Re: Help replacing os.system call with subprocess call
David Pratt wrote:
> Hi. I am trying to replace a system call with a subprocess call. I have
> tried subprocess.Popen and subprocess.call with but have not been
> successful. The command line would be:
>
> svnadmin dump /my/repository > svndump.db
>
> This is what I am using currently:
>
> os.system('svnadmin dump %s > %s' % (svn_dir,
> os.path.join(backup_dir, 'svndump.db')))
>
> Many thanks.
Try this:
import os.path
import subprocess
p = subprocess.Popen(
['svnadmin', 'dump', svndir],
stdout=subprocess.PIPE,
)
fh = open(os.path.join(backup_dir, 'svndump.db'), 'wb')
while True:
chunk = p.stdout.read(2**20) # 1 MB
if not chunk:
break
fh.write(chunk)
fh.close()
It reads svnadmin's stdout in 1 MB chunks, in case it's large enough
that reading the whole thing into RAM at once would be a bad idea.
No error handling. For one, you might want to add a try...finally to
ensure that fh will get closed. (Or if you have Python 2.5, use a with
statement! :-) ) Also, Popen will raise an OSError if svnadmin can't be
found or something. And this isn't even considering svnadmin erroring out...
svnadmin's stderr will go to your stderr.
I didn't test it, but I'm pretty sure it will work. (I spotted a syntax
error while writing that though.) I don't have much experience with
Popen's stdio objects, so it's possible you'd need to do something like
call p.wait() to wait for it to exit before being able to read its stdout.
It could be slower than the os.system version, since now Python is doing
all of the I/O, instead of your shell, but I doubt that'll be a big problem.
(Also, insert suggestion about using a good VCS. ;-) )
--
--
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Re: Help replacing os.system call with subprocess call
Matt Nordhoff wrote:
> David Pratt wrote:
>> Hi. I am trying to replace a system call with a subprocess call. I have
>> tried subprocess.Popen and subprocess.call with but have not been
>> successful. The command line would be:
>>
>> svnadmin dump /my/repository > svndump.db
>>
>> This is what I am using currently:
>>
>> os.system('svnadmin dump %s > %s' % (svn_dir,
>> os.path.join(backup_dir, 'svndump.db')))
>>
>> Many thanks.
>
> Try this:
>
> import os.path
> import subprocess
>
> p = subprocess.Popen(
> ['svnadmin', 'dump', svndir],
> stdout=subprocess.PIPE,
> )
>
> fh = open(os.path.join(backup_dir, 'svndump.db'), 'wb')
>
> while True:
> chunk = p.stdout.read(2**20) # 1 MB
> if not chunk:
> break
> fh.write(chunk)
>
> fh.close()
>
> It reads svnadmin's stdout in 1 MB chunks, in case it's large enough
> that reading the whole thing into RAM at once would be a bad idea.
>
> No error handling. For one, you might want to add a try...finally to
> ensure that fh will get closed. (Or if you have Python 2.5, use a with
> statement! :-) ) Also, Popen will raise an OSError if svnadmin can't be
> found or something. And this isn't even considering svnadmin erroring out...
>
> svnadmin's stderr will go to your stderr.
>
> I didn't test it, but I'm pretty sure it will work. (I spotted a syntax
> error while writing that though.) I don't have much experience with
> Popen's stdio objects, so it's possible you'd need to do something like
> call p.wait() to wait for it to exit before being able to read its stdout.
>
> It could be slower than the os.system version, since now Python is doing
> all of the I/O, instead of your shell, but I doubt that'll be a big problem.
>
> (Also, insert suggestion about using a good VCS. ;-) )
This might work too:
import os.path
import subprocess
fh = open(os.path.join(backup_dir, 'svndump.db'), 'wb')
p = subprocess.Popen(
['svnadmin', 'dump', svndir],
stdout=fh,
)
# Wait for svnadmin to exit so that fh can be closed
p.wait()
fh.close()
With this, svnadmin's stdout is directly set to the file. Python isn't
being an intermediary reading from stdout and writing it to the file. At
least, that's how I expect it would work.
I didn't test this either. In particular, if Popen doesn't behave how I
expect it should, it might buffer the entirety of stdout in memory or
something, which would be bad if your svn repo is really large...
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--
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ldap
sorry, i'm new with Python. I must do interaction beetween Python and Ldap, and I don't know how do this. Searching on the web I know that exists PythonLdap, but I dont'know if this is best choise or not. Thank's -- http://mail.python.org/mailman/listinfo/python-list
Re: Adherence to PEP 8 for published code (was: ANN: pry unit testing framework)
Thus spake Ben Finney ([EMAIL PROTECTED]): > PEP 8 only has the force that people grant it. Nevertheless, it's a > style guide that's widely accepted in the Python community, and > adhering to it in one's code makes it easier to read for the majority, > because it reduces the needless inconsistencies between different > bodies of code. > > Conversely, deliberately diverging from the widely-accepted style > guide increases the cognitive load on the reader; if that divergence > is not done for a very good reason, one is imposing needless burden on > every reader of the code. This is getting silly. Let's recap. You are upset because I prefer this widely-used method naming convention: object.myName() ... to this one, which was recently adopted as a recommendation in PEP 008 for modules in the standard library: object.my_name() By doing so, you say, I am "imposing needless burden on every reader" of my code... Well, lets look at the facts: First, PEP 8 recommends a naming scheme only for the standard library, and it is not follwed consistently even there. Second, mixedCase is very common both inside and outside the Python project. No-one who codes regularly in Python can be unfamiliar with it, even if they never stray beyond the standard library. Third, this is a minor, recently-introduced convention. Anyone would dislike code that chose not to name classes with an initial capital, or used something other than "self" as the first method parameter. Method naming conventions are far, far fuzzier. The primary issue is simply to clearly distinguish between words in multi-word names - mymethodname would be bad, MYMETHODNAME would be even worse, but my_method_name and myMethodName are both perfectly legible. You are mis-interpreting the intent behind PEP-8 if you think its authors intended to provoke shrill public condemnation of any module that dares to use a long-standing, widely-used alternative method naming scheme. In fact, PEP 8 contains an entire section warning against exactly this kind of inflexible and small-minded application of its recommendations - perhaps you should read it sometime. > > You're also vastly overstating the impact of a minor naming > > convention choice. Calling this a "large black mark" smacks of > > scare-mongering to me. > > When distributing code with the expectation that others use it, it's a > large black mark if it deliberately shun the widely-accepted, > easily-followed coding standards, for the above reasons. > > I don't see why that would be scary. If you find it so, you have my > sympathy. You re-enforce the point you're trying to counter beautifully. Thanks for driving my argument home. Regards, Aldo -- Aldo Cortesi M: +61 419 492 863 P: +61 1300 887 007 W: www.nullcube.com -- http://mail.python.org/mailman/listinfo/python-list
First Python project - comments welcome!
I have started, and made some progress (OK it works, but needs some love) on my first real Python application. http://cvs2.uwc.ac.za/trac/python_tools/browser/podder I would love some feedback on what I have done. In total this has taken me 5 nights to do (I am working on it at night as PHP, not Python, is my day job), so it can probably do with *lots* of improvement. All code is GPL. If anyone on this list is willing/able, please do give me a few pointers, even if it is "This is total crap - RTFM and come back when you are ready" I would really appreciate it! Many thanks, and thank you to this community for helping me through the initial bumps of getting into Python - a great dev tool IMHO! --Paul All Email originating from UWC is covered by disclaimer http://www.uwc.ac.za/portal/public/portal_services/disclaimer.htm -- http://mail.python.org/mailman/listinfo/python-list
csv.DictReader and unicode
This program fin = codecs.open(fname,"r",encoding="UTF-8") eader = csv.DictReader(fin) for values in reader: pass results in: File "run.py", line 23, in process_file for values in reader: File "/usr/local/lib/python2.5/csv.py", line 83, in next row = self.reader.next() UnicodeEncodeError: 'ascii' codec can't encode character u'\xf6' in position 13: ordinal not in range(128) As you can see the exception is thrown in csv.py. How it is possible? The csv.DictReader should not use ascii codec for anything, because the file encoding is UTF-8. Please help. Best, Laszlo -- http://mail.python.org/mailman/listinfo/python-list
Re: ldap
[EMAIL PROTECTED] wrote: > sorry, i'm new with Python. > I must do interaction beetween Python and Ldap, and I don't know how > do this. > Searching on the web I know that exists PythonLdap, but I dont'know if > this is best choise or not. Who cares? Use it, and see if it's good enough for your needs. Then, if not, see if alternatives are better. There seldomly is "the best" if there are several options, because the details and quirks of various solutions might appeal to one and repulse someone else. But nobody is going to know what *you* like best. Diez -- http://mail.python.org/mailman/listinfo/python-list
Re: csv.DictReader and unicode
Peter Otten wrote: > Laszlo Nagy wrote: > > >> This program >> >> fin = codecs.open(fname,"r",encoding="UTF-8") >> eader = csv.DictReader(fin) >> for values in reader: >> pass >> >> results in: >> >> File "run.py", line 23, in process_file >> for values in reader: >> File "/usr/local/lib/python2.5/csv.py", line 83, in next >> row = self.reader.next() >> UnicodeEncodeError: 'ascii' codec can't encode character u'\xf6' in >> position 13: ordinal not in range(128) >> >> As you can see the exception is thrown in csv.py. How it is possible? >> The csv.DictReader should not use ascii codec for anything, because the >> file encoding is UTF-8. >> > > The csv module doesn't support unicode. I understand that csv does not support unicode. I figured out that the exception will not be thrown if I open the file with the built in open() call. > Read the values as byte strings and decode afterwards. > Is there a plan to make csv reader compatible with unicode? Thanks, Laszlo -- http://mail.python.org/mailman/listinfo/python-list
Re: csv.DictReader and unicode
Laszlo Nagy wrote: > This program > > fin = codecs.open(fname,"r",encoding="UTF-8") > eader = csv.DictReader(fin) > for values in reader: > pass > > results in: > > File "run.py", line 23, in process_file > for values in reader: > File "/usr/local/lib/python2.5/csv.py", line 83, in next > row = self.reader.next() > UnicodeEncodeError: 'ascii' codec can't encode character u'\xf6' in > position 13: ordinal not in range(128) > > As you can see the exception is thrown in csv.py. How it is possible? > The csv.DictReader should not use ascii codec for anything, because the > file encoding is UTF-8. The csv module doesn't support unicode. Read the values as byte strings and decode afterwards. Peter -- http://mail.python.org/mailman/listinfo/python-list
Re: csv.DictReader and unicode
Laszlo Nagy napisał(a): > This program > > fin = codecs.open(fname,"r",encoding="UTF-8") > eader = csv.DictReader(fin) > for values in reader: >pass > > results in: > > File "run.py", line 23, in process_file >for values in reader: > File "/usr/local/lib/python2.5/csv.py", line 83, in next >row = self.reader.next() > UnicodeEncodeError: 'ascii' codec can't encode character u'\xf6' in > position 13: ordinal not in range(128) > > As you can see the exception is thrown in csv.py. How it is possible? > The csv.DictReader should not use ascii codec for anything, because the > file encoding is UTF-8. Reader works with byte strings, not unicode objects. -- Jarek Zgoda Skype: jzgoda | GTalk: [EMAIL PROTECTED] | voice: +48228430101 "We read Knuth so you don't have to." (Tim Peters) -- http://mail.python.org/mailman/listinfo/python-list
Re: ldap
On 07/04/2008, [EMAIL PROTECTED] <[EMAIL PROTECTED]> wrote: > sorry, i'm new with Python. > I must do interaction beetween Python and Ldap, and I don't know how > do this. > Searching on the web I know that exists PythonLdap, but I dont'know if > this is best choise or not. > > Thank's > > -- > http://mail.python.org/mailman/listinfo/python-list > I've used python-ldap for writing scripts to interact with LDAP directories quite a few times, check it out here at the cheeseshop: http://pypi.python.org/pypi/python-ldap/ -- http://mail.python.org/mailman/listinfo/python-list
Re: Python Data Utils
On Apr 7, 4:22 pm, Jesse Aldridge <[EMAIL PROTECTED]> wrote:
>
> > changing "( " to "(" and " )" to ")".
