date:20090813


naaman wrote:

On Aug 12, 1:35 pm, Dave Angel  wrote:
  

naaman wrote:


I'm writing my first Python script and
I want to use fileinput to open a file in r+ mode.
Tried fileinput.input(sys.argv[1:],"r+") but that didn't work.
ANy ideas?
  
Need to find and overwrite a line in a file several times.

I can do it using open and seek() etc. but was wondering if I can use
fileinput.
  
thanks;
  

I haven't used it, but check out the 'inplace' keyword parameter.

DaveA



I've only Python for a week so I'm not sure what inplace does

  

You should read the docs for it
   ( http://www.python.org/doc/2.6.2/library/fileinput.html  ),
but it's not very clear to me either  So I dug up an example on the web:
(ref:   http://effbot.org/librarybook/fileinput.htm )

import fileinput, sys

for line in fileinput.input(inplace=1):
   # /convert Windows/DOS text files to Unix files/
   if line[-2:] == "\r\n":
   line = line[:-2] + "\n"
   sys.stdout.write(line)


The inplace argument tells it to create a new file with the same name as 
the original (doing all the necessary nonsense with using a scratch 
file, and renaming/deleting) for each file processed.  Stdout is pointed 
to that new version of the file.  Notice that you have to explicitly 
write everything you want to wind up in the file -- if a given line is 
to remain unchanged, you just write "line" directly.


If you're new to Python, I do not recommend trying to do open/seek to 
update a text file in place, especially if you're in DOS.  There are 
lots of traps.  the inplace method of fileinput avoids these by 
implicitly creating temp files and handling the details for you, which 
probably works great if you're dealing with text, in order.


DaveA

--
http://mail.python.org/mailman/listinfo/python-list

Re: csv.DictWriter.write_header()

2009-08-13 Thread John Machin

On Aug 13, 1:15 pm, Alan G Isaac  wrote:
> > On Aug 13, 6:45 am, Alan G Isaac  wrote:
> >> Given a csv.DictWriter instance `dw`
> >> I think it would be nice to be able to
> >> say dw.write_header()
> >> instead of
> >> dw.writer.writerow(dw.fieldnames)
>
> >> Good idea?
>
> On 8/12/2009 10:24 PM John Machin apparently wrote:
>
> > Yes, it's a brilliant idea. All you have to do is insert the following
> > lines in your code after importing csv:
>
> > csv.DictWriter.write_header = (
> >     lambda dw: dw.writer.writerow(dw.fieldnames)
> >     )
>
> I do not understand the reason for your silly, sarcastic response.

Duck typing: ask a silly question, get a silly answer.

> I already showed you how to achieve the result,

What result? You said (in effect) "I think it would be nice to be able
to write A instead of B". You didn't show any way of setting things up
so that one could write A instead of B.

I showed one way. Other possibilities are a 2-line patch to the users
own csv.py, and submitting a patch to the dev team. The second is
kludgy, and there could be a wait until e.g. 2.7 before the third
happens. So back to the first way; everybody should have a utility
module that they import to do little fixes like that ... here is a
slightly more robust version:

import csv
try:
csv.DictWriter.write_header
except AttributeError:
csv.DictWriter.write_header = (
lambda dw: dw.writer.writerow(dw.fieldnames)
)

> so obviously
> I am not just asking for my own personal gain.

???

> I take it you do not realize that many users do not see
> a simple way to get this often needed functionality.

No, I don't. How did you come to that realisation? AFAICT they don't
ask in this forum or on StackOverflow.

> (For example, see the gymnatics suggested by Shai Vaingast
> in his otherwise excellent and useful book.)

I can imagine that one might (without reading the source) make do with
the published APIs:

dw = csv.DictWriter(open(...), my_field_names
dw.writerow(dict((fn, fn) for fn in my_field_names))

> And indeed,
> there is no reason to expect them to.

Indeed not, as for somebody who otherwise sees utility in the
DictWriter class not having a writer_headers method is a glaring
deficiency.

Note that there is a difference between "expecting C to do X" and
"expecting C to be able to do X". I really hope you don't mean that
people should not be encouraged to be able to write a trivial class
like csv.DictWriter and add trivial functionality themselves ... or to
be able to just write the required functionality inline:

wtr = csv.writer(open(...), ...)
wtr.writerow(my_field_names)
for adict in source_of_dicts():
wtr.writerow(adict[fn] for fn in my_field_names)

or even:

for obj in source_of_objects():
wtr.writerow(getattr(obj, fn) for fn in my_field_names)

> So my question was, would this improve the class from
> a usability perspective?

Of course.

>  Do you have a useful response?

See above. Also, the csv module appears to be in two minds about
underscores in attribute names (field_size_limit, skipinitialspace,
writerow, writerows) -- it may cause less confusion if it were called
writeheader (consistent with writerow).
-- 
http://mail.python.org/mailman/listinfo/python-list

Re: best practice for documenting a project? pydoc?


Hello Jean-Michel,

Thanks for your post. Based on it, and the ones received so
far I will give epydoc a closer look. I don't need something
superfancy (at least at the moment), just something that helps
me document my code more in an organized way and helps me
sift through the various classes/methods more easily once I
come back to the project after some lengthy interruptions.

Best,

Esmail

Jean-Michel Pichavant wrote:



I've never used Happydoc. I am using Epydoc, which is very efficient. 
Sphinx is very good as well, but its scope is much larger than 
documenting python code and will not provide  the "click and run"  
effect of epydoc,  for which you don't have to write any additional 
documentation. Epydoc supports restructured text, so you'll be able to 
switch to Sphinx later on without additional work.
But if I remember well, your documentation is for personal use, so I 
guess you'll stick with epydoc.


--
http://mail.python.org/mailman/listinfo/python-list

Re: httplib incredibly slow :-(

2009-08-13 Thread David Robinow

On Thu, Aug 13, 2009 at 3:20 AM, Chris Withers wrote:
> David Robinow wrote:
>>
>> On Wed, Aug 12, 2009 at 12:37 PM, Chris Withers
>> wrote:
>>>
>>> David Stanek wrote:

 Also on the same box where you run this script
 can you test with curl or wget?
>>>
>>> It's a Windows box, so no :-(
>>
>> Why not?
>>
>> http://users.ugent.be/~bpuype/wget/
>> http://curl.haxx.se/download.html
>
> Fair point, but I don't see what this will achieve...
>
> I've already established that the file downloads in seconds with [something
> else], so I'd like to understand why python isn't doing the same and fix the
> problem...
 My post was simply to correct the implication that curl and wget can
not be used on Windows. It's up to you whether you want to use one or
the other.
 I'm not the OP, and this is not my area of expertise, but ...
  You've got two data points. You've jumped to the conclusion that
there's something wrong with Python or your code. You're probably
right. However, if you try wget, for example, and it's as slow as your
code, you cqn look elsewhere.  If, on the other hand, wget is as fast
as IE, you'll have more proof that your code is the problem.
 Then, since wget is open source you can look at the source code and
see what wget is doing right that you (or httplib) is doing wrong.
-- 
http://mail.python.org/mailman/listinfo/python-list

PIL and Python

2009-08-13 Thread [email protected]

Hello !
I want use python to change the "note" from .jpeg files .
What is the functions on PIL how make this ?
Thank you !
-- 
http://mail.python.org/mailman/listinfo/python-list

Re: How to launch a function at regular time intervals ?

2009-08-13 Thread Grant Edwards

On 2009-08-13, Dave Angel  wrote:

> I'm assuming you want to call it every time_interval seconds, on 
> average, with a little jitter allowed on each call, but keeping correct 
> long term.  In other words, if one call is a little late, you want the 
> next one to still happen as close to on-time as possible.
>
> The general outline is something like (untested):
>
> times_called = 0   #number of times function has been called
> start_time = now
> while True:
>  elapsed = now - start_time
>  int_elapsed = int(elapsed/time_interval)
>  for times_called in range(times_called, int_elapsed):
> call_the_function()
>  sleep(time_interval/10)   #this might give us 10% jitter, which 
> is usually fine

I don't understand the reasoning behind the above loop --
specifically the sleeping of smaller intervals than needed.

Why not something like this:

interval = 5.0  # interval in seconds
next = time.time()

while True:
now = time.time()
if now < next:  
time.sleep(now-next)
print "call_the_function()"
next += interval

That will be accurate over the long term with minimal jitter.

  

-- 
http://mail.python.org/mailman/listinfo/python-list

Re: what is it, that I don't understand about python and lazy evaluation?

2009-08-13 Thread Antoine Pitrou

Erik Bernoth  googlemail.com> writes:
> 
> Isn't it strange, that this code runs (in a lazy language) for eternity?

Python is a not a lazy language.
`and` and `or` are particular, they are language constructs (*), not operators,
that's why they can decide whether or not to evaluate their second term. It's a
feature, but this feature is not general to Python.

(*) by this I mean they have similar status as, for example, `if` and `else`

-- 
http://mail.python.org/mailman/listinfo/python-list

Re: Networked Broadcast Messaging

2009-08-13 Thread Greg Taylor

On Aug 11, 9:18 pm, David Bolen  wrote:
>
> If you want better guarantees, you might look into a distributed
> message bus like Spread (http://www.spread.org/) or perhaps a
> messaging protocol like XMPP (http://xmpp.org/) through its PubSub
> extension.  Both have Python interfaces, though I have no personal
> experience with either.  But perhaps that will also give you some
> terms or starting points for searching for other options.

This is also very helpful. In particular Spread, looks very
attractive.

Thanks for the tip,

Greg
-- 
http://mail.python.org/mailman/listinfo/python-list

Re: Social problems of Python doc [was Re: Python docs disappointing]

2009-08-13 Thread rurpy

On 08/12/2009 12:27 PM, Raymond Hettinger wrote:
> On Aug 12, 3:32 am, Paul Boddie  wrote:
>> Maybe the problem is that although everyone welcomes contributions and
>> changes (or says that they do), the mechanisms remain largely beyond
>> criticism.
>
> FWIW, I support the idea the regular docs incorporating links to
> freely editable wiki pages.  That will at least make it easier for
> people to make changes or add notes.
>
> That being said, I would like to add a few thoughts about the
> current process.   ISTM that important corrections (when the
> docs are clearly in error) tend to get made right away.  What
> is more interesting are the doc requests that get rejected
> and why:

[...snip interesting categorization of "bad" doc enhancement
suggestions...]

> In short, most doc requests that get rejected are requests that didn't
> actually improve the documentation.
>
> I do support links from the regular docs to an external wiki but the
> main docs should continue to go through the regular process using the
> tracker.

What is the purpose of such a wiki?

1. To provide hopefully useful adjunct information for each
doc page?

2. To provide a source of input for improving the next version
of the docs?

In general I have a low opinion of wikis.  Nearly all the ones
I've seen are trash heaps of out-dated and wrong information,
atrocious writing, and comments that look like the middle of
some arcane usenet thread.  They lack organization making it
very difficult to find the needles of good information in the
haystack of junk.  The only one that seems to work is Wikipedia
and it "works" because it has a very heavy-weight process
controlling contributions.  (And even then, my biggest complaint
with Wikipedia is the poor writing quality in a lot of articles.)

I'm not trying to be negative, only pointing out that to serve
either of the goals I asked about above, a wiki will probably
require a considerable management effort that should be faced
up front.  To simply set up a wiki and "wait for it to
self-organize" (as I here read once) is a pipe-dream.

How will it be managed?  Anything written stays?  If not what
standards are used to remove junk entries?  Wrong entries?
Questionable entries?  Who will do this?  Will they act based
on their own judgment or some documented formal standards?
What happens to comments when a new doc version is released?
What happens when entries become obsolete?  What happens when
comments are disputed?

If the goal is (2) what kind of wiki contributions are being
solicited ("I don't understand what this sentence means"? a
complete rewrite of a section?) and how is that communicated?
Who will take a long string of wiki comments constituting a
discussion and condense them into something that can be
submitted as a doc patch?  (This I suspect is where the
work is, where someone with good writing skills is needed.)
Will this process be sufficient to raise the quality of the
docs significantly, or are other steps also needed such as
an attitude shift in what the core committers consider
acceptable?

If the goal is (1) above, it could potentially have a
deleterious effect on the docs in that it will be easier to
respond to requests to expand some description with, "there's
no need since that is covered in (or belongs in) the wiki
comments".

