawa wrote: >> "if file in os.list()" is slow and not correct. You have to check if the >> file is either a real file or a symlink to a file and not a directory or >> special. Then you have to verify that the file has the executable bit, too. > > I realize four lines of Python does not replicate the functionality of > which exactly. It was intended to give the original poster something > to start with. > > I am curious about it being slow, though. Is there a faster way to get > the contents of a directory than os.listdir() No. > or is there a faster way to see if an element is in a list other than > "x in y"? No. However, there is a faster (and more correct) way to test for file existence than enumerating the directory then checking whether the file is in the resulting list, namely to stat() the file. I.e. os.path.exists() or os.access(); the latter will allow you to check for execute permission at the same time. On some systems, the speed difference may be very significant. If readdir() is a system call, os.listdir() will make one system call (two context switches) per directory entry, while os.access() will make one system call in total. [Linux has the (non-standard) getdents() system call, which returns multiple directory entries per call. The readdir() library function uses getdents(), as it is much more efficient than using the readdir() system call.] -- http://mail.python.org/mailman/listinfo/python-list
Re: Advantages of Python (for web/desktop apps)?
iceangel89 wrote: > i am mainly a PHP (mainly using Zend Framework MVC now) Web Developer. used > .NET (VB & C#) for Desktop apps. i nv used Python and am looking at Python > now (for desktop apps since its open source and just want to try what it > offers, but will like to know what good it has for web development also) Give it a try. wxPython or PyQt is preferred for GUI development in general on win32. PyGTK also works on win32 but maybe isn't as nice-looking as the first two options (although the API is much more pythonic by some accounts). The Idle IDE may get you started. When you've profiled your program and found where the common cases are slow, then you can work on optimization substitution pure python routines with native ones written in C, C++, etc -- http://mail.python.org/mailman/listinfo/python-list
Re: python library call equivalent to `which' command
On Mon, 29 Jun 2009 21:53:42 +0200, Christian Heimes wrote: >> I am curious about it being slow, though. Is there a faster way to get >> the contents of a directory than os.listdir() or is there a faster way >> to see if an element is in a list other than "x in y"? I believe >> 'which' will terminate once it finds any match, which mine does not, >> but that can be fixed by adding a break after the print. > > You don't need to get the entire directory content to see if a file > exists. The stat() syscall is much faster because it requires fewer disk > reads. On modern file systems stat() is a O(1) operation while "file" in > listdir() is a O(n) operation. Apart from performance, stat() is more correct. readdir() (and Linux' getdents()) requires read permission on the directory, while stat() (and open() etc) only requires execute permission. On shared web (etc) servers, it's not uncommon for system directories (e.g. /usr/bin) to be "drwxr-x--x", as normal users shouldn't need to enumerate these directories. -- http://mail.python.org/mailman/listinfo/python-list
Re: What does Guido want in a GUI toolkit for Python?
Martin v. Löwis wrote: I sorta' wish he'd just come out and say, "This is what I think would be suitable for a GUI toolkit for Python: ...". He is not in the business of designing GUI toolkits, but in the business of designing programming languages. So he abstains from specifying (or even recommending) a GUI library. What he makes clear is the point that Terry cites: no matter what the GUI toolkit is or what features it has - it should be simple to create GUIs, as simple as creating HTML. Having quoted Guido, I will note a few other things: Python already comes with a GUI toolkit, so the question is really "What would Guido want in a replacement for tk/tkinter?" Obviously, it should be even better that the current (and even, prospective) version of TK. 'Better' would need to be demonstrated. Part of that would be a PEP written by or supported by the person in charge of the replacement, with a detailed comparison and argument. Part of that would also be a re-writing of IDLE with the new GUI, with some visible advantage in the gui part of the code. I do not believe either has been done. The replacement should also have majority support. However, there are at least 3 or 4 contenders. My impression is that most of the supporters of each prefer (and rationally so) the status quo to having one of the other contenders being chosen, and thereby shutting out their favorite. The replacement would need to work with Py 3. TK does. I have not noticed that anything else does, though that should change eventually. (And I am sure someone will point of something I have not noticed.) Guido is properly somewhat conservative about 'spending' BDFL points. There is no need to decide anything at present. Terry Jan Reedy -- http://mail.python.org/mailman/listinfo/python-list
Re: Direct interaction with subprocess - the curse of blocking I/O
On Mon, 29 Jun 2009 21:15:52 +0200, Pascal Chambon wrote: > I've had real issues with subprocesses recently : from a python script, > on windows, I wanted to "give control" to a command line utility, i.e > forward user in put to it and display its output on console. Are you talking about a popen(..., 'w') situation? I.e. where Python feeds data to the child's stdin but the child's stdout doesn't go through Python? Or a slave process, where both stdin and stdout/stderr are piped to/from Python? The latter is inherently tricky (which is why C's popen() lets you connect to stdin or stdout but not both). You have to use either multiple threads, select/poll, or non-blocking I/O. If the child's output is to the console, it should presumably be the former, i.e. piping stdin but allowing the child to inherit stdout, in which case, where's the problem? Or are you piping its stdout via Python for the hell of it? -- http://mail.python.org/mailman/listinfo/python-list
Re: Python Imaging Library download link broken?
Thanks for this - looks promising. But I've just tried pythonware again and it's back up - so it was just a glitch after all. Peter -- http://mail.python.org/mailman/listinfo/python-list
Re: alternative to JoinableQueue's please
ps: Thanks Raymond for the quick reply... and I feel rather apologetic for having bothered the list with this :S No need to feel that way -- many of us still learn from simple looking problems! :) ~Ethan~ -- http://mail.python.org/mailman/listinfo/python-list
Re: Using Python for file packing
Aaron Scott wrote: Do you mean like a zip or tar file? http://docs.python.org/library/zipfile.htmlhttp://docs.python.org/library/tarfile.html I had no idea you could access a single file from a ZIP or TAR without explicitly extracting it somewhere. Thanks. You will find the zip format works better if you are compressing. The zipfile compression is per file in the archive, rather than applied to the entire archive (as in tarfile). The results of the tar format decision is that extracting the last file in a .tgz (.tar.gz) or .tar.bz2 (sometimes called .tbz) requires the expansion of the entire archive, while extraction on a .zip is reposition, read, and possibly expand. --Scott David Daniels [email protected] -- http://mail.python.org/mailman/listinfo/python-list