>
> Changed.
But then you introduced more.
>
> I attempted to take out everything that could be trivially implemented
> with the standard library.
> This has left me with... 4 functions in S.py. 1 one of them is used
> internally, and the others aren't terribly awesome :\ But I think the
> ones that remain are at least a bit useful :)
If you want to look at stuff that can't be implemented trivially using
str/unicode methods, and is more than a bit useful, google for
mxTextTools.
>
> > A basic string normalisation-before-comparison function would
> > usefully include replacing multiple internal whitespace characters by
> > a single space.
>
> I added this functionality.
Not quite. I said "whitespace", not "space".
The following is the standard Python idiom for removing leading and
trailing whitespace and replacing one or more whitespace characters
with a single space:
def normalise_whitespace(s):
return ' '.join(s.split())
If your data is obtained by web scraping, you may find some people use
'\xA0' aka NBSP to pad out fields. The above code will get rid of
these if s is unicode; if s is str, you need to chuck
a .replace('\xA0', ' ') in there somewhere.
HTH,
John
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Re: A funnily inconsistent behavior of int and float
Mark Dickinson wrote:
> On Apr 6, 1:29 pm, Lie <[EMAIL PROTECTED]> wrote:
>> I've noticed some oddly inconsistent behavior with int and float:
>>
>> Python 2.5.1 (r251:54863, Mar 7 2008, 03:39:23)
>> [GCC 4.1.3 20070929 (prerelease) (Ubuntu 4.1.2-16ubuntu2)] on linux2>>>
>> int('- 345')
>>
>> -345
>>
>> works, but
>>
> float('- 345.083')
>> Traceback (most recent call last):
>> File "", line 1, in
>> ValueError: invalid literal for float(): - 345.083
>
> This is a known issue, that has been fixed for Python 3.0.
> It was decided not to risk breakage by changing this in
> Python 2.x. See:
>
> http://bugs.python.org/issue1779
>
> Mark
This is good but the documentation for
3.0 is missing the syntax documentation
from 2.5
Colin W.
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Re: csv.DictReader and unicode
Laszlo Nagy wrote:
>> Read the values as byte strings and decode afterwards.
Or monkey-patch:
import csv
def make_reader(fin, encoding="UTF-8"):
reader = csv.DictReader(fin)
reader.reader = ([col.decode(encoding) for col in row] for row in
reader.reader)
return reader
fin = open("example.csv")
for record in make_reader(fin):
print record
> Is there a plan to make csv reader compatible with unicode?
I don't know.
Peter
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Re: splitting an XML file on the basis on basis of XML tags
> > What do you mean by "written down to a separate file"? Do you have a specific > format in mind? > sorry, it should be extracted into separate "files". i.e. if i have an XML file containing 10 million records, i need to split the file to 100 files containing 100,000 records each. i hope this is clearer... -- http://mail.python.org/mailman/listinfo/python-list
Re: Python-by-example - new online guide to Python Standard Library
On Apr 3, 8:33 pm, AK <[EMAIL PROTECTED]> wrote:
> AK wrote:
> > Hello,
>
> > I find that I learn easier when I go from specific examples to a more
> > general explanation of function's utility and I made a reference guide
> > that will eventually document all functions, classes and methods in
> > Python's Standard Library. For now, I covered about 20 most important
> > modules. I will be adding more modules and eventually I'll cover
> > everything. Here's my progress so far, let me know if this is useful;
> > I'll be glad to hear comments/suggestions/etc:
>
> >http://www.lightbird.net/py-by-example/
>
> I uploaded an updated site incorporating most of the suggestions I
> received and fixing some errors along the way. I will be adding more
> examples to modules that are already covered and will try to add more
> modules during the following week. Thanks again to all who posted advice
> and comments!
>
I don't know if you've heard of Sphinx, it's being used to generate
the Python 2.6 docs but can also be used standalone. It may have
benefits for a project like yours, particularly with regard to
collaboration and maintainability over the long-term. I've been
playing about with it myself and put together a `very` basic site
using a few of the pages from your site:
The generated html is here:
http://gflanagan.net/site/python/pbe/pbe-sphinx-skeleton-build-0.1.tar.gz
http://gflanagan.net/site/python/pbe/pbe-sphinx-skeleton-build-0.1.zip
And the actual Sphinx 'app':
http://gflanagan.net/site/python/pbe/pbe-sphinx-skeleton-0.1.tar.gz
http://gflanagan.net/site/python/pbe/pbe-sphinx-skeleton-0.1.zip
For which you would need Sphinx (obviously): http://sphinx.pocoo.org/
which depends on docutils: http://docutils.sourceforge.net/
and pygments: http://pygments.org/
There's a make.bat for windows and a MakeFile for unix but the latter
is untested.
I've no time to spend on it further, but you're welcome to what's
there if you've any interest. (I repeat, it's just a proof of concept
- don't expect too much.)
As you might see, I preferred 'doctest' style code rather than the
commented results, but each to their own.
Sphinx uses ReST as its input format - below is what I cooked up for
'restifying' your html, not perfect but a brave attempt!
All the best.
Gerard
--
import textwrap
import re
import os
from BeautifulSoup import BeautifulSoup
def onmatch(m):
return '\nRESULT' + m.group(2)
result = re.compile('(# )?(.*?)',
re.DOTALL | re.MULTILINE)
src = 'c:/workspace/pbe/orig/'
for infile in os.listdir(src):
if not infile.endswith('-module.html'):
continue
title = infile[:-5]
infile = src + infile
outfile = infile[:-4] + 'rst'
out = open(outfile, 'wb')
out.write(title + '\n')
out.write('='*len(title) + '\n\n')
soup = BeautifulSoup(open(infile).read())
for p in soup.findAll('ul'):
print >> out
for line in textwrap.wrap(p.span.contents[0], 79):
print >> out, line.lstrip()
#code = ''.join(comment.sub(onmatch, str(p.pre)))
code = result.sub(onmatch, str(p.pre)).splitlines()[1:-1]
if code:
print >> out
print >> out, '::'
print >> out
for line in code:
line = line.strip()
if line:
leader = ''
if line.startswith('RESULT'):
line = line[len('RESULT'):]
else:
leader += '>>> '
print >> out, leader + line
else:
print >> out
print >> out
out.close()
--
--
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Re: splitting an XML file on the basis on basis of XML tags
pls disregard the above post On Apr 7, 3:13 pm, bijeshn <[EMAIL PROTECTED]> wrote: > > What do you mean by "written down to a separate file"? Do you have a > > specific > > format in mind? > > sorry, it should be extracted into separate " XML files". i.e. if i have an > XML file containing 10 million records, i need to split the file to > 100 XML files containing 100,000 records each. > > i hope this is clearer... -- http://mail.python.org/mailman/listinfo/python-list
Re: First Python project - comments welcome!