All the above not withstanding, I too think a wiki is worth
trying.  But without doing a lot more than just "setting up
a wiki", I sadly believe even a python.org supported wiki
is doomed to failure.
-- 
http://mail.python.org/mailman/listinfo/python-list

IFL 2009: Final Call for Papers and Participation

2009-08-13 Thread IFL 2009

Call for Papers and ParticipationIFL 2009Seton Hall UniversitySouth Orange, NJ, USAhttp://tltc.shu.edu/blogs/projects/IFL2009/Register at: http://tltc.shu.edu/blogs/projects/IFL2009/registration.html* NEW *Registration and talk submission deadline fast approaching: August 23, 2009***The 21st International Symposium on Implementation and Application of Functional Languages, IFL 2009, will be held for the first time in the USA. The hosting institution is Seton Hall University in South Orange, NJ, USA and the symposium dates are September 23-25, 2009. It is our goal to make IFL a regular event held in the USA and in Europe. The goal of the IFL symposia is to bring together researchers actively engaged in the implementation and application of functional and function-based programming languages. IFL 2009 will be a venue for researchers to present and discuss new ideas and concepts, work in progress, and publication-ripe results related to the implementation and application of functional languages and function-based programming.Following the IFL tradition, IFL 2009 will use a post-symposium review process to produce a formal proceedings which will be published by Springer in the Lecture Notes in Computer Science series. All participants in IFL 2009 are invited to submit either a draft paper or an extended abstract describing work to be presented at the symposium. These submissions will be screened by the program committee chair to make sure they are within the scope of IFL and will appear in the draft proceedings distributed at the symposium. Submissions appearing in the draft proceedings are not peer-reviewed publications. After the symposium, authors will be given the opportunity to incorporate the feedback from discussions at the symposium and will be invited to submit a revised full arcticle for the formal review process. These revised submissions will be reviewed by the program committee using prevailing academic standards to select the best articles that will appear in the formal proceedings.Invited Speaker:    Benjamin C. Pierce    University of Pennsylvania    Talk Title: How To Build Your Own Bidirectional Programming LanguageTOPICSIFL welcomes submissions describing practical and theoretical work as well as submissions describing applications and tools. If you are not sure if your work is appropriate for IFL 2009, please contact the PC chair at [email protected]. Topics of interest include, but are not limited to: language concepts  type checking  contracts compilation techniques  staged compilation runtime function specialization runtime code generation  partial evaluation   (abstract) interpretation  generic programming techniques  automatic program generation  array processing  concurrent/parallel programming  concurrent/parallel program execution  functional programming and embedded systems  functional programming and web applications  functional programming and security  novel memory management techniques  runtime profiling and performance measurements  debugging and tracing  virtual/abstract machine architectures  validation and verification of functional programs    tools and programming techniques  FP in EducationPAPER SUBMISSIONSProspective authors are encouraged to submit papers or extended abstracts to be published in the draft proceedings and to present them at the symposium. All contributions must be written in English, conform to the Springer-Verlag LNCS series format and not exceed 16 pages. The draft proceedings will appear as a technical report of the Department of Mathematics and Computer Science of Seton Hall University.IMPORTANT DATESRegistration deadline   August 23, 2009Presentation submission deadline    August 23, 2009IFL 2009 Symposium  September 23-25, 2009Submission for review process deadline  November 1, 2009Notification Accept/Reject  December 22, 2009Camera ready version    February 1, 2010PROGRAM COMMITTEEPeter Achten  University of Nijmegen, The NetherlandsJost Berthold Philipps-Universität Marburg, GermanyAndrew Butterfield    University of Dublin, IrelandRobby Findler Northwestern University, USAKathleen Fisher   AT&T Research, USACormac Flanagan   University of California at Santa Cruz, USAMatthew Flatt University of Utah, USAMatthew Fluet Toyota Technological Institute at Chicago, USADaniel Friedman   Indiana University, USAAndy Gill University of Kansas, USAClemens Grelck    University of Amsterdam/Hertfordshire, The Netherlands/UKJurriaan Hage Utrecht University, The NetherlandsRalf Hinze    Oxford University, UKPaul Hudak    Yale University, USAJohn Hughes   Chalmers University of Technology, SwedenPatricia Johann   University of Strathclyde, UKYukiyoshi Kameyama    University of Tsukuba, JapanMarco T. Morazán

Re: Social problems of Python doc [was Re: Python docs disappointing]

2009-08-13 Thread Paul Boddie

On 13 Aug, 16:05, [email protected] wrote:
>
> All the above not withstanding, I too think a wiki is worth
> trying.  But without doing a lot more than just "setting up
> a wiki", I sadly believe even a python.org supported wiki
> is doomed to failure.

The ones on python.org seem to function reasonably well. I accept that
they could be more aggressively edited, but this isn't done because
there's a compromise between letting people contribute and keeping
things moderately coherent, with the former being favoured. For other
purposes, it would be quite acceptable to favour editorial control.

I won't argue that providing infrastructure solves a problem - that's
precisely the kind of thing I was criticising when I noted that some
people will readily criticise the choice of tools to do a job instead
of focusing on the job that has to be done - and you need people who
are reasonably competent editors, but Wiki solutions remove a lot of
technical barriers. I'm not arguing for the flavour of Wiki which
implies unfettered, anonymous access from everyone on the Internet,
either: the kind of Wiki that detractors portray all Wiki solutions as
being in order to further their super-special "it has to fit like a
glove or it's totally unusable" software agenda. It's quite possible
to have people with somewhat more privileges than others in order to
keep the peace, and they don't all need to have an entrenched
editorial interest: on the current python.org Wiki sites, most of the
administrators don't have an active interest in most of the content,
but they are able to exercise control when it's clear that some
contributors aren't particularly interested in actually improving the
content.

As well as having an active community effort around the existing
python.org Wiki sites, there are also people who are interested in
improving these offerings. What worries me is that despite such
activity and such interest, many people will continue to lament the
lack of vitality (or whatever other metric) of the general python.org
offering, whilst retaining a blind spot for the obvious contribution
that the Wikis can make to such improvement efforts. I encourage
people to use wiki.python.org a lot more, should they be looking to
improve the wealth of information provided by the community.

Paul
-- 
http://mail.python.org/mailman/listinfo/python-list

Re: Re: what is it, that I don't understand about python and lazy evaluation?




Antoine Pitrou wrote:

Erik Bernoth  googlemail.com> writes:
  

Isn't it strange, that this code runs (in a lazy language) for eternity?



Python is a not a lazy language.
`and` and `or` are particular, they are language constructs (*), not operators,
that's why they can decide whether or not to evaluate their second term. It's a
feature, but this feature is not general to Python.

(*) by this I mean they have similar status as, for example, `if` and `else`



  

Agreed.

In fact, I don't know of any aspect of Python which I'd call lazy, 
although the word appears in the docs in a few places.  I've seen, but 
not used, languages which had lazy evaluations.  Simplest example would 
be an infinite precision math package, where the actual precision is not 
actually used till something external to the program got visibility to 
the value.  So the constant PI might really be a generator, which would 
generate enough precision for whatever the value was being used for.  If 
you did a free-form print of PI, the console would never terminate (in 
principle), but in practice, it'd get slower and slower printing out the 
digits till the machine ran out of memory, or the user lost patience.


Python, on the other hand has at least three short-circuit operations, 
in which parts of the expression are defined not to be evaluated at all, 
if other parts meet certain conditions.  These are the 'and' and 'or' 
keywords mentioned above, the chained comparison construct, and the 
conditional expression, added recently.  In each of these, the semantics 
of the language require that those parts not be evaluated.

   val =  (42 < x < function())
   val =  19 if i<12 else function()
   val =  x  or  function()

In each example, the function() may or may not be actually called, 
depending on the other values of the expression.


DaveA

--
http://mail.python.org/mailman/listinfo/python-list

Tkinter Menu in Frame

2009-08-13 Thread Sparky

Hello! I am trying to figure out if it is possible to place a Tkinter
menu within a frame. This would be instead of having the menu-bar at
the top of the window.

Thanks,
Sam
-- 
http://mail.python.org/mailman/listinfo/python-list

Re: loops for ffmpeg CLI in python

2009-08-13 Thread Albert Hopkins

On Wed, 2009-08-12 at 11:29 +0200, fakhar Gillani wrote:
>  
> Hi,
>  
> I am a begineer in Python. Actually I am encoding video files with
> different bitrates using ffmpeg CLI. I wanted to ask you that how can
> I make loops so that I can vary the bitrates in the CLI of ffmpeg??
>  
> I want to bulid a loop for the command below where i just want to vary
> the -vb parameter i.e. 10M. 
>  
> ffmpeg.exe -i sample.avi -y -f h264 -vb 10M -r 25
> encoded_1000_0-05.h264
>  
> I have tried to make simple loops but it doest work:(
>  
> Can anyone here help me out?

It might help if you specify what you tried and why it didn't work (for
you).

-a


-- 
http://mail.python.org/mailman/listinfo/python-list

Re: Python configuration question when python scripts are executed using Appweb as web server.

2009-08-13 Thread Mark Lawrence


Gabriel Genellina wrote:
[snip]

Here are couple of links that discusses setting PYTHONPATH environment
variable.
http://docs.python.org/using/windows.html


Ouch, that document should be reworked and updated!
I don't understand this comment, given that the PEP370 Implementation 
section 2nd paragraph quite specifically refers to the use of 
PYTHONPATH, I quote. "The user site directory is added before the system 
site directories but after Python's search paths and PYTHONPATH. This 
setup allows the user to install a different version of a package than 
the system administrator but it prevents the user from accidently 
overwriting a stdlib module. Stdlib modules can still be overwritten 
with PYTHONPATH."  What am I missing?



http://www.daimi.au.dk/~chili/PBI/pythonpath.html



[snip]

--
Kindest regards.

Mark Lawrence.

--
http://mail.python.org/mailman/listinfo/python-list

Delegate attribute requests to object

2009-08-13 Thread Evan Kroske

I'm trying to use the decorator pattern in a program I'm developing. I want
to create a decorator object that works like the object it's decorating
except for a few functions. However, I'd rather not hard-code all the
identical functionality from the decorated object into the decorator object.
Is there a way I can intercept all the attribute and function requests for
the decorator and delegate them to the decorated object? Here's some example
code:

class Decorator:
>   def __init__():
>self.decorated = Decorated()
>
>  def newFunction():
># Do something
>pass
>
>  def interceptRequests(request):
>return self.decorated.request()
>
> class Decorated:
>  def __init__():
>self.variable = 10
>
>  def oldFunction():
># Do something
>pass


I want to be able to do something like this:

objectA = Decorator()
> objectB = Decorated()
> assert objectA.oldFunction() == objectB.oldFunction() # No error
>

Is it possible (without inheritance)?

--
Evan Kroske
http://welcome2obscurity.blogspot.com/
The code, comments, and challenges of a novice
software developer desperate for attention.
-- 
http://mail.python.org/mailman/listinfo/python-list

Re: Re: How to launch a function at regular time intervals ?


Grant Edwards wrote:

On 2009-08-13, Dave Angel  wrote:

  
I'm assuming you want to call it every time_interval seconds, on 
average, with a little jitter allowed on each call, but keeping correct 
long term.  In other words, if one call is a little late, you want the 
next one to still happen as close to on-time as possible.


The general outline is something like (untested):

times_called = 0   #number of times function has been called
start_time = now
while True:
 elapsed = now - start_time
 int_elapsed = int(elapsed/time_interval)
 for times_called in range(times_called, int_elapsed):
call_the_function()
 sleep(time_interval/10)   #this might give us 10% jitter, which is 
usually fine



I don't understand the reasoning behind the above loop --
specifically the sleeping of smaller intervals than needed.

Why not something like this:

interval = 5.0  # interval in seconds
next = time.time()

while True:
now = time.time()
if now < next:  
time.sleep(now-next)

print "call_the_function()"
next += interval

That will be accurate over the long term with minimal jitter.

  

  

Two reasons I didn't take an approach like that one.

1) I frequently need to do something else while waiting, so I tend to do 
multiple smaller sleeps.  As long as each sleep is at least 100ms, the 
overhead cost is pretty small.
2) If (occasionally) the function takes longer than the specified 
interval time, my approach does catch-up calls so the average remains 
the same.


My loop was only a rough outline, and if neither of these considerations 
applies, yours is much nicer.


DaveA
--
http://mail.python.org/mailman/listinfo/python-list

Interface to Exchange Calendar via web services

2009-08-13 Thread John Gordon

I have a python app that needs to look up a person's Exchage Calendar
entries to see if they are currently available.

Does anyone have any code examples for communicating with EWS (Exchange
Web Services)?  I've found some code in Java and CSharp to do this, but
none in python so far.

Thanks!

-- 
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: Delegate attribute requests to object

Perhaps I'm misunderstanding something, but I don't think that's really  
typical decorator behavior? Typically decorators, as I understand them,  
take an instance argument -- so you wouldn't be saying


def __init__(self):
self.decorated = Decorated()

you'd be saying

def __init__(self, decorated):
self.decorated = decorated

As for the attribute access, I believe you can override __getattr__ to do  
what you want:



class Decorator:
[snip]
def __getattr__(self, request):
return self.decorated.__getattr__(request)


The same thing should work for methods, although you may want to pass  
arguments through as well.


Is there a reason why, for this use, just making Decorator a subclass of  
Decorated (and only overriding the methods you need to be different)  
wouldn't work?