Paul Scott wrote: > I have started, and made some progress (OK it works, but needs some > love) on my first real Python application. > > http://cvs2.uwc.ac.za/trac/python_tools/browser/podder > > I would love some feedback on what I have done. In total this has taken > me 5 nights to do (I am working on it at night as PHP, not Python, is my > day job), so it can probably do with *lots* of improvement. All code is > GPL. > > If anyone on this list is willing/able, please do give me a few > pointers, even if it is "This is total crap - RTFM and come back when > you are ready" I would really appreciate it! > > Many thanks, and thank you to this community for helping me through the > initial bumps of getting into Python - a great dev tool IMHO! > The code looks pretty good to someone that doesn't know Gtk graphics. 184: self.wTree2=gtk.glade.XML(globaldir+"podder.glade","serverdialogue") could really do with using os.path.join() if you want to be easily cross-platform. Similarly the other places you use globaldir+"...". At line 321 you loop while True over a Queue.Queue object until the QueueEmpty exception is raised, then break out of the loop. It would be easier to loop while not queue.empty(). I know the docs say that this function is not reliable due to multi-threading semantics, but I doubt it will make your program less responsive. You even put docstrings on your code. WEll done, you are going to enjoy Python. regards Steve -- Steve Holden+1 571 484 6266 +1 800 494 3119 Holden Web LLC http://www.holdenweb.com/ -- http://mail.python.org/mailman/listinfo/python-list
Re: splitting an XML file on the basis on basis of XML tags
the extracted files are to be XML too. ijust need to extract it raw (tags and data just like it is in the parent XML file..) -- http://mail.python.org/mailman/listinfo/python-list
Re: First Python project - comments welcome!
On Mon, 2008-04-07 at 07:05 -0400, Steve Holden wrote: > The code looks pretty good to someone that doesn't know Gtk graphics. > Err, neither do I, so I guess that means its OK? :) > 184: self.wTree2=gtk.glade.XML(globaldir+"podder.glade","serverdialogue") > > could really do with using os.path.join() if you want to be easily > cross-platform. Similarly the other places you use globaldir+"...". > Ah, OK, will take that into cognisance. Main use of the application will be on Ubuntu based laptops in lecture theatres, so I am not overly concerned, however, in the interests of writing better code, and maybe even making it useful to others outside of my project, I will try and fix it up. > At line 321 you loop while True over a Queue.Queue object until the > QueueEmpty exception is raised, then break out of the loop. It would be > easier to loop while not queue.empty(). I know the docs say that this > function is not reliable due to multi-threading semantics, but I doubt > it will make your program less responsive. > That class is not yet even implemented. I put that code in there to do an upload progress bar for the XML-RPC call, but can't yet figure out how to do it properly. That being said, I will take your notes into consideration when I get to it. Thanks! > You even put docstrings on your code. WEll done, you are going to enjoy > Python. Force of habit. :) Thanks very much for your comments, I *really* appreciate it! --Paul All Email originating from UWC is covered by disclaimer http://www.uwc.ac.za/portal/public/portal_services/disclaimer.htm -- http://mail.python.org/mailman/listinfo/python-list
Wxpython. Is it possible to change layout in a running application? Selfmade listbox
Hi, Id like to make my own special listbox.. I want to able (at the push of a button) to add another item to my special listbox... each item is a panel with a label, some buttons and maybe a text control. I've tried adding a new panel object with the stuff i want to the sizer i'm using for my listbox (which is a panel which can contain other panels)... and then run update() and refresh() on everything... But it doesn't work.. i see a panel appearing, but it's just a small square in the corner of my "listbox" panel, and it only works the first time... nothing new appears when I push the button again. Is it at all possible to do this? Has anyone created something similar? Does anyone know what i'm doing wrong? Thanks, Soren -- http://mail.python.org/mailman/listinfo/python-list
Re: while-loops enter the last time after condition is filled?
On 6 avr, 01:53, [EMAIL PROTECTED] wrote: > it seems to me from my results that when i use a while-loop it will > execute once after the condition is met. > > ie the conditions is met the code executes one time more and then > quits. The problem is obviously in your code, but since you failed to post the minimal code exhibiting the problem, we can't help. -- http://mail.python.org/mailman/listinfo/python-list
Calling CVF-Fortran-dll with ctypes and simple structure
Hi all,
I deal with the old problem passing characters from python to a
fortran dll build with CFV6.6c.
I reduced our complex structure to a simple one. Here is the Fortran
code:
SUBROUTINE DEMO2L(s)
C sample for calling CVF6.6c-DLLs from
C vb/vba/python with simple structure
!DEC$ ATTRIBUTES DLLEXPORT::DEMO2L
TYPE rcDEMO
INTEGER a
REAL b
CHARACTER c*9
END TYPE
TYPE(rcDEMO) :: s
C
WRITE(*,*) s.a, s.b, s.c
C sample calculation:
s.a = s.a*10
s.b = s.b**2.3
s.c = 'Sample'
RETURN
END
From VB the calling is very simple:
Declare Sub DEMO2L Lib "release\demo1l.dll" (ByRef k As rcDEMO)
Type rcDEMO
a As Long
b As Single
c As String * 9
End Type
Dim k As rcDEMO
Sub run()
k.a = 2
k.b = 3#
k.c = "Test"
Call DEMO2L(k)
Debug.Print k.a, k.b, k.c
End Sub
and result to: " 2012,5135 Sample"
When I try this from python:
from ctypes import *
class rcDemo(Structure):
_fields_ = [
('a', c_int),
('b', c_float),
('c', c_char_p),
]
mydll = windll.LoadLibrary("release\DEMO1L.DLL")
rc = rcDemo()
rc.a = 2
rc.b = 3.
rc.c = "Test56789"
mydll.DEMO2L(byref(rc))
print rc.a
print rc.b
print ">" + rc.c + "<"
I got " 2 3.00 ♀Å╣" from the debug print in
Fortran and
20
12.513502121
Traceback (most recent call last):
File "run_demo.py", line 21, in ?
print ">" + rc.c + "<"
ValueError: invalid string pointer 0x706D6153
from Python. When passing only the string in a argument list instead
of the structure and considering to pass the length of the string as
2nd argument I am be able to send this characters to the dll and
receive a changed value back.
Have anyone an idea or perhaps a solution ;-) doing this in a
structure?
Thank you!
Michael
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Re: ldap
[EMAIL PROTECTED] wrote: > Searching on the web I know that exists PythonLdap, but I dont'know if > this is best choise or not. http://python-ldap.sf.net is the most complete implementation I know of. (Being the maintainer I might be biased.) It has the caveat of depending on the OpenLDAP client libs and possibly other libs (OpenSSL, cyrus-sasl). So generating a binary build can be heavy work. For which OSs are you developing and which kind of LDAP servers do you want to access? Ciao, Michael. -- http://mail.python.org/mailman/listinfo/python-list
Re: First Python project - comments welcome!
Just a random check. Is __gsignals__ a builtin type? Else it would probably be better not to include the postfix underscores. Though I might be wrong here. Otherwise seems pretty good and well organised. I hate it when people go comment mad, but you've kept them to the places where an explanation is required. Good job :=) -- http://mail.python.org/mailman/listinfo/python-list
Dependency Queue
I'm looking for any information about a certain kind of dynamic data structure. Not knowing if it has some well-known name that I could have Googled, I'll just call it a dependency queue. It's like a priority queue except instead of a strict ordering of items by priority, there is only a topological ordering (like you would have in a directed acyclic graph). To date I've been generating a dependency graph in advance every iteration through my main loop, doing a topsort, and executing the values in order (the values are callable objects--this is a scheduler). However, I'd like a dynamic dependency queue for two reasons: it would simplify things to not have to generate the whole graph in advance, and it could improve performance to run some tasks of the next iteration in the present one (this could potentially make better use of the dual-core and graphics hardware). I'm pretty sure I could hack out this structure on my own, but I'd like to see any prior information if there is any, in case anyone's figured out things like, Is there an easy way to detect cycles on insertion? and so on. Carl Banks -- http://mail.python.org/mailman/listinfo/python-list
Re: @x.setter property implementation
On Apr 6, 6:41 pm, "Daniel Fetchinson" <[EMAIL PROTECTED]> wrote: > > I found out about the new methods on properties, .setter() > > and .deleter(), in python 2.6. Obviously that's a very tempting > > syntax and I don't want to wait for 2.6... > > > It would seem this can be implemented entirely in python code, and I > > have seen hints in this directrion. So before I go and try to invent > > this myself does anyone know if there is an "official" implementation > > of this somewhere that we can steal until we move to 2.6? > > The 2.6 source? Have been grepping all over the place and failed to find it. I found the test module for them, but that doesn't get me very far... -- http://mail.python.org/mailman/listinfo/python-list
Re: splitting an XML file on the basis on basis of XML tags
bijeshn wrote:
> the extracted files are to be XML too. ijust need to extract it raw
> (tags and data just like it is in the parent XML file..)
Ah, so then replace the "print tostring()" line in my example by
ET.ElementTree(element).write("outputfile.xml")
and you're done.
Stefan
--
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Re: Wxpython. Is it possible to change layout in a running application? Selfmade listbox
On Apr 7, 12:50 pm, Soren <[EMAIL PROTECTED]> wrote: > Hi, > > Id like to make my own special listbox.. I want to able (at the push > of a button) to add another item to my special listbox... each item is > a panel with a label, some buttons and maybe a text control. > > I've tried adding a new panel object with the stuff i want to the > sizer i'm using for my listbox (which is a panel which can contain > other panels)... and then run update() and refresh() on everything... > But it doesn't work.. i see a panel appearing, but it's just a small > square in the corner of my "listbox" panel, and it only works the > first time... nothing new appears when I push the button again. > > Is it at all possible to do this? Has anyone created something > similar? Does anyone know what i'm doing wrong? > > Thanks, > Soren Without your code can only really guess, but I'd check that the new panel you are trying to add to the sizer has the listbox as a parent. Iain -- http://mail.python.org/mailman/listinfo/python-list
Re: Wxpython. Is it possible to change layout in a running application? Selfmade listbox
On Apr 7, 6:50 am, Soren <[EMAIL PROTECTED]> wrote: > Hi, > > Id like to make my own special listbox.. I want to able (at the push > of a button) to add another item to my special listbox... each item is > a panel with a label, some buttons and maybe a text control. > > I've tried adding a new panel object with the stuff i want to the > sizer i'm using for my listbox (which is a panel which can contain > other panels)... and then run update() and refresh() on everything... > But it doesn't work.. i see a panel appearing, but it's just a small > square in the corner of my "listbox" panel, and it only works the > first time... nothing new appears when I push the button again. > > Is it at all possible to do this? Has anyone created something > similar? Does anyone know what i'm doing wrong? > > Thanks, > Soren I'm pretty sure it's possible, but as Iain pointed out, it's hard to guess what you're doing wrong without some code. Try making a sample app that demonstrates the issue: http://wiki.wxpython.org/MakingSampleApps Also, you will probably receive more help at the wxPython specific list, found here: http://wxpython.org/maillist.php HTH Mike -- http://mail.python.org/mailman/listinfo/python-list
Re: Is there any way to say ignore case with "in"?
Paul McGuire wrote: > On Apr 6, 8:53 am, "Martin v. Löwis" <[EMAIL PROTECTED]> wrote: I know I could use:- if lower(string1) in lower(string2): but it somehow feels there ought to be an easier (tidier?) way. >> Take, for example, U+017F, LATIN SMALL LETTER LONG S. It's .lower() is >> the same character, as the character is already in lower case. >> It's .upper() is U+0053, LATIN CAPITAL LETTER S. Notice that the LONG >> is gone - there is no upper-case version of a "long s". >> It's .upper().lower() is U+0073, LATIN SMALL LETTER S. >> >> So should case-insensitive matching match the small s with the small >> long s, as they have the same upper-case letter? [ ... ] [i for i in range(65536) if unichr(i).lower().upper() != > ... unichr(i).upper()] > [304, 1012, 8486, 8490, 8491] > > Instead of 15 exceptions to the rule, conversion to upper has only 5 > exceptions. So perhaps comparsion of upper's is, while not foolproof, > less likely to encounter these exceptions? Or at least, simpler to > code explicit tests. I don't know what meaning is carried by all those differences in lower-case glyphs. Converting to upper seems to fold together a lot of variant pi's and rho's which I think would be roughly a good thing. I seem to recall that the tiny iota (ypogegrammeni) has or had grammatical significance. The other effect would be conflating physics' Angstron unit and Kelvin unit signs with ring-a and K. Applicaton programmers beware. Mel. -- http://mail.python.org/mailman/listinfo/python-list
Re: Learning curve for new database program with Python?
On Sun, Apr 6, 2008 at 2:31 AM, John Nagle <[EMAIL PROTECTED]> wrote: > > Basic SQL isn't that hard. Learn CREATE, SELECT, INSERT, > UPDATE, and DELETE syntax. That's enough for most simple > applications. Agreed. What's more, I've found SQL to be the single most transferable skill in IT.. No matter what language and platform you find yourself working on, you'll find an SQL driven relational database somewhere in the mix. Learning SQL isn't a waste of time, I guarantee it. -- Cheers, Simon B. [EMAIL PROTECTED] http://www.brunningonline.net/simon/blog/ -- http://mail.python.org/mailman/listinfo/python-list
Re: Presumably an import is no faster or slower than opening a file?
Paul McGuire <[EMAIL PROTECTED]> wrote:
> On Apr 6, 8:41 am, [EMAIL PROTECTED] wrote:
> > I'm trying to minimise the overheads of a small Python utility, I'm
> > not really too fussed about how fast it is but I would like to
> > minimise its loading effect on the system as it could be called lots
> > of times (and, no, I don't think there's an easy way of keeping it
> > running and using the same copy repeatedly).
> >
> > It needs a configuration file of some sort which I want to keep
> > separate from the code, is there thus anything to choose between a
> > configuration file that I read after:-
> >
> > f = open("configFile", 'r')
> >
> > ... and importing a configuration written as python dictionaries or
> > whatever:-
> >
> > import myConfig
> >
> > --
> > Chris Green
>
> Chris -
>
> The question is less an issue of the file overhead (both must open a
> file, read its contents, and then close it) than what is done with the
> file contents afterwards.
>
> A config file containing .INI-style or whatever content will need to
> be parsed into Python data/objects, and likely use Python code to do
> so. An import will use the Python compiler itself, using optimized
> compiled C code to do the parsing and data/object construction. But I
> think you would only see the distinction in a config file of
> substantial size or complexity. If you think this will make a
> substantial difference in performance, then code up a test case and
> time it.
>
> In general, I'd say that splitting performance hairs to tip a design
> choice one way or another is a misguided premature optimization.
>
I quite agree (about the splitting hairs bit that is), as I said
before I just wanted to check that I wasn't missing anything really
obvious and, thus, that there probably isn't much to choose between
the two approaches. Therefore I'll decide which way to do it on the
basis of 'usability'.
--
Chris Green
--
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Re: A file iteration question/problem
Arnaud Delobelle <[EMAIL PROTECTED]> wrote: > On Apr 6, 4:40 pm, [EMAIL PROTECTED] wrote: > > I want to iterate through the lines of a file in a recursive function > > so I can't use:- > > > > f = open(listfile, 'r') > > for ln in f: > > > > because when the function calls itself it won't see any more lines in > > the file. E.g. more fully I want to do somthing like:- > > > > def recfun(f) > > while True: > > str = readline(f) > > if (str == "") > > break; > > # > > # do various tests > > # > > if : > > recfun(f) > > > > Is there no more elegant way of doing this than that rather clumsy > > "while True" followed by a test? > > > > -- > > Chris Green > > You could use an iterator over the lines of the file: > > def recfun(lines): > for line in lines: > # Do stuff > if condition: > recfun(lines) > > lines = iter(open(filename)) > recfun(lines) > Does that work though? If you iterate through the file with the "for line in lines:" in the first call of recfun(lines) you surely can't do "for line in lines:" and get any sort of sensible result in recursive calls of recfun(lines) can you? -- Chris Green -- http://mail.python.org/mailman/listinfo/python-list
Re: @x.setter property implementation
2008/4/7, Floris Bruynooghe <[EMAIL PROTECTED]>: > > Have been grepping all over the place and failed to find it. I found > the test module for them, but that doesn't get me very far... > I think you should take a look at 'descrobject.c' file in 'Objects' directory. -- Wbr, Andrii Mishkovskyi. He's got a heart of a little child, and he keeps it in a jar on his desk. -- http://mail.python.org/mailman/listinfo/python-list
Re: First Python project - comments welcome!
On 7 avr, 10:03, Paul Scott <[EMAIL PROTECTED]> wrote:
> I have started, and made some progress (OK it works, but needs some
> love) on my first real Python application.
>
> http://cvs2.uwc.ac.za/trac/python_tools/browser/podder
>
> I would love some feedback on what I have done. In total this has taken
> me 5 nights to do (I am working on it at night as PHP, not Python, is my
> day job), so it can probably do with *lots* of improvement. All code is
> GPL.
>
> If anyone on this list is willing/able, please do give me a few
> pointers, even if it is "This is total crap - RTFM and come back when
> you are ready" I would really appreciate it!
Ok, since you asked for it:
22 try:
23 import pygtk
24 #tell pyGTK, if possible, that we want GTKv2
25 pygtk.require("2.0")
26 except:
Don't use bare except clauses, always mention the exception class
you're expecting and let every other exception propagate. Else you may
shadow other unexpected errors (ie: what if the user has a pygtk.py
file in her pythonpath that is unrelated to the expected pygtk
module ? And yes, this kind of thing can and does happen, more often
than you may think).
27 print "You need to install pyGTK or GTKv2 or set your
PYTHONPATH correctly"
stdout is for normal program outputs. Error messages should go to
sys.stderr.
28 print "try: export PYTHONPATH=/usr/local/lib/python2.2/site-
packages/"
29 sys.exit(1)
40 class appgui:
1/ naming convention : should be Appgui or AppGui (cf pep08)
2/ unless you have very compelling reasons to stick with old-style
classes, make your class a newstyle one:
class AppGui(object):
41 def __init__(self):
42 """
43 In this init we are going to display the main recorder
window
44 """
45 global globaldir
46 globaldir="./"
Since this doesn't depend on anything passed to the initializer, and
is initialized with a constant value, this should go to the top-level,
ie:
GLOBAL_DIR = './'
class AppGui(object):
# code here
58 "on_window1_destroy" : (gtk.main_quit)}
This may not do what you think. If what you want is to pass a tuple,
the syntax is:
"on_window1_destroy" : (gtk.main_quit, )
}
notice the trailing ','
59 self.wTree.signal_autoconnect (dic)
60 self.status = STOPPED
61 return
You don't need this return statement.
64 def record_click(self,widget):
(snip)
70 self.player = gst.Pipeline("recorder")
(snip)
87 def pause_click(self,widget):
(snip)
94 if widget.get_active():
95 # print "paused recording..."
96 self.player.set_state(gst.STATE_PAUSED)
This may be a bit of a personnal preference, but I never feel
confortable with attributes added in a method (I mean, else than the
initializer) and accessed in another. Specially when it's a very
important attribute... One reason being that I don't get the 'big
picture' just from browsing the __init__ and the methods names,
another being that now pause_click depends on record_click having been
called before - yet nothing mentions it, nothing documents it, you
have to read the whole code to find about it.
204 try:
205 f=open(globaldir+"lecture.ogg", 'r')
Steve Holden already commented on using os.path.join here, and I
commented about using a top-level constant (GLOBAL_DIR), which will
makes thing more explicit (we know it's a constant, and we will look
for it at the top-level). I'd recommend to also use top-level
symbolic constants for the file names, instead of hardcoding them in
the methods. Same thing for urls etc.
206 b=open(globaldir+"basefile", 'w')
207 encoded = base64.encode(f,b)
208 b.close()
209 except:
210 print "File could not be opened..."