On Thu, 13 Aug 2009 08:50:47 -0700, Evan Kroske  wrote:

I'm trying to use the decorator pattern in a program I'm developing. I  
want

to create a decorator object that works like the object it's decorating
except for a few functions. However, I'd rather not hard-code all the
identical functionality from the decorated object into the decorator  
object.
Is there a way I can intercept all the attribute and function requests  
for
the decorator and delegate them to the decorated object? Here's some  
example

code:

class Decorator:

  def __init__():
   self.decorated = Decorated()

 def newFunction():
   # Do something
   pass

 def interceptRequests(request):
   return self.decorated.request()

class Decorated:
 def __init__():
   self.variable = 10

 def oldFunction():
   # Do something
   pass



I want to be able to do something like this:

objectA = Decorator()

objectB = Decorated()
assert objectA.oldFunction() == objectB.oldFunction() # No error



Is it possible (without inheritance)?

--
Evan Kroske
http://welcome2obscurity.blogspot.com/
The code, comments, and challenges of a novice
software developer desperate for attention.




--
Rami Chowdhury
"Never attribute to malice that which can be attributed to stupidity" --  
Hanlon's Razor

408-597-7068 (US) / 07875-841-046 (UK) / 0189-245544 (BD)
--
http://mail.python.org/mailman/listinfo/python-list

Re: How to launch a function at regular time intervals ?

2009-08-13 Thread David

Thanks all for your answers. As suggested by Dave and Frank, I am
indeed looking for the main program to continue running in the
background (I have several functions I want to launch, each at a
predefined time interval). I like Frank's solution, on the paper it
seems it would do what I am looking for, but I cannot succeed in
having it working. I guess I've been stuck with this problem for too
long and can't succeed in using my brain accurately anymore... ;-)

I defined the class as defined by Frank, and I then inserted the
following code in a While True loop, without any other code (the idea
is just to test Frank's solution before really using it in my
program):

func = MyFunction()
func.start()

func.stop()
func.join()

However I'm not getting the expected behavior. It's not taking into
account the 30 sec wait, the function is called again and again
without any time interval... Any idea ?

Again, thanks a lot.

-- 
http://mail.python.org/mailman/listinfo/python-list

Re: Social problems of Python doc [was Re: Python docs disappointing]

2009-08-13 Thread Steven D'Aprano

On Wed, 12 Aug 2009 20:23:27 -0700, rurpy wrote:

>> That's no different from *any* major refactoring. The exact same
>> problem exists for code as well as documentation. It's a solved problem
>> for code, and it's a solved problem for documentation.
> 
> Huh?  I don't buy this at all.  Code refactoring doesn't change the
> semantics of the program at all -- it simplifies the code that
> implements behavior without changing behavior.  How does this apply to
> revising documentation?  

My apologies, I mis-wrote. Of course refactoring is inappropriate in this 
context. What I meant was a major redesign where the API may change.

Except of course that documentation changes don't need to be concerned 
with backwards compatibility, except possibly to avoid breaking old links.

[...]
>> Yes it would. Most patches are ignored, because the dev team are
>> overworked, and if they don't see the need for a patch, they won't
>> approve it.
> 
> I'm confused.  If they weren't overworked, then they would approve
> patches they didn't see a need for?  

No.

If they're overworked, they're less likely to spend time investigating 
patches which aren't immediately obvious that they're needed.

And additionally, if the patch doesn't appear to be useful, it's unlikely 
to be approved. Why would it be?

> Or are you saying because they are
> overworked they fail to approve patches that should be approved?

Invariably there will be good patches missed because they haven't been 
noticed.

> I am
> not sure how either supports the argument that the tracker is the best
> method of improving the docs.

These are not arguments in favour of the tracker, these are realistic 
issues that any project of non-trivial size have to deal with. Virtually 
every project (not just software projects either) have to deal with the 
fact that there will be more things to do than resources to do them with.

[...]
>> No, submitting a tracker issue is a necessary but not sufficient step.
>> Without a tracker issue, you're very unlikely to have people agree to
>> replace the existing docs with your docs, although a PEP would probably
>> do it. (A PEP is significantly more effort than raising a tracker
>> issue.)
> 
> Has there ever been a PEP for a doc change?  Are you making a serious
> suggestion?

I don't know if there ever has been, but as far as I know, there are two 
ways to get changes approved to Python: informal approval by somebody 
with check-in privileges, or formal approval on the basis of a PEP. If 
you can't get the first, then the second is an option, albeit unlikely.

>>> As long as every "the docs
>>> sux" complaint is met here with the standard responses that I've
>>> mentioned,
>>
>> But they aren't met with such a so-called "standard response".
> 
> I just looked through the first 70 or so messages in this thread and in
> this case I have agree with you, most of the responses were not what I
> called "standard responses".  There was one guy, a Steven D'Aprano early
> on that trotted out the, "it's free software, fix it if you don't like
> it" line, 

And I stand by it. If you're not helping to solve the problem, then what 
exactly are you doing?

Even if you can't provide a patch, provide a bug report. What 
specifically is wrong with the docs? Be specific. Give examples. Explain 
why it is wrong. State your assumptions, e.g. what audience do you 
represent?

If you do these things, you're helping. If you're just complaining, then 
you're not.

>> We know that there are problems. We've said repeatedly that corrections
>> and patches are welcome. We've repeatedly told you how to communicate
>> your answer to the question of what should be done. None of this is
>> good enough for you. I don't know what else you expect.
> 
> You have been told repeatedly why your insistence that the tracker must
> be the only channel, is wrong.  I don't understand why you can't
> understand that.
> 
> (Generally only those in authority, bosses, parents, police, and the
> like, "tell" others what a situation is and have a right to demand that
> the subject accept it without question. I think you could find a more
> respectful and less authoritarian way of phrasing what you said above
> since you are not in a position of authority over me.)

"You're not my real dad!!!"

In the words of Jesse "The Body" Venture, I'm just telling it like it is. 
The tracker is the only practical way of getting doc changes accepted, 
for those without check-in privileges or the ear of someone with them. Me 
telling you this is no more an expression of authority than me telling 
you that the USA has 50 states.

Of course I could be wrong. My understanding of the facts might be wrong, 
or I may not be in full possession of all the relevant facts. If so, I 
welcome correction.

So please tell me, what other practical ways are there for an 
unprivileged person to get the official Python docs modified?

-- 
Steven
-- 
http://mail.python.org/mailman/listinfo/python-lis

Re: How to launch a function at regular time intervals ?

2009-08-13 Thread Grant Edwards

On 2009-08-13, Dave Angel  wrote:
> Grant Edwards wrote:
>> On 2009-08-13, Dave Angel  wrote:

>>> The general outline is something like (untested):
>>>
>>> times_called = 0   #number of times function has been called
>>> start_time = now
>>> while True:
>>>  elapsed = now - start_time
>>>  int_elapsed = int(elapsed/time_interval)
>>>  for times_called in range(times_called, int_elapsed):
>>> call_the_function()
>>>  sleep(time_interval/10)   #this might give us 10% jitter, 
>>> which is usually fine
>>
>> I don't understand the reasoning behind the above loop --
>> specifically the sleeping of smaller intervals than needed.
>>
>> Why not something like this:
>>
>> interval = 5.0  # interval in seconds
>> next = time.time()
>>
>> while True:
>> now = time.time()
>> if now < next:  
>> time.sleep(now-next)
>> print "call_the_function()"
>> next += interval
>>
>> That will be accurate over the long term with minimal jitter.
>>   
> Two reasons I didn't take an approach like that one.
>
> 1) I frequently need to do something else while waiting, so I
>tend to do multiple smaller sleeps.  As long as each sleep
>is at least 100ms, the overhead cost is pretty small.

I guess I always use a separate thread for cases like that.

> 2) If (occasionally) the function takes longer than the
>specified interval time, my approach does catch-up calls so
>the average remains the same.

I'm still confused -- doesn't mine do that as well?

-- 
Grant Edwards   grante Yow! Are you the
  at   self-frying president?
   visi.com
-- 
http://mail.python.org/mailman/listinfo/python-list

Re: Database query execution times in Python?

2009-08-13 Thread Aahz

In article ,
pwnedd   wrote:
>
>I've been writing some code using libraries based on the Python Database API
>2.0 (MySQLdb & pg), and so far things are working really well. There is one
>thing that I have not been able to figure out how to do, however: 
>
>Retrieve the time is took a given query to execute.

Look up EXPLAIN
-- 
Aahz ([email protected])   <*> http://www.pythoncraft.com/

"...string iteration isn't about treating strings as sequences of strings, 
it's about treating strings as sequences of characters.  The fact that
characters are also strings is the reason we have problems, but characters 
are strings for other good reasons."  --Aahz
-- 
http://mail.python.org/mailman/listinfo/python-list

Re: httplib incredibly slow :-(

2009-08-13 Thread Aahz

In article ,
Chris Withers   wrote:
>Aahz wrote:
>> In article ,
>> Chris Withers   wrote:
>>>
>>> Does anyone know of an alternative library for creating http requests 
>>> and getting their responses that's faster but hopefully has a similar 
>>> interface?
>> 
>> PyCurl
>
>This seems to be a wrapper around libcurl.
>Does it work on Windows?

Yes.

>If so, where can I find some decent examples?
>(the ones listed on the pycurl website are not what I'd call decent :-S)

Sorry, I mostly have been working on our Mac port, so I'm not sure what's
needed to make this work on Windows.  Did you try downloading the PyCurl
binary?  Maybe it statically links libcurl on Windows.

What do you need to know for a decent example?
-- 
Aahz ([email protected])   <*> http://www.pythoncraft.com/

"...string iteration isn't about treating strings as sequences of strings, 
it's about treating strings as sequences of characters.  The fact that
characters are also strings is the reason we have problems, but characters 
are strings for other good reasons."  --Aahz
-- 
http://mail.python.org/mailman/listinfo/python-list

Re: Social problems of Python doc [was Re: Python docs disappointing]

2009-08-13 Thread RJ

A basic question in this thread is: Who will host the 
doc-wiki/whatever and how will it be linked to?
If not hosted at python.org it can still be linked to from their 
docs, if allowed, possibly with 3rd level domain and re-direct.
I host a number of commercial servers but I don't expect Guido to 
bless them with said links.

If hosted at python.org it will require resources from the existing admins.
If elsewhere then trusted admins and organization.
If not linked to from python.org then it may well expire from lack of 
interest, as other seemingly nice attempts did.


Ray Schumacher



--
http://mail.python.org/mailman/listinfo/python-list

Re: How to launch a function at regular time intervals ?

2009-08-13 Thread MRAB


David wrote:

Thanks all for your answers. As suggested by Dave and Frank, I am
indeed looking for the main program to continue running in the
background (I have several functions I want to launch, each at a
predefined time interval). I like Frank's solution, on the paper it
seems it would do what I am looking for, but I cannot succeed in
having it working. I guess I've been stuck with this problem for too
long and can't succeed in using my brain accurately anymore... ;-)

I defined the class as defined by Frank, and I then inserted the
following code in a While True loop, without any other code (the idea
is just to test Frank's solution before really using it in my
program):

func = MyFunction()
func.start()

func.stop()
func.join()

However I'm not getting the expected behavior. It's not taking into
account the 30 sec wait, the function is called again and again
without any time interval... Any idea ?

Again, thanks a lot.


What exactly do you mean by "I then inserted the following code in a
While True loop"? Do you mean you put all four lines in it? If yes,
then you're repeatedly starting then stopping the function.
--
http://mail.python.org/mailman/listinfo/python-list

Re: Delegate attribute requests to object

More information at  
http://www.python.org/doc/2.5.2/ref/attribute-access.html if you need it  
:-)


On Thu, 13 Aug 2009 10:13:47 -0700, Evan Kroske  wrote:

I don't want to inherit from the classes I'm decorating because they  
have a
common superclass. I can make a generic decorator that I can use on all  
its

sibling classes. I'll try your getattr method to see if it works.

On Thu, Aug 13, 2009 at 12:07 PM, Rami Chowdhury
wrote:


Perhaps I'm misunderstanding something, but I don't think that's really
typical decorator behavior? Typically decorators, as I understand them,  
take

an instance argument -- so you wouldn't be saying

   def __init__(self):
   self.decorated = Decorated()

you'd be saying

   def __init__(self, decorated):
   self.decorated = decorated

As for the attribute access, I believe you can override __getattr__ to  
do

what you want:

 class Decorator:

[snip]
def __getattr__(self, request):
   return self.decorated.__getattr__(request)



The same thing should work for methods, although you may want to pass
arguments through as well.

Is there a reason why, for this use, just making Decorator a subclass of
Decorated (and only overriding the methods you need to be different)
wouldn't work?


On Thu, 13 Aug 2009 08:50:47 -0700, Evan Kroske 
wrote:

 I'm trying to use the decorator pattern in a program I'm developing. I

want
to create a decorator object that works like the object it's decorating
except for a few functions. However, I'd rather not hard-code all the
identical functionality from the decorated object into the decorator
object.
Is there a way I can intercept all the attribute and function requests  
for

the decorator and delegate them to the decorated object? Here's some
example
code:

class Decorator:


 def __init__():
  self.decorated = Decorated()

 def newFunction():
  # Do something
  pass

 def interceptRequests(request):
  return self.decorated.request()

class Decorated:
 def __init__():
  self.variable = 10

 def oldFunction():
  # Do something
  pass




I want to be able to do something like this:

objectA = Decorator()


objectB = Decorated()
assert objectA.oldFunction() == objectB.oldFunction() # No error



Is it possible (without inheritance)?

--
Evan Kroske
http://welcome2obscurity.blogspot.com/
The code, comments, and challenges of a novice
software developer desperate for attention.





--
Rami Chowdhury
"Never attribute to malice that which can be attributed to stupidity" --
Hanlon's Razor
408-597-7068 (US) / 07875-841-046 (UK) / 0189-245544 (BD)









--
Rami Chowdhury
"Never attribute to malice that which can be attributed to stupidity" --  
Hanlon's Razor

408-597-7068 (US) / 07875-841-046 (UK) / 0189-245544 (BD)
--
http://mail.python.org/mailman/listinfo/python-list

Re: what is it, that I don't understand about python and lazy evaluation?

2009-08-13 Thread Ethan Furman

Erik Bernoth wrote:

Hi List,

look at the following code:

def evens():
# iterator returning even numbers
i = 0
while True:
yield i
i += 2

# now get all the even numbers up to 15
L = [n for n in evens() if n < 15]

Isn't it strange, that this code runs (in a lazy language) for eternity? 
I would expect python to to spit out (in no time):

 >> L
[0, 2, 4, 6, 8, 10, 12, 14]

after 14 it is not nessesary to evaluate evens() any further.

I really started to ask myself if python really is lazy, but everything 
else I wrote in lazy style still worked. Example:

 >> def test(txt, retval):
..print(txt)
..return retval
..
 >>> test(1, True) or test(2, True)
1
True
 >>> test(1, True) and test(2, True)
1
2
True

Can anybody explain what happens with evens()?

best regards
Erik Bernoth

PS: The code comes from a list post from 2006. You find it here: 
http://mail.python.org/pipermail/python-list/2006-November/585783.html

As MRAB pointed out, the issue is not with evens, it's with the list 
comprehension.  The list comprehension doesn't know when to stop, only 
which numbers to include.

~Ethan~
--
http://mail.python.org/mailman/listinfo/python-list

Help newbie with how to call a source command

2009-08-13 Thread Joni Lee

Hi all,
 
I'm landing here because I need some help that I couldn't get through it.
Question 1. 
I want to call a source command from python script. It will source 
some variables enviroment for further commands. I tried the following which did 
not work
os.sys('source '+source_text)
call(['source',source_text], shell=True)
commands.getoutput('source '+source_text)
 
Anyone have experiences with this? Because I'm very new to this world so a 
details reply is really appreciated!!! thank you very much
 
Question 2.
I call a shell command from python, this time it runs a script which runs some 
ruby scripts. And the error returns: "ruby: command not found"
 
Thank you again


  -- 
http://mail.python.org/mailman/listinfo/python-list

Re: what is it, that I don't understand about python and lazy evaluation?

2009-08-13 Thread Ethan Furman

Ethan Furman wrote:

Erik Bernoth wrote:

Hi List,

look at the following code:

def evens():
# iterator returning even numbers
i = 0
while True:
yield i
i += 2

# now get all the even numbers up to 15
L = [n for n in evens() if n < 15]

Isn't it strange, that this code runs (in a lazy language) for 
eternity? I would expect python to to spit out (in no time):

 >> L
[0, 2, 4, 6, 8, 10, 12, 14]

after 14 it is not nessesary to evaluate evens() any further.

I really started to ask myself if python really is lazy, but 
everything else I wrote in lazy style still worked. Example:

 >> def test(txt, retval):
..print(txt)
..return retval
..
 >>> test(1, True) or test(2, True)
1
True
 >>> test(1, True) and test(2, True)
1
2
True

Can anybody explain what happens with evens()?

best regards
Erik Bernoth

PS: The code comes from a list post from 2006. You find it here: 
http://mail.python.org/pipermail/python-list/2006-November/585783.html

As MRAB pointed out, the issue is not with evens, it's with the list 
comprehension.  The list comprehension doesn't know when to stop, only 
which numbers to include.

~Ethan~

Actually, I am mistaken (gasp! shock! ;).  A list comprehension will run 
until the iterator(s) it's based on end, and even() runs forever.

~Ethan~
--
http://mail.python.org/mailman/listinfo/python-list

Re: How to address a global variable in a function

2009-08-13 Thread Aahz

In article <82c2f2e7-ed3e-482b-9318-d5539a2a9...@y10g2000prg.googlegroups.com>,
n179911   wrote:
>
>I have a global variable
>
>// line 8
>tx  = 0
>
>and then I have this function (start in line 12):
>def handleTranslate(result):
>   print line
>   txStr, tyStr = result.group(1), result.group(2)
>   print txStr, tyStr
>
>   tx += int(txStr)
>   ty += int(tyStr)
>
>   return

BTW, you probably want to learn why global names are a bad idea, I don't
have time to explain that here (or point you at references).  Going
through some of the online tutorials should address this.
-- 
Aahz ([email protected])   <*> http://www.pythoncraft.com/

"...string iteration isn't about treating strings as sequences of strings, 
it's about treating strings as sequences of characters.  The fact that
characters are also strings is the reason we have problems, but characters 
are strings for other good reasons."  --Aahz
-- 
http://mail.python.org/mailman/listinfo/python-list

Re: Delegate attribute requests to object

Oops, my apologies, it's the __getattribute__ method you want to call on  
self.decorated (because __getattr__ won't be there unless you define it  
specifically)


So it should go:

def __getattr__(self, request):
return self.decorated.__getattribute__(request)



On Thu, 13 Aug 2009 11:00:28 -0700, Evan Kroske  wrote:


Unfortunately, __getattr__ didn't work. When I try to use your code

class Decorator:

[snip]
def __getattr__(self, request):
   return self.decorated.__getattr__(request)



I get this error:

AttributeError: 'Decorated' object has no attribute '__getattr__'




Is that a private method, or am I simply using it wrong? Thanks for the
help.

On Thu, Aug 13, 2009 at 1:18 PM, Rami Chowdhury  
wrote:



More information at
http://www.python.org/doc/2.5.2/ref/attribute-access.html if you need it
:-)


On Thu, 13 Aug 2009 10:13:47 -0700, Evan Kroske 
wrote:

 I don't want to inherit from the classes I'm decorating because they  
have

a
common superclass. I can make a generic decorator that I can use on all
its
sibling classes. I'll try your getattr method to see if it works.

On Thu, Aug 13, 2009 at 12:07 PM, Rami Chowdhury
wrote:

 Perhaps I'm misunderstanding something, but I don't think that's  
really
typical decorator behavior? Typically decorators, as I understand  
them,

take
an instance argument -- so you wouldn't be saying

  def __init__(self):
  self.decorated = Decorated()

you'd be saying

  def __init__(self, decorated):
  self.decorated = decorated

As for the attribute access, I believe you can override __getattr__  
to do

what you want:

 class Decorator:


[snip]
def __getattr__(self, request):
  return self.decorated.__getattr__(request)



The same thing should work for methods, although you may want to pass
arguments through as well.

Is there a reason why, for this use, just making Decorator a subclass  
of

Decorated (and only overriding the methods you need to be different)
wouldn't work?


On Thu, 13 Aug 2009 08:50:47 -0700, Evan Kroske 
wrote:

 I'm trying to use the decorator pattern in a program I'm developing.  
I



want
to create a decorator object that works like the object it's  
decorating

except for a few functions. However, I'd rather not hard-code all the
identical functionality from the decorated object into the decorator
object.
Is there a way I can intercept all the attribute and function  
requests

for
the decorator and delegate them to the decorated object? Here's some
example
code:

class Decorator:

  def __init__():

 self.decorated = Decorated()

 def newFunction():
 # Do something
 pass

 def interceptRequests(request):
 return self.decorated.request()

class Decorated:
 def __init__():
 self.variable = 10

 def oldFunction():
 # Do something
 pass




I want to be able to do something like this:

objectA = Decorator()

 objectB = Decorated()

assert objectA.oldFunction() == objectB.oldFunction() # No error


 Is it possible (without inheritance)?


--
Evan Kroske
http://welcome2obscurity.blogspot.com/
The code, comments, and challenges of a novice
software developer desperate for attention.





--
Rami Chowdhury
"Never attribute to malice that which can be attributed to stupidity"  
--

Hanlon's Razor
408-597-7068 (US) / 07875-841-046 (UK) / 0189-245544 (BD)









--
Rami Chowdhury
"Never attribute to malice that which can be attributed to stupidity" --
Hanlon's Razor
408-597-7068 (US) / 07875-841-046 (UK) / 0189-245544 (BD)









--
Rami Chowdhury
"Never attribute to malice that which can be attributed to stupidity" --  
Hanlon's Razor

408-597-7068 (US) / 07875-841-046 (UK) / 0189-245544 (BD)
--
http://mail.python.org/mailman/listinfo/python-list

i Don't get why it makes trouble

>>> j
[u'Tata', u'Oriovac', u'PrimorskoGoranska', u'hrvatska', u'Kuna']
>>> len(j)
5
>>> h = """SELECT distinct u.id_ulica, o.id_opcina, z.id_zupanija, d.id_drzava, 
>>> v.id_valuta FROM   ulica as u, opcina as o, zupanija as z, drzava as d, 
>>> valuta as v  WHERE  u.naziv = '%s' AND o.naziv = '%s' AND z.naziv = '%s' 
>>> AND d.naziv = '%s' AND v.naziv = '%s'""" % (j)
Traceback (most recent call last):
  File "", line 1, in 
TypeError: not enough arguments for format string


I want to format the string. the list has five elements and the string
has five placeholder but it wont format the string
-- 
http://mail.python.org/mailman/listinfo/python-list

[ANN] pyjamas 0.6pre3 released

2009-08-13 Thread Luke Kenneth Casson Leighton

much as we'd very much like to declare a 0.6 stable release, really
really soon and move forward, the ChangeLog just keeps growing (133
and counting) with the bugfixes, testing and contributions since
0.5p1.

pyjamas is a port of GWT to python, and includes a
python-to-javascript compiler and a widget UI toolkit that is similar
to pyqt4, pygtk2 etc.  applications can either be run as javascript
(in a web browser) or on the desktop (using pyjamas-desktop) as
python.  conceptually therefore, pyjamas is similar to adobe AIR -
except that it's python, not ActionScript, and it's entirely free
software.  hurrah!

key changes:

* the python-to-javascript has been significantly reworked, and now
includes a --strict option which adds "python strict" features at the
expense of speed.  to disable these, and obtain speed instead, use
"-O"

* pyjamas-desktop has been merged into the pyjamas distribution, which
includes support for one stable browser engine (XULrunner, the same
engine behind firefox); pywebkitgtk (the engine behind safari and the
iphone) and MSHTML (IE's engine).  pywebkitgtk is useable (but
unfriendly - no DOM exception handling); MSHTML is even less friendly
- COM gets in the way at present, and eats even python exceptions).

there's a lot more that could be said, but you've probably noticed all
the other prerelease notices so 'nuff said, other than: thank you to
the people who've been helping and contributing with testing, patches
and more.

downloads and more information:

http://pypi.python.org/pypi/Pyjamas
http://sf.net/projects/pyjamas
http://code.google.com/p/pyjamas
http://pyjs.org
-- 
http://mail.python.org/mailman/listinfo/python-list

trouble with reload

2009-08-13 Thread Dr. Phillip M. Feldman


According to the Python documentation, 'reload' reloads a previously imported
module (so that changes made via an external editor will be effective). 
But, when I try to use this command, I get the following error message:

TypeError: reload() argument must be module

Any suggestions will be appreciated.
-- 
View this message in context: 
http://www.nabble.com/trouble-with-reload-tp24956946p24956946.html
Sent from the Python - python-list mailing list archive at Nabble.com.

-- 
http://mail.python.org/mailman/listinfo/python-list

Re: i Don't get why it makes trouble

2009-08-13 Thread Jan Kaliszewski


13-08-2009 azrael  wrote:


j

[u'Tata', u'Oriovac', u'PrimorskoGoranska', u'hrvatska', u'Kuna']

len(j)

5
h = """SELECT distinct u.id_ulica, o.id_opcina, z.id_zupanija,  
d.id_drzava, v.id_valuta FROM   ulica as u, opcina as o, zupanija as  
z, drzava as d, valuta as v  WHERE  u.naziv = '%s' AND o.naziv = '%s'  
AND z.naziv = '%s' AND d.naziv = '%s' AND v.naziv = '%s'""" % (j)

Traceback (most recent call last):
  File "", line 1, in 
TypeError: not enough arguments for format string


I want to format the string. the list has five elements and the string
has five placeholder but it wont format the string


j must be a tuple -- so either define it as

(u'Tata', u'Oriovac', u'PrimorskoGoranska', u'hrvatska', u'Kuna')

or when using it, wrap it with tuple() constructor:

h = """...""" % tuple(j)

--
Jan Kaliszewski (zuo) 
--
http://mail.python.org/mailman/listinfo/python-list

Re: trouble with reload


Could you please clarify how you're calling it? E.g.
reload('foo')
or
reload(foo)

?