And what you get an exception in the call to base64.encode ? This is
*exactly* why you should *never* use bare except clauses.
(snip more bare except clauses...)
And while we're at it, you forget to close f.
283 if type(currentThread()) != _MainThread:
Since types are singletons, you can use the identity test here:
if type(currentThread()) is not _MainThread:
306 def __init__ (self, parrent, queue, signal,
sendPolicy):
(snip)
309 self.parrent = parrent
Don't you mean 'parent' ?-)
316 v = self.queue.get()
317 if v == None:
identity test again (more idiomatic, and a little bit faster)
318 break
319 threads_enter()
320 l = [v]
'v' is a very poor name, and 'l' is even worse.
431 # Get
stuff
#
432 def isCancelled (self):
433 return self.cancelled
434
435 def isDone
Re: Wxpython. Is it possible to change layout in a running application? Selfmade listbox
On Apr 7, 2:54 pm, Mike Driscoll <[EMAIL PROTECTED]> wrote: > On Apr 7, 6:50 am, Soren <[EMAIL PROTECTED]> wrote: > > Hi, > > > Id like to make my own special listbox.. I want to able (at the push > > of a button) to add another item to my special listbox... each item is > > a panel with a label, some buttons and maybe a text control. > > > I've tried adding a new panel object with the stuff i want to the > > sizer i'm using for my listbox (which is a panel which can contain > > other panels)... and then run update() and refresh() on everything... > > But it doesn't work.. i see a panel appearing, but it's just a small > > square in the corner of my "listbox" panel, and it only works the > > first time... nothing new appears when I push the button again. > > > Is it at all possible to do this? Has anyone created something > > similar? Does anyone know what i'm doing wrong? To remove any doubt, yes this is possible. I guess you forgot to call the Layout method of the sizer (only update or refresh won't help). > Also, you will probably receive more help at the wxPython specific > list, found here: > > http://wxpython.org/maillist.php That is indeed the best list for wxpython related issues. Good luck, Stani -- Phatch - Photo Batch Processor - http://photobatch.stani.be SPE - Python Editor - http://pythonide.stani.be -- http://mail.python.org/mailman/listinfo/python-list
Re: Learning curve for new database program with Python?
On Sun, Apr 6, 2008 at 2:31 AM, John Nagle <[EMAIL PROTECTED]> wrote: > > Basic SQL isn't that hard. Learn CREATE, SELECT, INSERT, > UPDATE, and DELETE syntax. That's enough for most simple > applications. And then learn more advanced SQL: joins, nested selects, pivot tables and stored procedures. You can do a lot of processing "inside" the database which cuts down on data running over the wire. SQL is one of the areas I wish I had mastered (much) earlier in my career --greg. -- http://mail.python.org/mailman/listinfo/python-list
Re: Help replacing os.system call with subprocess call
Hi David and Matt. I appreciate your help which has got me moving
forward again so many thanks for your reply. I have been using
subprocess.Popen a fair bit but this was the first time I had to use
subprocess to capture large file output. The trouble I was having was
with the process would just hang. Chunking was the solution. I guess I
assumed this would be taken care of in the internals.
Overall, I wish subprocess had some better documentation since it is
definitely not a drop in replacement for os.system. In other
circumstances I am using subprocess.call() for simple calls which works
fine.
The speed of this solution is slower than os.system. Would a queue of
some kind be needed to speed this up? Has anyone implemented something
like this? Many thanks.
Regards,
David
Matt Nordhoff wrote:
> David Pratt wrote:
>> Hi. I am trying to replace a system call with a subprocess call. I have
>> tried subprocess.Popen and subprocess.call with but have not been
>> successful. The command line would be:
>>
>> svnadmin dump /my/repository > svndump.db
>>
>> This is what I am using currently:
>>
>> os.system('svnadmin dump %s > %s' % (svn_dir,
>> os.path.join(backup_dir, 'svndump.db')))
>>
>> Many thanks.
>
> Try this:
>
> import os.path
> import subprocess
>
> p = subprocess.Popen(
> ['svnadmin', 'dump', svndir],
> stdout=subprocess.PIPE,
> )
>
> fh = open(os.path.join(backup_dir, 'svndump.db'), 'wb')
>
> while True:
> chunk = p.stdout.read(2**20) # 1 MB
> if not chunk:
> break
> fh.write(chunk)
>
> fh.close()
>
> It reads svnadmin's stdout in 1 MB chunks, in case it's large enough
> that reading the whole thing into RAM at once would be a bad idea.
>
> No error handling. For one, you might want to add a try...finally to
> ensure that fh will get closed. (Or if you have Python 2.5, use a with
> statement! :-) ) Also, Popen will raise an OSError if svnadmin can't be
> found or something. And this isn't even considering svnadmin erroring out...
>
> svnadmin's stderr will go to your stderr.
>
> I didn't test it, but I'm pretty sure it will work. (I spotted a syntax
> error while writing that though.) I don't have much experience with
> Popen's stdio objects, so it's possible you'd need to do something like
> call p.wait() to wait for it to exit before being able to read its stdout.
>
> It could be slower than the os.system version, since now Python is doing
> all of the I/O, instead of your shell, but I doubt that'll be a big problem.
>
> (Also, insert suggestion about using a good VCS. ;-) )
--
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Re: A file iteration question/problem
En Mon, 07 Apr 2008 10:09:13 -0300, <[EMAIL PROTECTED]> escribió: > Arnaud Delobelle <[EMAIL PROTECTED]> wrote: >> def recfun(lines): >> for line in lines: >> # Do stuff >> if condition: >> recfun(lines) >> >> lines = iter(open(filename)) >> recfun(lines) >> > Does that work though? If you iterate through the file with the "for > line in lines:" in the first call of recfun(lines) you surely can't do > "for line in lines:" and get any sort of sensible result in recursive > calls of recfun(lines) can you? Why not? Test and see what happens. -- Gabriel Genellina -- http://mail.python.org/mailman/listinfo/python-list
Re: Help replacing os.system call with subprocess call
>> David Pratt wrote: >>> Hi. I am trying to replace a system call with a subprocess call. I have >>> tried subprocess.Popen and subprocess.call with but have not been >>> successful. The command line would be: >>> >>> svnadmin dump /my/repository > svndump.db En Mon, 07 Apr 2008 10:38:47 -0300, David Pratt <[EMAIL PROTECTED]> escribió: > The speed of this solution is slower than os.system. Would a queue of > some kind be needed to speed this up? Has anyone implemented something > like this? Many thanks. See the last post from Matt Nordhoff, where he calls Popen with stdout=an_open_file. This is the direct translation of ">outfile" in a shell, and faster because it doesn't involve Python processing. -- Gabriel Genellina -- http://mail.python.org/mailman/listinfo/python-list
Re: A file iteration question/problem
[EMAIL PROTECTED] wrote: > Arnaud Delobelle <[EMAIL PROTECTED]> wrote: >> You could use an iterator over the lines of the file: >> >> def recfun(lines): >> for line in lines: >> # Do stuff >> if condition: >> recfun(lines) >> >> lines = iter(open(filename)) >> recfun(lines) > Does that work though? If you iterate through the file with the "for > line in lines:" in the first call of recfun(lines) you surely can't do > "for line in lines:" and get any sort of sensible result in recursive > calls of recfun(lines) can you? Don't speculate, try it. Peter -- http://mail.python.org/mailman/listinfo/python-list
Re: Please test Phatch on Windows (was Re: ANN: Phatch = PHoto bATCH processor and renamer based on PIL)
Hi Steve, Thanks for the confirmation. It is indeed good news. Feel free to send me privately some screenshots. BTW, I just released Phatch 0.1.3 which is the final version for Ubuntu Hardy. Stani On Mar 31, 3:44 am, Steve Holden <[EMAIL PROTECTED]> wrote: > Stani: > > You'll be happy to hear that it appears (after a quick test) to work on > Vista, though I blush to admit I actually have a Python running on that > platform. > > The font selection is much better than in previous versions - although > the names aren't quite the full font names it's pretty easy to tell > which one will be used. > > regards > Steve > > SPE - Stani's Python Editor wrote: > > > > > I have been working the last couple of days purely on bug fixing and > > to port the code ofPhatchfully to Windows as there were many issues. > > This has improved: > > -Phatchcan now create droplets on Windows (win32 extensions > > required) > > - Installed fonts are retrieved from the Windows registry > > - Image file dialogs are now working correctly > > - Missing icons are added (including aphatch.ico) and are now > > displayed in the windows titlebars > > - Image Inspector was missing a panel > > - Preview in Image Inspector now displays correctly > > - (...) > > > Besides thatPhatchnow features for all platforms: > > - fonts can be defined with a nice dropdown autocomplete list > > - drop down lists with convenient values in all actions > > - the action masks now ships with some predefined masks (such as torn > > edges) > > - right click in the actions