On Thu, 13 Aug 2009 12:05:26 -0700, Dr. Phillip M. Feldman  
 wrote:


According to the Python documentation, 'reload' reloads a previously  
imported

module (so that changes made via an external editor will be effective).
But, when I try to use this command, I get the following error message:

TypeError: reload() argument must be module

Any suggestions will be appreciated.




--
Rami Chowdhury
"Never attribute to malice that which can be attributed to stupidity" --  
Hanlon's Razor

408-597-7068 (US) / 07875-841-046 (UK) / 0189-245544 (BD)
--
http://mail.python.org/mailman/listinfo/python-list

Re: i Don't get why it makes trouble

2009-08-13 Thread Jan Kaliszewski


Me wrote:


13-08-2009 azrael  wrote:


j

[u'Tata', u'Oriovac', u'PrimorskoGoranska', u'hrvatska', u'Kuna']

len(j)

5
h = """SELECT distinct u.id_ulica, o.id_opcina, z.id_zupanija,  
d.id_drzava, v.id_valuta FROM   ulica as u, opcina as o, zupanija as  
z, drzava as d, valuta as v  WHERE  u.naziv = '%s' AND o.naziv =  
'%s' AND z.naziv = '%s' AND d.naziv = '%s' AND v.naziv = '%s'""" %  
(j)

Traceback (most recent call last):
  File "", line 1, in 
TypeError: not enough arguments for format string


I want to format the string. the list has five elements and the string
has five placeholder but it wont format the string


j must be a tuple -- so either define it as

[snip]

PS. If you use Python 2.6 or newer, better use .format() method
(then you can use also a list):


h = """SELECT distinct u.id_ulica, o.id_opcina, z.id_zupanija, \

... d.id_drzava, v.id_valuta FROM   ulica as u, opcina as o, zupanija as \
... z, drzava as d, valuta as v  WHERE  u.naziv = '{0}' AND o.naziv = \
... '{1}' AND z.naziv = '{2}' AND d.naziv = '{3}' AND v.naziv = '{4}'\
... """.format(*j)


Cheers,
*j

--
Jan Kaliszewski (zuo) 
--
http://mail.python.org/mailman/listinfo/python-list

Re: How to launch a function at regular time intervals ?




Grant Edwards wrote:

On 2009-08-13, Dave Angel  wrote:
  

Grant Edwards wrote:



interval = 5.0  # interval in seconds
next = time.time()

while True:
now = time.time()
if now < next:  
time.sleep(now-next)

print "call_the_function()"
next += interval

That will be accurate over the long term with minimal jitter.
  
  


2) If (occasionally) the function takes longer than the
   specified interval time, my approach does catch-up calls so
   the average remains the same.



I'm still confused -- doesn't mine do that as well?

  
Yep.  I missed it again.  Clearly it does the catchup the next time 
around the while loop.


DaveA
--
http://mail.python.org/mailman/listinfo/python-list

Re: trouble with reload

2009-08-13 Thread David C Ullrich

On Thu, 13 Aug 2009 12:05:26 -0700, Dr. Phillip M. Feldman wrote:

> According to the Python documentation, 'reload' reloads a previously
> imported module (so that changes made via an external editor will be
> effective). But, when I try to use this command, I get the following
> error message:
> 
> TypeError: reload() argument must be module

That would mean that you're trying to reload something
other than a module.

Of course you think you're reloading a module. The problem
is that... oops, since you don't show the code that leads
to this error it's hard to say what the problem is.

> Any suggestions will be appreciated.

-- 
http://mail.python.org/mailman/listinfo/python-list

Re: How to launch a function at regular time intervals ?

2009-08-13 Thread Falcolas

On Aug 12, 3:09 pm, David  wrote:
> Hi all, I'm trying to launch a function at regular time intervals but
> cannot find the way to do it. Here is the code I wrote (time_interval
> is a user defined variable in seconds):
> [snip]
> Has anyone run into a similar problem (and solved it) ?
>
> Thanks for your help

I did - as part of a script where I needed to send load into a system
at a steady rate. I ended up using threading to do the function calls,
since they were not guaranteed to complete before the next interval.

duration_start = time.time()
interval_counter = 0
while time.time() - duration_start < duration:
for thread_count in xrange(numthreads):
threading.Thread(target=exec_thread, kwargs={#snip
unimportant#}).start()
interval_counter += 1
time.sleep((duration_start + (interval * interval_counter)) -
time.time())

Executing this loop with a simple echo and time print showed that
there was no creep over time, and the deviation between intervals was
around 1/100th of a second.

I'm fairly sure I'm creating some gnarly memory leaks and such by not
joining spent threads, but it's been a non-issue in my usage. Adding a
list to keep track of the threads and join on complete threads would
be fairly trivial to implement.

I think for simpler applications, using threading.Timer to kick off
the function would work just as well.

~G
-- 
http://mail.python.org/mailman/listinfo/python-list

Re: How to launch a function at regular time intervals ?


David wrote:

Thanks all for your answers. As suggested by Dave and Frank, I am
indeed looking for the main program to continue running in the
background (I have several functions I want to launch, each at a
predefined time interval). I like Frank's solution, on the paper it
seems it would do what I am looking for, but I cannot succeed in
having it working. I guess I've been stuck with this problem for too
long and can't succeed in using my brain accurately anymore... ;-)

I defined the class as defined by Frank, and I then inserted the
following code in a While True loop, without any other code (the idea
is just to test Frank's solution before really using it in my
program):

func = MyFunction()
func.start()

func.stop()
func.join()

However I'm not getting the expected behavior. It's not taking into
account the 30 sec wait, the function is called again and again
without any time interval... Any idea ?

Again, thanks a lot.


  
Why don't you include the code you're actually trying, instead of just 
trying to describe it.  Frank's class didn't call any function, it just 
had a place to do it.  So we really don't know what you're running, nor 
what about it is wrong.


Perhaps a few well placed print statements?

DaveA
--
http://mail.python.org/mailman/listinfo/python-list

get output of du / ls command - currently ugly code ...


Hi all,

Essentially all I want to know the size of a directory, and the size
of a zipped tarball so that I can compute/report the compression ratio.

The code I have seems hideous, but it seems to work. Surely there is an
easier,more elegant way to do this?

dir_size = os.popen('du -sk somename')
data = dir_size.readlines()
dir_size = int(data[0].split()[0])
print 'dir size: ', dir_size

tar_size = os.popen('ls -s somename.tar.gz')
data = tar_size.readlines()
tar_size = int(data[0].split()[0])
print 'tar size: ', tar_size

Thanks
Esmail

--
http://mail.python.org/mailman/listinfo/python-list

Re: i Don't get why it makes trouble

On 13 kol, 21:12, "Jan Kaliszewski"  wrote:
> Me wrote:
> > 13-08-2009 azrael  wrote:
>
> > j
> >> [u'Tata', u'Oriovac', u'PrimorskoGoranska', u'hrvatska', u'Kuna']
> > len(j)
> >> 5
> > h = """SELECT distinct u.id_ulica, o.id_opcina, z.id_zupanija,  
> > d.id_drzava, v.id_valuta FROM   ulica as u, opcina as o, zupanija as  
> > z, drzava as d, valuta as v  WHERE  u.naziv = '%s' AND o.naziv =  
> > '%s' AND z.naziv = '%s' AND d.naziv = '%s' AND v.naziv = '%s'""" %  
> > (j)
> >> Traceback (most recent call last):
> >>   File "", line 1, in 
> >> TypeError: not enough arguments for format string
>
> >> I want to format the string. the list has five elements and the string
> >> has five placeholder but it wont format the string
>
> > j must be a tuple -- so either define it as
>
> [snip]
>
> PS. If you use Python 2.6 or newer, better use .format() method
> (then you can use also a list):
>
> >>> h = """SELECT distinct u.id_ulica, o.id_opcina, z.id_zupanija, \
>
> ... d.id_drzava, v.id_valuta FROM   ulica as u, opcina as o, zupanija as \
> ... z, drzava as d, valuta as v  WHERE  u.naziv = '{0}' AND o.naziv = \
> ... '{1}' AND z.naziv = '{2}' AND d.naziv = '{3}' AND v.naziv = '{4}'\
> ... """.format(*j)
>
> Cheers,
> *j
>
> --
> Jan Kaliszewski (zuo) 

Thanks Worked fine for me. I was a freakin idiot. I forgot about using
a tuple. damn lists :D

Thanks for the debuginig of my thoughts and actions.

thnx
-- 
http://mail.python.org/mailman/listinfo/python-list

Re: Help newbie with how to call a source command

Joni Lee wrote:

Hi all,

I'm landing here because I need some help that I couldn't get through it.
Question 1.
I want to call a source command from python script. It will source some variables enviroment for further commands. I tried the following which did not work

os.sys('source '+source_text)
call(['source',source_text], shell=True)
commands.getoutput('source '+source_text)

Anyone have experiences with this? Because I'm very new to this world so a details reply is really appreciated!!! thank you very much

Question 2.

I call a shell command from python, this time it runs a script which runs some ruby
scripts. And the error returns: "ruby: command not found"

Thank you again

1) You cannot do "source" from Python. It's a shell command whose very
nature is to remember some environment variables for the duration of
that particular shell. So once it returns to your python program,
they're lost.

However, if you just need those variables for invocations of the same
shell, you have a couple of choices. You can parse the file yourself,
and set up an environment dictionary, and pass that when you invoke
subsequent shells.

Or you can build a script on the fly, prepending whatever script you're
planning to run with that source_text file.

2) In this question, and in general, you need to specify the Python
version, the OS environment, the particular Python code you used to
launch the shell, the contents of the script, and the results you saw.
Use copy and paste, don't just paraphrase.

And in a case like this one, somebody familiar with the environment
(Ruby on Unix?) will probably have other questions: environment
dictionary passed to the shell, did you get a Ruby startup prompt? Or
whatever.

DaveA

--
http://mail.python.org/mailman/listinfo/python-list

Re: get output of du / ls command - currently ugly code ...

2009-08-13 Thread [email protected]

On Aug 13, 8:28 pm, Esmail  wrote:
> Hi all,
>
> Essentially all I want to know the size of a directory, and the size
> of a zipped tarball so that I can compute/report the compression ratio.
>
> The code I have seems hideous, but it seems to work. Surely there is an
> easier,more elegant way to do this?
>
>      dir_size = os.popen('du -sk somename')
>      data = dir_size.readlines()
>      dir_size = int(data[0].split()[0])
>      print 'dir size: ', dir_size
>
>      tar_size = os.popen('ls -s somename.tar.gz')
>      data = tar_size.readlines()
>      tar_size = int(data[0].split()[0])
>      print 'tar size: ', tar_size
>
> Thanks
> Esmail

Try using os.path.getsize(somename.tar.gz)
-- 
http://mail.python.org/mailman/listinfo/python-list

Re: i Don't get why it makes trouble

2009-08-13 Thread Philip Semanchuk



On Aug 13, 2009, at 2:56 PM, azrael wrote:


j

[u'Tata', u'Oriovac', u'PrimorskoGoranska', u'hrvatska', u'Kuna']

len(j)

5
h = """SELECT distinct u.id_ulica, o.id_opcina, z.id_zupanija,  
d.id_drzava, v.id_valuta FROM   ulica as u, opcina as o, zupanija  
as z, drzava as d, valuta as v  WHERE  u.naziv = '%s' AND o.naziv  
= '%s' AND z.naziv = '%s' AND d.naziv = '%s' AND v.naziv =  
'%s'""" % (j)

Traceback (most recent call last):
 File "", line 1, in 
TypeError: not enough arguments for format string


Hi azrael,
You already have an answer to your question so I won't address that. I  
want to point out that this is a dangerous way to build SQL statements.


For instance, what happens if someone enters a city name of L'viv?   
Your SQL will break due to mismatched single quotes. This kind of code  
is vulnerable to SQL injection attacks:

http://en.wikipedia.org/wiki/SQL_injection

Parameterized SQL is safer. Googling for 'parameterized SQL Python'  
should find some examples for you.


Good luck
Philip
--
http://mail.python.org/mailman/listinfo/python-list

Re: get output of du / ls command - currently ugly code ...


[email protected] wrote:

On Aug 13, 8:28 pm, Esmail  wrote:

Hi all,

Essentially all I want to know the size of a directory, and the size
of a zipped tarball so that I can compute/report the compression ratio.




 dir_size = os.popen('du -sk somename')
 data = dir_size.readlines()
 dir_size = int(data[0].split()[0])
 print 'dir size: ', dir_size



Hi,

 > Try using os.path.getsize(somename.tar.gz)

Beautiful! .. that takes care of the tarball .. but it doesn't seem to
work for reporting the total size of the directory. Any suggestions how
to do that in a nicer way?

I just looked through os.path.* and there doesn't seem to be a function
to report what "du -sb" would.

Thanks for your help,

Esmail

--
http://mail.python.org/mailman/listinfo/python-list

Re: get output of du / ls command - currently ugly code ...

2009-08-13 Thread Albert Hopkins

On Thu, 2009-08-13 at 15:28 -0400, Esmail wrote:
> Hi all,
> 
> Essentially all I want to know the size of a directory, and the size
> of a zipped tarball so that I can compute/report the compression ratio.
> 
> The code I have seems hideous, but it seems to work. Surely there is an
> easier,more elegant way to do this?
> 
>  dir_size = os.popen('du -sk somename')
>  data = dir_size.readlines()
>  dir_size = int(data[0].split()[0])
>  print 'dir size: ', dir_size
> 
>  tar_size = os.popen('ls -s somename.tar.gz')
>  data = tar_size.readlines()
>  tar_size = int(data[0].split()[0])
>  print 'tar size: ', tar_size
> 

I don't know about "easier", but a more elegant way is to not use
os.popen() and to use Python's functions os.path.getsize (or os.stat)
and os.walk (or os.path.walk) to achieve this.

In fact if you look at the docstring for os.walk there is an example
that almost does what you're doing with du, but is cross-platform and
not dependent on shelling a process and scraping its stdout.

-a

-- 
http://mail.python.org/mailman/listinfo/python-list

Re: i Don't get why it makes trouble

2009-08-13 Thread Benjamin Kaplan

On Thu, Aug 13, 2009 at 4:09 PM, Philip Semanchuk wrote:

>
> On Aug 13, 2009, at 2:56 PM, azrael wrote:
>
>  j
>
 [u'Tata', u'Oriovac', u'PrimorskoGoranska', u'hrvatska', u'Kuna']
>>
>>> len(j)
>
 5
>>
>>> h = """SELECT distinct u.id_ulica, o.id_opcina, z.id_zupanija,
> d.id_drzava, v.id_valuta FROM   ulica as u, opcina as o, zupanija as z,
> drzava as d, valuta as v  WHERE  u.naziv = '%s' AND o.naziv = '%s' AND
> z.naziv = '%s' AND d.naziv = '%s' AND v.naziv = '%s'""" % (j)
>
 Traceback (most recent call last):
>>  File "", line 1, in 
>> TypeError: not enough arguments for format string
>>
>
> Hi azrael,
> You already have an answer to your question so I won't address that. I want
> to point out that this is a dangerous way to build SQL statements.
>
> For instance, what happens if someone enters a city name of L'viv?  Your
> SQL will break due to mismatched single quotes. This kind of code is
> vulnerable to SQL injection attacks:
> http://en.wikipedia.org/wiki/SQL_injection
>

No explanation of SQL injection is complete without a link to the relevant
XKCD.

http://xkcd.com/327/


>
> Parameterized SQL is safer. Googling for 'parameterized SQL Python' should
> find some examples for you.
>
> Good luck
> Philip
> --
> http://mail.python.org/mailman/listinfo/python-list
>
-- 
http://mail.python.org/mailman/listinfo/python-list

[RELEASED] Python 3.1.1 Release Candidate

2009-08-13 Thread Benjamin Peterson

On behalf of the Python development team, I'm pleased to announce the first
release candidate of Python 3.1.1.

This bug fix release fixes many normal bugs and several critical ones including
potential data corruption in the io library.  The final version should be out
within the next week.

Python 3.1 focuses on the stabilization and optimization of the features and
changes that Python 3.0 introduced.  For example, the new I/O system has been
rewritten in C for speed.  File system APIs that use unicode strings now handle
paths with undecodable bytes in them. Other features include an ordered
dictionary implementation, a condensed syntax for nested with statements, and
support for ttk Tile in Tkinter.  For a more extensive list of changes in 3.1,
see http://doc.python.org/3.1/whatsnew/3.1.html or Misc/NEWS in the Python
distribution.

To download Python 3.1.1 visit:

 http://www.python.org/download/releases/3.1/

The 3.1 documentation can be found at:

 http://docs.python.org/3.1

Bugs can always be reported to:

 http://bugs.python.org


Enjoy!

--
Benjamin Peterson
Release Manager
benjamin at python.org
(on behalf of the entire python-dev team and 3.1.1's contributors)
-- 
http://mail.python.org/mailman/listinfo/python-list

need help calculating point between two coordinates.

2009-08-13 Thread PeteDK

Hi there

I'am working on a route comparison tool for carpools.

The route comparison is based on 'steps' retrieved from google maps
GDirection. These steps vary in length and i use the coordinates at
the beginning of each "step". However, sometimes the distance of these
steps is too long(ex. driving 30-40 km. on the freeway). Therefore i
would like to calculate/find the coordinate located in between two
given coordinates.
Lets say one step starts at:
56.043185,9.922714
and ends at:
56.234287,9.864521

I would then like to calculate the point right in the middle of these
coordinates.

I use the haversine form to calculate the distance between
coordinates, but im not sure whether or not this can be used for the
same purpose.
http://www.mpi.nl/world/persons/private ... versine.py

I apologize if this thread has been posted the wrong place:)

any help is greatly appreciated!

kind regards.

Pete
-- 
http://mail.python.org/mailman/listinfo/python-list

Re: get output of du / ls command - currently ugly code ...


Albert Hopkins wrote:


I don't know about "easier", but a more elegant way is to not use
os.popen() and to use Python's functions os.path.getsize (or os.stat)
and os.walk (or os.path.walk) to achieve this.

In fact if you look at the docstring for os.walk there is an example
that almost does what you're doing with du, but is cross-platform and
not dependent on shelling a process and scraping its stdout.


Thanks Albert, I'll take a look,

Esmail

--
http://mail.python.org/mailman/listinfo/python-list

Re: i Don't get why it makes trouble

On 13 kol, 22:09, Philip Semanchuk  wrote:
> On Aug 13, 2009, at 2:56 PM, azrael wrote:
>
>  j
> > [u'Tata', u'Oriovac', u'PrimorskoGoranska', u'hrvatska', u'Kuna']
>  len(j)
> > 5
>  h = """SELECT distinct u.id_ulica, o.id_opcina, z.id_zupanija,  
>  d.id_drzava, v.id_valuta FROM   ulica as u, opcina as o, zupanija  
>  as z, drzava as d, valuta as v  WHERE  u.naziv = '%s' AND o.naziv  
>  = '%s' AND z.naziv = '%s' AND d.naziv = '%s' AND v.naziv =  
>  '%s'""" % (j)
> > Traceback (most recent call last):
> >  File "", line 1, in 
> > TypeError: not enough arguments for format string
>
> Hi azrael,
> You already have an answer to your question so I won't address that. I  
> want to point out that this is a dangerous way to build SQL statements.
>
> For instance, what happens if someone enters a city name of L'viv?  
> Your SQL will break due to mismatched single quotes. This kind of code  
> is vulnerable to SQL injection 
> attacks:http://en.wikipedia.org/wiki/SQL_injection
>
> Parameterized SQL is safer. Googling for 'parameterized SQL Python'  
> should find some examples for you.
>
> Good luck
> Philip

I know Already. This is sopussed to be a small office application
connecting on a LAN mysql server with no web connection. Thank you
anyway
-- 
http://mail.python.org/mailman/listinfo/python-list

Idle text wrap

2009-08-13 Thread goldtech

Hi,

I'm using Idle interactive shell. Actually Idle-Spoon which has a few
nice extensions and Python 2.6 on Linux. When I

 print str_value + "\n"

Where str_value is for example a string of 120 chars.

I notice that the lines seem to get hard wrapped at around 80. Is
there a way I can config it to either wrap to the window, or for a
higher amount before wrapping?

Thanks.
-- 
http://mail.python.org/mailman/listinfo/python-list

Re: i Don't get why it makes trouble

2009-08-13 Thread Philip Semanchuk



On Aug 13, 2009, at 6:00 PM, azrael wrote:


On 13 kol, 22:09, Philip Semanchuk  wrote:

On Aug 13, 2009, at 2:56 PM, azrael wrote:


j

[u'Tata', u'Oriovac', u'PrimorskoGoranska', u'hrvatska', u'Kuna']

len(j)

5

h = """SELECT distinct u.id_ulica, o.id_opcina, z.id_zupanija,
d.id_drzava, v.id_valuta FROM   ulica as u, opcina as o, zupanija
as z, drzava as d, valuta as v  WHERE  u.naziv = '%s' AND o.naziv
= '%s' AND z.naziv = '%s' AND d.naziv = '%s' AND v.naziv =
'%s'""" % (j)

Traceback (most recent call last):
 File "", line 1, in 
TypeError: not enough arguments for format string


Hi azrael,
You already have an answer to your question so I won't address  
that. I
want to point out that this is a dangerous way to build SQL  
statements.


For instance, what happens if someone enters a city name of L'viv?
Your SQL will break due to mismatched single quotes. This kind of  
code

is vulnerable to SQL injection 
attacks:http://en.wikipedia.org/wiki/SQL_injection

Parameterized SQL is safer. Googling for 'parameterized SQL Python'
should find some examples for you.

Good luck
Philip


I know Already. This is sopussed to be a small office application
connecting on a LAN mysql server with no web connection. Thank you
anyway


You're welcome. I'm glad you are aware. You're ahead of a lot of  
developers out there.


I encourage you to at least think about using parameterized SQL anyway  
because you never know when someone (maybe even you!) will copy &  
paste your code, or use your library without realizing that it was  
"internal use only". It's usually just as easy as building SQL strings  
anyway.


And besides, what about L'viv? =)

Good luck with whatever choice you make
Philip




--
http://mail.python.org/mailman/listinfo/python-list

implementing descriptors

2009-08-13 Thread dippim

I am new to Python and I have a question about descriptors.  If I have
a class as written below, is there a way to use descriptors to be
certain that the datetime in start is always before the one in end?

class foo(object):
   def __init__(self,a = None,b = None)
  self.start = a
  self.end = b

from datetime import datetime
c = datetime(2009,8,13,6,15,0)
d = datetime(2009,8,14,12,0,0)
afoo = foo(c,d)

For instance, if the following code were run, I would like to instance
of foo to switch the start and end times.

afoo.start = datetime(2010,8,13,6,15,0)

I was thinking of using the __set__ descriptor to catch the assignment
and reverse the values if necessary, but I can't figure out how to
determine which values is being set.

Thanks for the help!

David
-- 
http://mail.python.org/mailman/listinfo/python-list

Re: How to launch a function at regular time intervals ?

2009-08-13 Thread David

On 13 août, 21:28, Dave Angel  wrote:
> David wrote:
> > Thanks all for your answers. As suggested by Dave and Frank, I am
> > indeed looking for the main program to continue running in the
> > background (I have several functions I want to launch, each at a
> > predefined time interval). I like Frank's solution, on the paper it
> > seems it would do what I am looking for, but I cannot succeed in
> > having it working. I guess I've been stuck with this problem for too
> > long and can't succeed in using my brain accurately anymore... ;-)
>
> > I defined the class as defined by Frank, and I then inserted the
> > following code in a While True loop, without any other code (the idea
> > is just to test Frank's solution before really using it in my
> > program):
>
> >     func = MyFunction()
> >     func.start()
>
> >     func.stop()
> >     func.join()
>
> > However I'm not getting the expected behavior. It's not taking into
> > account the 30 sec wait, the function is called again and again
> > without any time interval... Any idea ?
>
> > Again, thanks a lot.
>
> Why don't you include the code you're actually trying, instead of just
> trying to describe it.  Frank's class didn't call any function, it just
> had a place to do it.  So we really don't know what you're running, nor
> what about it is wrong.
>
> Perhaps a few well placed print statements?
>
> DaveA

Yes, I guess it would be more simple. Here is really what I am trying
to do. I simplified the functions, but the purpose is to write some
text in a local file every x seconds (here, I'm just writing the
timestamp, i.e. a string representing the date & time, every 10
seconds) and to transfer this file to a distant server via FTP every y
seconds (20 seconds in the example below). My code is a little bit
more complicated because each time I transfer the file, I delete the
local file which is then recreated when data is written, but for
simplicity I left this out in the code below. So, here is the code
I've been using to test Frank's code. I've been struggling with using
or not a While True loop or not, and everything I try seems to run
into issues.

import threading
from datetime import datetime
import ftplib

class CFtpConnection:
"""FTP Connection parameters"""
def __init__(self, host, port, timeout, user, passwd):
self.host = ""
self.port = 21
self.timeout = 60
self.user = ""
self.passwd = ""

class CStoreData(threading.Thread):
"""Write timestamp in a file every 10 seconds in separate
thread"""

def __init__(self, timestamp):
threading.Thread.__init__(self)
self.event = threading.Event()
self.timestamp = timestamp

def run(self):
while not self.event.is_set():
file_handler = open("Test.txt", 'a')
file_handler.write(self.timestamp.strftime("%y%m%d%H%M%S
\n"))
file_handler.close()
self.event.wait(10)

def stop(self):
self.event.set()

class CTransferData(threading.Thread):
"""Transfer timestamp file every 20 seconds in separate thread"""

def __init__(self, ftp_connection):
threading.Thread.__init__(self)
self.event = threading.Event()
self.ftp_connection = ftp_connection

def run(self):
while not self.event.is_set():
file_handler = open("Test.txt", 'r')
Ftp_handler = ftplib.FTP('')
Ftp_handler.connect(self.ftp_connection.host,
self.ftp_connection.port, self.ftp_connection.timeout)
Ftp_handler.login(self.ftp_connection.user,
self.ftp_connection.passwd)
Ftp_handler.storbinary("STOR Test.txt", file_handler)
file_handler.close()
Ftp_handler.close()
self.event.wait(20)

def stop(self):
self.event.set()

ftp_connection = CFtpConnection("", 21, 60, "", "")
ftp_connection.host = '127.0.0.1'
ftp_connection.user = "admin"
ftp_connection.passwd = "admin"

while(1):
  timestamp = datetime.now()
  func_store_data = CStoreData(timestamp)
  func_store_data.start()

  func_transfer_data = CTransferData(ftp_connection)
  func_transfer_data.start()

func_store_data.stop()
func_store_data.join()

func_transfer_data.stop()
func_transfer_data.join()
-- 
http://mail.python.org/mailman/listinfo/python-list

Re: implementing descriptors

2009-08-13 Thread Mark Lawrence


dippim wrote:

I am new to Python and I have a question about descriptors.  If I have
a class as written below, is there a way to use descriptors to be
certain that the datetime in start is always before the one in end?

class foo(object):
   def __init__(self,a = None,b = None)
  self.start = a
  self.end = b

from datetime import datetime
c = datetime(2009,8,13,6,15,0)
d = datetime(2009,8,14,12,0,0)
afoo = foo(c,d)

For instance, if the following code were run, I would like to instance
of foo to switch the start and end times.

afoo.start = datetime(2010,8,13,6,15,0)

I was thinking of using the __set__ descriptor to catch the assignment
and reverse the values if necessary, but I can't figure out how to
determine which values is being set.