dialog box to see the source of an action > > - View>Droplet nows shows the name of the action box rendered in the > > logo > > - Dutch translation is 100% complete > > > As such no new features have been added, but the user experience feels > > much more polished now. > > > Please read *carefully* the installation instructions first: > >http://photobatch.wikidot.com/install#toc6 > > > People who have been usingPhatchbefore should clear their font cache > > (if it exists). Simply delete the file: > > C:\Documents and Settings\Username\.phatch\fonts > > > I did thePhatchport on a Windows 2000 machine, so I am curious to > > hear howPhatchworks on Windows XP and Vista. I will fix any bug (as > > far as possible) which is reported quickly in the next couple of days. > > > You can help translatingPhatchhere: > >https://translations.launchpad.net/phatch/trunk/+pots/phatch > > > Thanks in advance, > > > Stani > > > On 18 feb, 15:58, "SPE - Stani's Python Editor" > > <[EMAIL PROTECTED]> wrote: > >> I'm pleased to announce the release ofPhatchwhich is a > >> powerful batch processor and renamer.Phatchexposes a big part of the > >> Python Imaging Library through an user friendly GUI. (It is using > >> python-pyexiv2 to offer more extensive EXIF and IPTC support.)Phatch > >> is not targeted at manipulating individual pictures (such as with > >> Gimp), but repeating the same actions on hundreds or thousands of > >> images. > > >> If you know PIL and have some nice recipes laying around, it is very > >> easy to write plugins asPhatchgenerates the corresponding GUI > >> automagically just like in Django. Any existings PIL scripts can be > >> added very easily. Let me know if you want to contribute or have any > >> questions. > > >> Homepage:http://photobatch.stani.be(freedownload link below) > >> Tutorials:http://photobatch.wikidot.com/tutorials > >> Translations:https://translations.launchpad.net/phatch/trunk/+pots/phatch > >> License: GPLv3 > >> Screenshot:http://photobatch.wikidot.com/local--files/start/Screenshot-Phatch3d.jpg > >> (the perspective and reflection is produced byPhatchitself) > > >> Phatchhas many features, like: > >> - EXIF information inspector with thumbnail > >> - limit jpeg file size when saving > >> - tons of actions organized by tags (including perspective, round > >> corners, shadow, reflection, ...) > >> - console version (Phatchcan now run without a gui on servers) > >> - batch rename and copy files based on exif metadata > >> - data stamping (http://photobatch.wikidot.com) > >> - online documentation wiki (http://photobatch.wikidot.com) > > >> Linux only features: > >> - desktop or panel droplets on which images or folders can be dropped > >> (will be ported to Windows & Mac) > >> - Nautilus and desktop integration (with its own mime type and > >> nautilus extension) > >> - manpage with examples > > >> With python-pyexiv2 the following featues are added: > >> - embedding the original EXIF and IPTC tags in the image > > >> All actions mostly have a separate pil function in their source code, > >> so they could be read as a recipe book for PIL: > >> * Auto Contrast - Maximize image contrast > >> * Background - Put colour under transparent image > >> * Border - Crop or add border to all sides > >> * Brightness - Adjust brightness from black to white > >> * Canvas - Crop the image or enlarge canvas without resizing the image > >> * Colorize - Colorize grayscale image > >> * Common
Re: A funnily inconsistent behavior of int and float
On Apr 7, 6:43 am, "Colin J. Williams" <[EMAIL PROTECTED]> wrote: > This is good but the documentation for > 3.0 is missing the syntax documentation > from 2.5 Is http://docs.python.org/dev/3.0/reference/lexical_analysis.html#integer-literals the documentation that you're looking for? But it seems to me that Lie's original point isn't really about integer *literals* anyway---it's about the behaviour of the built-in int() function when applied to a string. So http://docs.python.org/dev/3.0/library/functions.html#int is probably the appropriate place in the documentation. And I agree that it could be made clearer exactly what strings are acceptable here. Mark -- http://mail.python.org/mailman/listinfo/python-list
Re: Dependency Queue
Carl Banks wrote: > I'm looking for any information about a certain kind of dynamic data > structure. Not knowing if it has some well-known name that I could > have Googled, I'll just call it a dependency queue. It's like a > priority queue except instead of a strict ordering of items by > priority, there is only a topological ordering (like you would have in > a directed acyclic graph). > > To date I've been generating a dependency graph in advance every > iteration through my main loop, doing a topsort, and executing the > values in order (the values are callable objects--this is a > scheduler). > > However, I'd like a dynamic dependency queue for two reasons: it would > simplify things to not have to generate the whole graph in advance, > and it could improve performance to run some tasks of the next > iteration in the present one (this could potentially make better use > of the dual-core and graphics hardware). > > I'm pretty sure I could hack out this structure on my own, but I'd > like to see any prior information if there is any, in case anyone's > figured out things like, Is there an easy way to detect cycles on > insertion? and so on. You might consider flattening your graph to map it onto a heap (see the heapq module). One way to do that might be to assign a different power of two to each node and calculate the priority of each node as the sum of its parent's numbers. That way, a child will always have a higher value (== lower priority) than its parents, so the heap will return it after its parents. If you also want a unique priority instead of the same one for all children of the same set of parents, adding the number of the child itself will give you a (possibly arbitrary) unique priority. This (or a similar approach) may or may not solve your problem, depending on how you determine the dependencies. Stefan -- http://mail.python.org/mailman/listinfo/python-list
Re: Calling CVF-Fortran-dll with ctypes and simple structure
En Mon, 07 Apr 2008 09:19:03 -0300, Michael Schäfer <[EMAIL PROTECTED]>
escribió:
> Hi all,
>
> I deal with the old problem passing characters from python to a
> fortran dll build with CFV6.6c.
> I reduced our complex structure to a simple one. Here is the Fortran
> code:
>
> SUBROUTINE DEMO2L(s)
>
> C sample for calling CVF6.6c-DLLs from
> C vb/vba/python with simple structure
>
> !DEC$ ATTRIBUTES DLLEXPORT::DEMO2L
>
> TYPE rcDEMO
> INTEGER a
> REAL b
> CHARACTER c*9
> END TYPE
>
> TYPE(rcDEMO) :: s
> C
> WRITE(*,*) s.a, s.b, s.c
> C sample calculation:
> s.a = s.a*10
> s.b = s.b**2.3
> s.c = 'Sample'
>
> RETURN
> END
>
> From VB the calling is very simple:
>
> Declare Sub DEMO2L Lib "release\demo1l.dll" (ByRef k As rcDEMO)
>
> Type rcDEMO
> a As Long
> b As Single
> c As String * 9
> End Type
>
> Dim k As rcDEMO
>
> Sub run()
>
> k.a = 2
> k.b = 3#
> k.c = "Test"
>
> Call DEMO2L(k)
>
> Debug.Print k.a, k.b, k.c
>
> End Sub
>
> and result to: " 2012,5135 Sample"
>
> When I try this from python:
>
> from ctypes import *
>
> class rcDemo(Structure):
> _fields_ = [
> ('a', c_int),
> ('b', c_float),
> ('c', c_char_p),
Try with ('c', c_char*9). You may have alignment issues with such odd
size, but in this case it doesnt matter so much as it's the last field in
the struct.
(If both Fortran and VB say "char*9", why did you choose a pointer here?)
--
Gabriel Genellina
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Re: Help replacing os.system call with subprocess call
David Pratt wrote: > Hi David and Matt. I appreciate your help which has got me moving > forward again so many thanks for your reply. I have been using > subprocess.Popen a fair bit but this was the first time I had to use > subprocess to capture large file output. The trouble I was having was > with the process would just hang. Chunking was the solution. I guess I > assumed this would be taken care of in the internals. > > Overall, I wish subprocess had some better documentation since it is > definitely not a drop in replacement for os.system. In other > circumstances I am using subprocess.call() for simple calls which works > fine. > > The speed of this solution is slower than os.system. Would a queue of > some kind be needed to speed this up? Has anyone implemented something > like this? Many thanks. > > Regards, > David Did you see my second message? That should help performance. If not, I'm totally out of my depth and have no idea at all. Sorry. (How much slower? 10%? 200%?) -- -- http://mail.python.org/mailman/listinfo/python-list
Getting a value from a nested dictionary
Hi, My name is Dan and I'm a newb to python (and programming. Please
forgive)
I am trying to get a value from a nested dictionary. I would like to
pass in a parameter from a conf file, then compare it to a value in the
dictionary, and verify that it is a valid value. (The SSL_MODE Portion
of the below listed dictionary)
I have d1{key1: val1,
key2: val_2{key_a: val_a, key_b: val_b},
key3: val_3}
And In comes the value from the conf file key2: val_a
Any Ideas?