Thanks for the help!

David

Take a look at the example given here.
http://users.rcn.com/python/download/Descriptor.htm

--
Kindest regards.

Mark Lawrence.

--
http://mail.python.org/mailman/listinfo/python-list

Re: PIL and Python

2009-08-13 Thread Martin

On Aug 13, 1:55 pm, "[email protected]" 
wrote:
> Hello !
> I want use python to change the "note" from .jpeg files .
> What is the functions on PIL how make this ?
> Thank you !

What do u mean by the note?
-- 
http://mail.python.org/mailman/listinfo/python-list

Re: implementing descriptors

2009-08-13 Thread Emile van Sebille


On 8/13/2009 3:17 PM dippim said...

I am new to Python and I have a question about descriptors.  If I have
a class as written below, is there a way to use descriptors to be
certain that the datetime in start is always before the one in end?

class foo(object):
   def __init__(self,a = None,b = None)
  self.start = a
  self.end = b

from datetime import datetime
c = datetime(2009,8,13,6,15,0)
d = datetime(2009,8,14,12,0,0)
afoo = foo(c,d)

For instance, if the following code were run, I would like to instance
of foo to switch the start and end times.

afoo.start = datetime(2010,8,13,6,15,0)

I was thinking of using the __set__ descriptor to catch the assignment
and reverse the values if necessary, 


why not...


class foo(object):
   def __init__(self,a = None,b = None)
  self.start = min(a,b)
  self.end = max(a,b)


Emile

--
http://mail.python.org/mailman/listinfo/python-list

Re: need help calculating point between two coordinates.


PeteDK wrote:

Hi there

I'am working on a route comparison tool for carpools.

The route comparison is based on 'steps' retrieved from google maps
GDirection. These steps vary in length and i use the coordinates at
the beginning of each "step". However, sometimes the distance of these
steps is too long(ex. driving 30-40 km. on the freeway). Therefore i
would like to calculate/find the coordinate located in between two
given coordinates.
Lets say one step starts at:
56.043185,9.922714
and ends at:
56.234287,9.864521

I would then like to calculate the point right in the middle of these
coordinates.

I use the haversine form to calculate the distance between
coordinates, but im not sure whether or not this can be used for the
same purpose.
http://www.mpi.nl/world/persons/private ... versine.py

I apologize if this thread has been posted the wrong place:)

any help is greatly appreciated!

kind regards.

Pete

  
For the distances you're talking about, those coordinates are very close 
to linear.  So to find the midpoint, just average the coordinates.  You 
might be off by half a km, but roads bend more than that.


DaveA

--
http://mail.python.org/mailman/listinfo/python-list

Python "and" behavior

2009-08-13 Thread goldtech

Could you explain or link me to an explanation of this? Been using
Python for a while but not sure I understand what's happening below.
Thanks.


>>> ss=1 and "f"
>>> ss
'f'
>>> ss=0 and "f"
>>> ss
0
>>>
-- 
http://mail.python.org/mailman/listinfo/python-list

Re: Python "and" behavior

2009-08-13 Thread Gary Herron


goldtech wrote:

Could you explain or link me to an explanation of this? Been using
Python for a while but not sure I understand what's happening below.
Thanks.


  

ss=1 and "f"
ss


'f'
  

ss=0 and "f"
ss


0
  


Python's Boolean operators don't turn arbitrary values into True and 
False values.  If you use it in any conditional, you'll get the same 
result as if it did, but it is occasionally it's nice to get the actual 
values used in the "and" instead of having the value distilled down to a 
True/False.



From the Python manual: 


These are the Boolean operations, ordered by ascending priority:

Operation   Result  Notes
|x or y|if x is false, then y, else x   (1)
|x and y|   if x is false, then x, else y   (1)
|not x| if x is false, then |True|, else |False|(2)

Notes:

*(1)*
   These only evaluate their second argument if needed for their outcome.

*(2)*
   "not" has a lower priority than non-Boolean operators, so |not a ==
   b| is interpreted as |not (a == b)|, and |a == not b| is a syntax
   error.


-- 
http://mail.python.org/mailman/listinfo/python-list

Re: Python "and" behavior

2009-08-13 Thread Mensanator

On Aug 13, 7:36 pm, goldtech  wrote:
> Could you explain or link me to an explanation of this? Been using
> Python for a while but not sure I understand what's happening below.
> Thanks.
>
>
>
>
>
> >>> ss=1 and "f"
> >>> ss
> 'f'
> >>> ss=0 and "f"
> >>> ss
> 0


Does this help?

>>> ss = True and 'f'
>>> ss
'f'
>>> ss = False and 'e'
>>> ss
False


-- 
http://mail.python.org/mailman/listinfo/python-list

Re: Python "and" behavior

2009-08-13 Thread Stephen Hansen

>
> Could you explain or link me to an explanation of this? Been using
> Python for a while but not sure I understand what's happening below.
> Thanks.
>
> >>> ss=1 and "f"
> >>> ss
> 'f'
> >>> ss=0 and "f"
> >>> ss
> 0
> >>>


The "and" and "or" operators in Python are actually not true boolean
operators: they operate on the more fundamental interpretation of Truth that
Python uses (and that 'if' for example uses) that goes back before Python
got actual boolean True/False values.
"x and y" evaluates first x; if it is false, its value is returned.
Otherwise, the value of y is returned.

"x or y" evaluates first x; if it is true, its value is returned. Otherwise,
the value of y is returned.

Python's idea of "true" verses "false" isn't the same as True and False.
It's been described as "something" verses "nothing", as in Python the
following are considered false: False, None, numeric 0 (in all types of
numbers), empty strings, empty containers (lists, tuples, dictionaries,
sets). Everything else is True. Instances of any class are True by default,
but they can have a __nonzero__ operation on them to override that.

So, every value has an innate 'truthfulness' about it: the 'if' statement
bases its decision on that truthfulness. In the context of truthfulness, the
string "hello" is just as true as the singleton True. So, if you do "x and
y", if 'x' is a false value... then 'x' is returned-- as 'x' is just as
false as the singleton False. Both are different ways of saying 'false' in
logical operations.

Lots of people don't like this. Lots of people do. Some people want it to be
pure-true boolean algebra, have them return True/False always-- some people
have even argued for "if" only branching on True/False values. The fact of
the matter is, this is all just a fundamental part of Python that pre-dates
it ever having true boolean values, and is never gonna go away.

There's some useful properties to it, like:

value = opt or "default"

In this case, if opt was set to a something, it'll end up in value.
Otherwise, "default" will. Of course that's only useful where a opt would
never have a blank string or 0 or such in it naturally.

The poor-man's ternary operator was commonly used before Python got a proper
one:

value = x and "Yes" or "No"

The construct had some limits(namely, the value in the "Yes" part of the
expression must be truthy), but is still useful in a lot of situations. If
"x" would evaluate true, then value would be set to "Yes". Otherwise, it'd
be set to "No".

HTH,

--Stephen
-- 
http://mail.python.org/mailman/listinfo/python-list

Re: Python "and" behavior

2009-08-13 Thread MRAB


Gary Herron wrote:

goldtech wrote:

Could you explain or link me to an explanation of this? Been using
Python for a while but not sure I understand what's happening below.
Thanks.


  

ss=1 and "f"
ss


'f'
  

ss=0 and "f"
ss


0
  


Python's Boolean operators don't turn arbitrary values into True and 
False values.  If you use it in any conditional, you'll get the same 
result as if it did, but it is occasionally it's nice to get the actual 
values used in the "and" instead of having the value distilled down to a 
True/False.



 >From the Python manual: 


These are the Boolean operations, ordered by ascending priority:

Operation   Result  Notes
|x or y|if x is false, then y, else x   (1)
|x and y|   if x is false, then x, else y   (1)
|not x| if x is false, then |True|, else |False|(2)


The Pythonic table would be:

Operation   Result
|x or y|x if x else y
|x and y|   y if x else x
|not x| False if x else False

:-)
--
http://mail.python.org/mailman/listinfo/python-list

Re: fileinput

On Aug 13, 7:50 am, Dave Angel  wrote:
> naaman wrote:
> > On Aug 12, 1:35 pm, Dave Angel  wrote:
>
> >> naaman wrote:
>
> >>> I'm writing my first Python script and
> >>> I want to use fileinput to open a file in r+ mode.
> >>> Tried fileinput.input(sys.argv[1:],"r+") but that didn't work.
> >>> ANy ideas?
>
> >>> Need to find and overwrite a line in a file several times.
> >>> I can do it using open and seek() etc. but was wondering if I can use
> >>> fileinput.
>
> >>> thanks;
>
> >> I haven't used it, but check out the 'inplace' keyword parameter.
>
> >> DaveA
>
> > I've only Python for a week so I'm not sure what inplace does
>
> You should read the docs for it
>     (http://www.python.org/doc/2.6.2/library/fileinput.html ),
> but it's not very clear to me either  So I dug up an example on the web:
>      (ref:  http://effbot.org/librarybook/fileinput.htm)
>
> import fileinput, sys
>
> for line in fileinput.input(inplace=1):
>     # /convert Windows/DOS text files to Unix files/
>     if line[-2:] == "\r\n":
>         line = line[:-2] + "\n"
>     sys.stdout.write(line)
>
> The inplace argument tells it to create a new file with the same name as
> the original (doing all the necessary nonsense with using a scratch
> file, and renaming/deleting) for each file processed.  Stdout is pointed
> to that new version of the file.  Notice that you have to explicitly
> write everything you want to wind up in the file -- if a given line is
> to remain unchanged, you just write "line" directly.
>
> If you're new to Python, I do not recommend trying to do open/seek to
> update a text file in place, especially if you're in DOS.  There are
> lots of traps.  the inplace method of fileinput avoids these by
> implicitly creating temp files and handling the details for you, which
> probably works great if you're dealing with text, in order.
>
> DaveA

Thanks Dave. I'll check that out
-- 
http://mail.python.org/mailman/listinfo/python-list

A Exhibition Of Tech Geekers Incompetence: Emacs whitespace-mode

2009-08-13 Thread Xah Lee

• A Exhibition Of Tech Geekers Incompetence: Emacs whitespace-mode
  http://xahlee.org/UnixResource_dir/writ/emacs_whitespace-mode_problems.html

plane text version follows:
--

A Exhibition Of Tech Geekers Incompetence: Emacs whitespace-mode

Xah Lee, 2009-08-13

Just wanted to express some frustration with whitespace-mode.

Emacs 23, just released, has this whitespace-mode feature. It renders
spaces, tabs, newlines characters with a visible glyph. This feature,
is in Microsoft Word since about 1992.

This feature is important in practical ways. For example, when you
work with “tab separated line” files (CSV) that's a common format for
importing/exporting address books or spreadsheets. It's also important
in whitespace-significant langs such as Python. Or, in text processing
when placement of space and tabs matters in the output.

All i wanted, is to make Space and Tab and Newline chars visible.

However, the emacs whitespace-mode does much more than that. It is
designed for tech geeking control freaks to tune every aspect of white
space in his source code. The mode is filled with bells and whistles.
It distinguishes tabs mixed with spaces, EOLs mixed with spaces, EOLs
at beginning of file, EOLs at end of file, run on spaces at end of
line, lines that has nothing to do with white spaces but is simply
longer than 80 chars, etc. Each of these is rendered with different
foreground, background, colors, so that they cannot possibly escape
the notices of control freaks.

By default, most of these are on, so that, when you turn on the mode,
most reasonable clean source code become this colorful rainbow
unreadable fuck.