Dan C
#!/usr/local/bin/python2.5
# -*- coding: UTF-8 -*-
# File extractconf.py
# The file authn.conf must exist
import os
import sys
import re
CONF_FILE = "authn.conf"
#Use these defaults if none are provided in the .conf file
PARAMS_VALUES = {"INSTANCE_NAME": "",
"CHASE_REFERRALS": False,
"DOMAIN_NAME": "",
"GROUP_CONTAINER": "",
"PASSWORD": "",
"SSL_MODE": {"ssl1": "NO_SSL", "ssl2": "SSL_TRUST_ALL",
"ssl3": "SSL_CERTIFICATE_MODE"},
"USE_GC": False,
"USE_KERBEROS": False,
"USER_CONTAINER": "",
"USER_NAME": "",
"USER_NAME_TYPE": {'unt1': "FULL_SAM", 'unt2':
"PARTIAL_SAM", 'unt3': "FULL_UPN", 'unt4': "PARTIAL_UPN"}}
def extractParams():
thedir = os.getcwd() #Parse the dir and get the file listing
filelist = os.listdir(thedir)
if CONF_FILE in filelist:
thefile = open("authn.conf").readlines()
thefile = [l.strip() for l in thefile] #Strip out the
whitespace
thefile = [l for l in thefile if l.find('=') >= 0] #
Filters out non-conf lines
thefile = [re.split(r"\s*=\s*", l) for l in thefile]
#Use regex and get out spaces
thefile = [(l[0], eval(l[1])) for l in thefile]
#Evaluate the str and bool values
thefile = dict(thefile) #Turn the file into a dictionary
for k in thefile.keys(): #For each entry in the file
if k == 'SSL_MODE': #If the key is equal to the
SSL_MODE key
##THIS IS WHERE I'M STUCK
print PARAMS_VALUES['SSL_MODE']
##else:
## THIS PART IS OK
for k in PARAMS_VALUES.keys(): #Replace values in
default dict with the values from the conf file
PARAMS_VALUES[k] = thefile[k]
else:
sys.exit("File authn.conf must exist")
if __name__ == "__main__":
extractParams()
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Python-URL! - weekly Python news and links (Apr 7)
QOTW: "Describing [Python] as a 'scripting language' is like describing a fully-equipped professional kitchen as 'a left-over warming room'." - Steven D'Aprano "[S]ocial measures are the only thing that *can* properly deal with these issues [in this case, naming conflicts, functionality non-partitioning, ...--naming issues, really]." - Ben Finney Python 2.6a2 and 3.0a4 have been released, two new alpha versions of the next major releases: http://groups.google.com/group/comp.lang.python/browse_thread/thread/6cf534b1163b627/ A long thread: Object-Relational Mappers (ORM), pros and cons: http://groups.google.com/group/comp.lang.python/browse_thread/thread/a9b670f2a2b5be42/ Generator functions with recursive calls: why must a loop be explicit? http://groups.google.com/group/comp.lang.python/browse_thread/thread/8923ccee2062473a/ Since 3.0 will be ready soon, why should anyone new to the language bother to learn the old 2.X? http://groups.google.com/group/comp.lang.python/browse_thread/thread/44ace1486d840678/ Adding methods to a single instance: http://groups.google.com/group/comp.lang.python/browse_thread/thread/ba80ed8bf095b12f/ Teaching Python in high school: http://groups.google.com/group/comp.lang.python/browse_thread/thread/846ca6453d396fe0/ Python-by-example, examples covering all the standard library modules. http://groups.google.com/group/comp.lang.python/browse_thread/thread/d94853f357614b25/ http://www.lightbird.net/py-by-example/ Incorrect usage of the try/finally construct: http://groups.google.com/group/comp.lang.python/browse_thread/thread/ac8d61438c4c00ca/ super() - when to use (and when not to use it): http://groups.google.com/group/comp.lang.python/browse_thread/thread/22a35db06b0e9764/ Testing whether any string from a set is contained within another string: http://groups.google.com/group/comp.lang.python/browse_thread/thread/5261983811a04956/ Everything Python-related you want is probably one or two clicks away in these pages: Python.org's Python Language Website is the traditional center of Pythonia http://www.python.org Notice especially the master FAQ http://www.python.org/doc/FAQ.html PythonWare complements the digest you're reading with the marvelous daily python url http://www.pythonware.com/daily Mygale is a news-gathering webcrawler that specializes in (new) World-Wide Web articles related to Python. http://www.awaretek.com/nowak/mygale.html While cosmetically similar, Mygale and the Daily Python-URL are utterly different in their technologies and generally in their results. Just beginning with Python? This page is a great place to start: http://wiki.python.org/moin/BeginnersGuide/Programmers The Python Papers aims to publish "the efforts of Python enthusiats": http://pythonpapers.org/ The Python Magazine is a technical monthly devoted to Python: http://pythonmagazine.com Readers have recommended the "Planet" sites: http://planetpython.org http://planet.python.org comp.lang.python.announce announces new Python software. Be sure to scan this newsgroup weekly. http://groups.google.com/groups?oi=djq&as_ugroup=comp.lang.python.announce Python411 indexes "podcasts ... to help people learn Python ..." Updates appear more-than-weekly: http://www.awaretek.com/python/index.html Steve Bethard continues the marvelous tradition early borne by Andrew Kuchling, Michael Hudson, Brett Cannon, Tony Meyer, and Tim Lesher of intelligently summarizing action on the python-dev mailing list once every other week. http://www.python.org/dev/summary/ The Python Package Index catalogues packages. http://www.python.org/pypi/ The somewhat older Vaults of Parnassus ambitiously collects references to all sorts of Python resources. http://www.vex.net/~x/parnassus/ Much of Python's real work takes place on Special-Interest Group mailing lists http://www.python.org/sigs/ Python Success Stories--from air-traffic control to on-line match-making--can inspire you or decision-makers to whom you're subject with a vision of what the language makes practical. http://www.pythonology.com/success The Python Software Foundation (PSF) has replaced the Python Consortium as an independent nexus of activity. It has official responsibility for Python's development and maintenance. http://www.python.org/psf/ Among the ways you can support PSF is with a donation. http://www.python.org/psf/donate.html Kurt B. Kaiser publishes a weekly report on faults and patc
Orphaned child processes
I'm using the Python processing module. I've just run into a problem though. Actually, it's a more general problem that isn't specific to this module, but to the handling of Unix (Linux processes) in general. Suppose for instance that for some reason or another, after forking several child processes, the main process terminates or gets killed (or segfaults or whatever) and the child processes are orphaned. Is there any way to automatically arrange things so that they auto- terminate or, in other words, is there a way to make the child processes terminate when the parent terminates? Thank you. -- http://mail.python.org/mailman/listinfo/python-list
Re: Adherence to PEP 8 for published code
Aldo Cortesi <[EMAIL PROTECTED]> writes: > This is getting silly. Agreed. > Let's recap. You are upset Not at all. -- \ "We spend the first twelve months of our children's lives | `\ teaching them to walk and talk and the next twelve years | _o__)telling them to sit down and shut up." -- Phyllis Diller | Ben Finney -- http://mail.python.org/mailman/listinfo/python-list
Re: Welcome to the "Python-list" mailing list
This is my first post and I'm new to Python. How would someone go about adding keywords to Python? It would be great to add support for Esperanto keywords in the language instead of English being the only option. thx -- http://mail.python.org/mailman/listinfo/python-list
Re: Welcome to the "Python-list" mailing list
Ronn Ross wrote: > This is my first post and I'm new to Python. How would someone go about > adding keywords to Python? It would be great to add support for > Esperanto keywords in the language instead of English being the only > option. > Unfortunately the resulting language would no longer be Python. You need to consider software portability: Python has been very conservative about declaring words to be "keywords" in the language, though clearly words like "def" and "class" must necessarily be part of the syntax. When you start to replace the keywords, though, your programs are no longer runnable on all Python installations, and simple transliteration fails because sometimes a keyword in one (natural) language will conflict with a programmer's choice of name(s) in another. So it's a superficially attractive idea with some really bad downside consequences. regards Steve -- Steve Holden+1 571 484 6266 +1 800 494 3119 Holden Web LLC http://www.holdenweb.com/ -- http://mail.python.org/mailman/listinfo/python-list
Re: Python Data Utils
> But then you introduced more.
oops. old habits...
> mxTextTools.
This looks cool, so does the associated book - "Text Processing in
Python". I'll look into them.
> def normalise_whitespace(s):
> return ' '.join(s.split())
Ok, fixed.
> a.replace('\xA0', ' ') in there somewhere.
Added.
Thanks again.
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Re: Help replacing os.system call with subprocess call
Hi Matt. Many thanks. Sorry I had not seen your second post. I'll give this a try and time the completion to compare the differences and post back later today to show os.system, buffered imput and using a file directly for stdout. Regards, David Matt Nordhoff wrote: > David Pratt wrote: >> Hi David and Matt. I appreciate your help which has got me moving >> forward again so many thanks for your reply. I have been using >> subprocess.Popen a fair bit but this was the first time I had to use >> subprocess to capture large file output. The trouble I was having was >> with the process would just hang. Chunking was the solution. I guess I >> assumed this would be taken care of in the internals. >> >> Overall, I wish subprocess had some better documentation since it is >> definitely not a drop in replacement for os.system. In other >> circumstances I am using subprocess.call() for simple calls which works >> fine. >> >> The speed of this solution is slower than os.system. Would a queue of >> some kind be needed to speed this up? Has anyone implemented something >> like this? Many thanks. >> >> Regards, >> David > > Did you see my second message? That should help performance. If not, I'm > totally out of my depth and have no idea at all. Sorry. > > (How much slower? 10%? 200%?) -- http://mail.python.org/mailman/listinfo/python-list
WORLD TOURSIM WORLD TRAVEL WORLD PACKAGE
Freee... Freee Fr http://sai-tourism-package.blogspot.com/ -- http://mail.python.org/mailman/listinfo/python-list
Mathematical Python Library
I'm looking for a library which can do mathematical stuff like solving equations. Or calculation the nulls of a function and so on. Does anyone know one? Thanks in advance! -- http://mail.python.org/mailman/listinfo/python-list
Re: Learning curve for new database program with Python?
On 2008-04-07 15:30, Greg Lindstrom wrote: > On Sun, Apr 6, 2008 at 2:31 AM, John Nagle <[EMAIL PROTECTED]> wrote: >> Basic SQL isn't that hard. Learn CREATE, SELECT, INSERT, >> UPDATE, and DELETE syntax. That's enough for most simple >> applications. > > And then learn more advanced SQL: joins, nested selects, pivot tables and > stored procedures. You can do a lot of processing "inside" the database > which cuts down on data running over the wire. > > SQL is one of the areas I wish I had mastered (much) earlier in my career Fully agree :-) Interesting comments in a time where everyone seems to be obsessed with ORMs. -- Marc-Andre Lemburg eGenix.com Professional Python Services directly from the Source (#1, Apr 07 2008) >>> Python/Zope Consulting and Support ...http://www.egenix.com/ >>> mxODBC.Zope.Database.Adapter ... http://zope.egenix.com/ >>> mxODBC, mxDateTime, mxTextTools ...http://python.egenix.com/ Try mxODBC.Zope.DA for Windows,Linux,Solaris,MacOSX for free ! eGenix.com Software, Skills and Services GmbH Pastor-Loeh-Str.48 D-40764 Langenfeld, Germany. CEO Dipl.-Math. Marc-Andre Lemburg Registered at Amtsgericht Duesseldorf: HRB 46611 -- http://mail.python.org/mailman/listinfo/python-list
Re: Mathematical Python Library
The closest thing so far is probably going to be a combination of the numpy, scipy, and sympy libraries. The latter is the one with the most functionality for solving equations algebraically, but is also the least mature package at the moment. The first two also provide the basic tools for calculating the nulls of a function (for instance) as numerical approximations, provided you are able to write small scripts to use those tools. -Rob On Mon, Apr 7, 2008 at 12:05 PM, mc <[EMAIL PROTECTED]> wrote: > I'm looking for a library which can do mathematical stuff like > solving equations. Or calculation the nulls of a function and so on. > Does anyone know one? > > Thanks in advance! > -- > http://mail.python.org/mailman/listinfo/python-list > -- Robert H. Clewley, Ph. D. Assistant Professor Department of Mathematics and Statistics Georgia State University 720 COE, 30 Pryor St Atlanta, GA 30303, USA tel: 404-413-6420 fax: 404-651-2246 http://www.mathstat.gsu.edu/~matrhc http://brainsbehavior.gsu.edu/ -- http://mail.python.org/mailman/listinfo/python-list
reading dictionary's (key,value) from file
Folks,
Is it possible to read hash values from txt file.