I tried to tune it, with my 10 years of emacs of fucking 16 hours of
using per day, and 3 years of elisp coding experience. But, after a
hour, it's confusion hell sans avail.

O, that Alex idiot with his emacswiki, refused to lead emacswiki into
any readable state. All he can think about is my social skills. (See:
Problems of Emacswiki.)

What the fuck motherfuck. Hi tech geekers, coding freaks, social
science ignoramus fucks, basic economics illiterate FSF fucks, freedom
abusing selfish ideologists fucks, Richard Stallman propagandist fuck,
we-try-to-be-easy-to-use linuxer idioting fucks, FUCK U.

  Xah
∑ http://xahlee.org/

☄
-- 
http://mail.python.org/mailman/listinfo/python-list

new version TimingAnalyzer

2009-08-13 Thread timinganalyzer

Hi All,

   1.Added a new User Delay and Constraint Editor panel. You can add,
delete, or update User Delays or Constraints.
   2 .These User Delays and User Constraints are saved at the top of
the .tim file.
   3.Changing a User Delay or User Constraint updates every one of the
same type in the diagram.
   4.Files created with previous versions are converted to this new
format when saved.
   5.Added Python Interpreter, Jython 2.5. Now you can write scripts
in Python.
   6.Execute Python scripts using the same script dialog for the
beanshell scripts or from Jython command line window.
   7.Included start_app.py script in the install directory that will
start the TimingAnalyzer from a Jython command line window.
   8.Updated spice_pwl.bsh. This beanshell script generates spice
piece wise linear test vectors for DigitalBus.
   9.Included dff.py. This Python script shows how to generate a
timing diagram for a D Flip Flop.

Anyone interested in helping convert the Java scripts (in the scripts
dir) to Python should let me know.
Dan Fabrizio

www.timing-diagrams.com
-- 
http://mail.python.org/mailman/listinfo/python-list

Re: i Don't get why it makes trouble

On 14 kol, 00:14, Philip Semanchuk  wrote:
> On Aug 13, 2009, at 6:00 PM, azrael wrote:
>
>
>
>
>
> > On 13 kol, 22:09, Philip Semanchuk  wrote:
> >> On Aug 13, 2009, at 2:56 PM, azrael wrote:
>
> >> j
> >>> [u'Tata', u'Oriovac', u'PrimorskoGoranska', u'hrvatska', u'Kuna']
> >> len(j)
> >>> 5
> >> h = """SELECT distinct u.id_ulica, o.id_opcina, z.id_zupanija,
> >> d.id_drzava, v.id_valuta FROM   ulica as u, opcina as o, zupanija
> >> as z, drzava as d, valuta as v  WHERE  u.naziv = '%s' AND o.naziv
> >> = '%s' AND z.naziv = '%s' AND d.naziv = '%s' AND v.naziv =
> >> '%s'""" % (j)
> >>> Traceback (most recent call last):
> >>>  File "", line 1, in 
> >>> TypeError: not enough arguments for format string
>
> >> Hi azrael,
> >> You already have an answer to your question so I won't address  
> >> that. I
> >> want to point out that this is a dangerous way to build SQL  
> >> statements.
>
> >> For instance, what happens if someone enters a city name of L'viv?
> >> Your SQL will break due to mismatched single quotes. This kind of  
> >> code
> >> is vulnerable to SQL injection 
> >> attacks:http://en.wikipedia.org/wiki/SQL_injection
>
> >> Parameterized SQL is safer. Googling for 'parameterized SQL Python'
> >> should find some examples for you.
>
> >> Good luck
> >> Philip
>
> > I know Already. This is sopussed to be a small office application
> > connecting on a LAN mysql server with no web connection. Thank you
> > anyway
>
> You're welcome. I'm glad you are aware. You're ahead of a lot of  
> developers out there.
>
> I encourage you to at least think about using parameterized SQL anyway  
> because you never know when someone (maybe even you!) will copy &  
> paste your code, or use your library without realizing that it was  
> "internal use only". It's usually just as easy as building SQL strings  
> anyway.
>
> And besides, what about L'viv? =)
>
> Good luck with whatever choice you make
> Philip

Currently I am working on just a prototype to show what is possible to
be done to get me some fundings for my future work. after that I will
get over to an SQL Alchemy. It's ORM will take over this business for
me.

A lot of people a not aware of SQL injection. My friend from college
asked me and a couple of other guys for Pen testing of an website. His
SQL injection mistake made him an epic fail.

Thanks
-- 
http://mail.python.org/mailman/listinfo/python-list

Re: csv.DictWriter.write_header()

2009-08-13 Thread Chris Rebert

On Wed, Aug 12, 2009 at 4:45 PM, Alan G Isaac wrote:
> Given a csv.DictWriter instance `dw`
> I think it would be nice to be able to
> say dw.write_header()
> instead of
> dw.writer.writerow(dw.fieldnames)
>
> Good idea?

Maybe. You could file a bug: http://bugs.python.org/

Cheers,
Chris
-- 
http://blog.rebertia.com
-- 
http://mail.python.org/mailman/listinfo/python-list

something like perl's Mail::GPG ?

2009-08-13 Thread akonsu

hello,

i am looking for a module with functionality similar to that of the
Perl's Mail::GPG package. I need to verify multipart emails that are
PGP-signed.

thanks for any advice
konstantin
-- 
http://mail.python.org/mailman/listinfo/python-list

Re: fileinput

On Aug 13, 7:50 am, Dave Angel  wrote:
> naaman wrote:
> > On Aug 12, 1:35 pm, Dave Angel  wrote:
>
> >> naaman wrote:
>
> >>> I'm writing my first Python script and
> >>> I want to use fileinput to open a file in r+ mode.
> >>> Tried fileinput.input(sys.argv[1:],"r+") but that didn't work.
> >>> ANy ideas?
>
> >>> Need to find and overwrite a line in a file several times.
> >>> I can do it using open and seek() etc. but was wondering if I can use
> >>> fileinput.
>
> >>> thanks;
>
> >> I haven't used it, but check out the 'inplace' keyword parameter.
>
> >> DaveA
>
> > I've only Python for a week so I'm not sure what inplace does
>
> You should read the docs for it
>     (http://www.python.org/doc/2.6.2/library/fileinput.html ),
> but it's not very clear to me either  So I dug up an example on the web:
>      (ref:  http://effbot.org/librarybook/fileinput.htm)
>
> import fileinput, sys
>
> for line in fileinput.input(inplace=1):
>     # /convert Windows/DOS text files to Unix files/
>     if line[-2:] == "\r\n":
>         line = line[:-2] + "\n"
>     sys.stdout.write(line)
>
> The inplace argument tells it to create a new file with the same name as
> the original (doing all the necessary nonsense with using a scratch
> file, and renaming/deleting) for each file processed.  Stdout is pointed
> to that new version of the file.  Notice that you have to explicitly
> write everything you want to wind up in the file -- if a given line is
> to remain unchanged, you just write "line" directly.
>
> If you're new to Python, I do not recommend trying to do open/seek to
> update a text file in place, especially if you're in DOS.  There are
> lots of traps.  the inplace method of fileinput avoids these by
> implicitly creating temp files and handling the details for you, which
> probably works great if you're dealing with text, in order.
>
> DaveA

I wonder if inline creates an empty file and then the text from the
processed file gets written to it. If that's what is going on then
it's perfect solution. It will eliminate all the tell() and seek() and
overwriting a shorter line with a longer one.  I'll try it over the
weekend. thanks
-- 
http://mail.python.org/mailman/listinfo/python-list

problem with interface of operator.itemgetter

2009-08-13 Thread dou dou

I have a function to do some thing like LEFT JOIN in SQL, the function use
the itemgetter to get the "ON" and "SELECT" parameters of the two table(list
of list), the problem is that itemgetter may return a value or a tuple of
values, because of the inconsistent return type of itemgetter, I have to do
2^3 IF check,
the function like this:

def left_join(table1, on_index1, table2, on_index2, getter1, getter2):
"""do thing like:
SELECT on1(table1), g1(table1), g2(table2) FROM table1
LEFT JOIN table2
ON on1(table1) == on2(table2)
"""
on1 = itemgetter(*on_index1)
on2 = itemgetter(*on_index2)
g1 = itemgetter(*getter1)
g2 = itemgetter(*getter2)

d2 = {}
d2 = dict((on2(r2), r2) for r2 in table2)

#if itemgetter always return tuple, below could simple as one line
#return [ list(on1(r1) + g1(r1) + g2(d2.get(on1(r1 for r1 in table1
]

len_on = len(on_index1)
len_g1 = len(getter1)
len_g2 = len(getter2)

if len_on == 1:
if len_g1 == 1 and len_g2 == 1:
return [ [on1(r1), g1(r1), g2(d2.get(on1(r1)))] for r1 in table1
]
elif len_g1 == 1 and len_g2 > 1:
return [ list((on1(r1),g1(r1))+g2(d2.get(on1(r1 for r1 in
table1 ]
elif len_g1 > 1 and len_g2 == 1:
return [ list((on1(r1),)+g1(r1)+(g2(d2.get(on1(r1))),))  for r1
in table1 ]
else: #len_g1 > 1 and len_g2 > 1:
return [ list((on1(r1),)+g1(r1)+g2(d2.get(on1(r1 for r1 in
table1 ]
else: # len_on > 1
if len_g1 == 1 and len_g2 == 1:
return [ list(on1(r1))+[g1(r1),g2(d2.get(on1(r1)))] for r1 in
table1 ]
elif len_g1 == 1 and len_g2 > 1:
return [ list(on1(r1)+(g1(r1),)+g2(d2.get(on1(r1 for r1 in
table1 ]
elif len_g1 > 1 and len_g2 == 1:
return [ list(on1(r1)+g1(r1)+(g2(d2.get(on1(r1))),))  for r1 in
table1 ]
else: #len_g1 > 1 and len_g2 > 1:
return [ list(on1(r1)+g1(r1)+g2(d2.get(on1(r1 for r1 in
table1 ]

so is there a way to force itemgetter to return tuple even when
itemgetter(only_have_one_argument)? or some other function to do this?

Thanks.
-- 
http://mail.python.org/mailman/listinfo/python-list

Re: Delegate attribute requests to object

2009-08-13 Thread Gabriel Genellina

En Thu, 13 Aug 2009 12:50:47 -0300, Evan Kroske   
escribió:


I'm trying to use the decorator pattern in a program I'm developing. I  
want

to create a decorator object that works like the object it's decorating
except for a few functions. However, I'd rather not hard-code all the
identical functionality from the decorated object into the decorator  
object.
Is there a way I can intercept all the attribute and function requests  
for

the decorator and delegate them to the decorated object?


You may search the list archives for references to "proxy" and  
"delegation". The term "decorator" has a very specific meaning in Python  
(as a syntax construct), don't use it in the search.



Is it possible (without inheritance)?


Yes, using delegation. See below.

En Thu, 13 Aug 2009 15:29:04 -0300, Rami Chowdhury  
 escribió:


Oops, my apologies, it's the __getattribute__ method you want to call on  
self.decorated (because __getattr__ won't be there unless you define it  
specifically)

So it should go:

def __getattr__(self, request):
return self.decorated.__getattribute__(request)


__getattribute__ doesn't exist on old-style classes either. Also, note  
that very rarely one has to *call* __special__ methods; the code should  
read:


def __getattr__(self, request):
return getattr(self.decorated, request)

but that works *only* for old-style classes, as discussed here [1]. [3] is  
another approach for new-style classes (maybe not production-ready yet).  
And this recipe [2] shows how to make the decorated object keep calling  
methods on the decorator itself.


[1] http://code.activestate.com/recipes/252151/
[2] http://code.activestate.com/recipes/519639/
[3] http://code.activestate.com/recipes/496741/

--
Gabriel Genellina

--
http://mail.python.org/mailman/listinfo/python-list

Re: fileinput

On Aug 13, 1:20 am, "Gabriel Genellina" 
wrote:
> En Wed, 12 Aug 2009 01:27:47 -0300, naaman  escribió:
>
> > I'm writing my first Python script and
> > I want to use fileinput to open a file in r+ mode.
> > Tried fileinput.input(sys.argv[1:],"r+") but that didn't work.
> > ANy ideas?
>
> Don't use fileinput, it can't handle r+, only sequencial access.
> Even if you could use it, the documentation says [1]:
> fileinput.input([files[, inplace[, backup[, mode[, openhook])
>
> "r+" corresponds to the `inplace` parameter (behaving like inplace=True)  
> instead of `mode`. You could write fileinput.input(sys.argv[1:],  
> mode="r+") instead - but again from the docs: "mode... must be one of 'r',  
> 'rU', 'U' and 'rb'"
>
> > Need to find and overwrite a line in a file several times.
> > I can do it using open and seek() etc. but was wondering if I can use
> > fileinput.
>
> open+seek is the way to do that (assuming you don't alter the line length)
>
> [1]http://docs.python.org/library/fileinput.html#fileinput.input
>
> --
> Gabriel Genellina

unfortunately, I am overwriting shorter with longer
-- 
http://mail.python.org/mailman/listinfo/python-list

Re: fileinput