I have script which sets options. Hash table has key set to option,
and values are option values.
Way we have it, we set options in a different file (*.txt), and we
read from that file.
Is there easy way for just reading file and setting options instead of
parsing it.
so this is what my option files look like:
1opt.txt
{ '-cc': '12',
'-I': r'/my/path/work/'}
2opt.txt
{ '-I': r/my/path/work2/'}
so my scipt how has dictionary
options = { '-cc' :'12'
'-I': r'/my/path/work/:/my/path/work2/'}
I am trying to avoid parsing
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Re: reading dictionary's (key,value) from file
[EMAIL PROTECTED] wrote:
> Folks,
> Is it possible to read hash values from txt file.
> I have script which sets options. Hash table has key set to option,
> and values are option values.
>
> Way we have it, we set options in a different file (*.txt), and we
> read from that file.
> Is there easy way for just reading file and setting options instead of
> parsing it.
>
> so this is what my option files look like:
>
> 1opt.txt
> { '-cc': '12',
> '-I': r'/my/path/work/'}
>
> 2opt.txt
> { '-I': r/my/path/work2/'}
>
> so my scipt how has dictionary
> options = { '-cc' :'12'
> '-I': r'/my/path/work/:/my/path/work2/'}
>
> I am trying to avoid parsing
Use a well-known config-file-format such as the module ConfigParser
supports.
Diez
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Re: reading dictionary's (key,value) from file
[EMAIL PROTECTED] wrote:
> Folks,
> Is it possible to read hash values from txt file.
> I have script which sets options. Hash table has key set to option,
> and values are option values.
>
> Way we have it, we set options in a different file (*.txt), and we
> read from that file.
> Is there easy way for just reading file and setting options instead of
> parsing it.
>
> so this is what my option files look like:
>
> 1opt.txt
> { '-cc': '12',
> '-I': r'/my/path/work/'}
>
> 2opt.txt
> { '-I': r/my/path/work2/'}
>
> so my scipt how has dictionary
> options = { '-cc' :'12'
> '-I': r'/my/path/work/:/my/path/work2/'}
>
> I am trying to avoid parsing
>
For this particular case, you can use the optparse module:
http://docs.python.org/lib/module-optparse.html
Since you're obviously running commands with different set of options, I
suggest you listen to Diez.
Cheers,
RB
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Re: reading dictionary's (key,value) from file
[EMAIL PROTECTED] wrote:
> so this is what my option files look like:
>
> 1opt.txt
> { '-cc': '12',
> '-I': r'/my/path/work/'}
You can turn these strings read from text files into actual dictionaries
using eval:
>>> d = eval("{ '-cc': '12', '-I': r'/my/path/work/'}")
>>> d
{'-I': '/my/path/work/', '-cc': '12'}
>>> type(d)
Note that eval will happily execute all sorts of arbitrary code, so this is
not a good solution if you don't fully trust your option file creators.
It's also a bit clunky compared to simply importing. Since you already have
dictionary-literal syntax in your text file, why not add a
left-hand-operator and make it a module instead? For example:
# opt1.py
d = { '-cc': '12',
'-I': r'/my/path/work/'}
# main.py
from opt1 import d
--
Jeffrey
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pylirc question: clearing the queue
Hi all, Is there a way in the pylirc module to either (a) get it to stop listening for a period of time, or (b) clear the queue of any stored up commands? I have a script that starts mplayer, and I use my remote while I'm running mplayer. The shell script waits (subrpocess.Popen.wait()) for the mplayer process to complete, but then it always runs through all the keypresses I've been sending mplayer. So i would like it to either stop listening until I give it a certain command, or to simply clear the queue (I could tell it to that after I return from wait()). Any ideas? Thanks, Jesse -- http://mail.python.org/mailman/listinfo/python-list
Re: First Python project - comments welcome!
On Apr 7, 3:03 pm, Paul Scott <[EMAIL PROTECTED]> wrote: > I have started, and made some progress (OK it works, but needs some > love) on my first real Python application. > > http://cvs2.uwc.ac.za/trac/python_tools/browser/podder > > I would love some feedback on what I have done. In total this has taken > me 5 nights to do (I am working on it at night as PHP, not Python, is my > day job), so it can probably do with *lots* of improvement. All code is > GPL. > > If anyone on this list is willing/able, please do give me a few > pointers, even if it is "This is total crap - RTFM and come back when > you are ready" I would really appreciate it! > > Many thanks, and thank you to this community for helping me through the > initial bumps of getting into Python - a great dev tool IMHO! > > --Paul > > All Email originating from UWC is covered by > disclaimerhttp://www.uwc.ac.za/portal/public/portal_services/disclaimer.htm I don't know if it was just me, but I can't just scan through your code briefly to know what it is about (as is with any non-trivial codes), only after looking through the website's Roadmap I realized it's something to do with audio and recording. Perhaps you should add a short module-level docstring that explains in a brief what the code is about, somewhat like an abstract. And second, it's just my personal preference, but I usually like to separate between GUI codes (codes that handle GUI events) and working code (the real worker). It's just so that if one day you want to revamp the GUI (e.g. unify the play and pause button into a single morphing button), you could do it easily without touching the working code or if you want to call pause() from somewhere else other than GUI (from an error handler?), you don't call it by pause_click() while no clicking is done. It's also helpful if someday you want to make a command-line version of the program (for the same reason, so we don't call play_click() while what we're doing is typing some commands) or change the GUI engine. It's also helpful if we want to do something fancy that is GUI-related, like clicking the play button will keep it depressed until we click the stop button (like that ol' tape recorder) -- http://mail.python.org/mailman/listinfo/python-list
Re: Dependency Queue
"Carl Banks" <[EMAIL PROTECTED]> wrote in message news:[EMAIL PROTECTED] | I'm looking for any information about a certain kind of dynamic data | structure. Not knowing if it has some well-known name that I could | have Googled, I'll just call it a dependency queue. It's like a | priority queue except instead of a strict ordering of items by | priority, there is only a topological ordering (like you would have in | a directed acyclic graph). | | To date I've been generating a dependency graph in advance every | iteration through my main loop, doing a topsort, and executing the | values in order (the values are callable objects--this is a | scheduler). | | However, I'd like a dynamic dependency queue for two reasons: it would | simplify things to not have to generate the whole graph in advance, | and it could improve performance to run some tasks of the next | iteration in the present one (this could potentially make better use | of the dual-core and graphics hardware). | | I'm pretty sure I could hack out this structure on my own, but I'd | like to see any prior information if there is any, in case anyone's | figured out things like, Is there an easy way to detect cycles on | insertion? and so on. Perhaps what you want is a dynamic DAG (directed acyclic graph) with ordered labels. At any time, only the set of sources are eligible for execution, so there is no reason to flatten the whole thing. I suspect insertion with cycle detection would be easier, but I don't remember actually seeing an algorithm. tjr -- http://mail.python.org/mailman/listinfo/python-list
Re: First Python project - comments welcome!
On Mon, 2008-04-07 at 09:56 -0700, Lie wrote: > I don't know if it was just me, but I can't just scan through your > code briefly to know what it is about (as is with any non-trivial > codes), only after looking through the website's Roadmap I realized > it's something to do with audio and recording. Perhaps you should add > a short module-level docstring that explains in a brief what the code > is about, somewhat like an abstract. > Sure, will add that. It is a simple GUI based audio (and later video) recorder that a user can record a audio stream from line in (mic) and create an ogg vorbis file from it. It then allows the user to upload the ogg file to a Chisimba (PHP5 - my day job) based server to be consumed automagically as a podcast. The file is tagged and converted to MP3 server side and added to the Chisimba podcast module. It is really for use in lecture halls so that lecturers can upload their audio files as podcasts for the students to listen to almost immediately afterwards. > And second, it's just my personal preference, but I usually like to > separate between GUI codes (codes that handle GUI events) and working > code (the real worker). Couldn't agree more! MVC architecture is how I do all of my code. Unfortunately, this was my first stab at 1. Python 2. GUI applications 3. Audio apps so I will need some more help in doing that (i.e. ramping up my skills or getting someone that knows what they are doing onto the project to help out). Thanks for the feedback though, I will improve in time... :) --Paul All Email originating from UWC is covered by disclaimer http://www.uwc.ac.za/portal/public/portal_services/disclaimer.htm -- http://mail.python.org/mailman/listinfo/python-list
Re: Learning curve for new database program with Python?
On 7 avr, 07:34, CM <[EMAIL PROTECTED]> wrote: > On Apr 5, 11:50 am, Jetus <[EMAIL PROTECTED]> wrote: > > > I have a need for a database program. I downloaded the db2 from ibm, > > and reviewed some of the documentation. > > > My question is, what is the easiest program for me to try to learn. I > > will be creating a database of about 25,000 records, it will be > > relational. I am a beginner Python programmer, and need a database > > solution that is easy to grasp. I played with sql, > > and found that very difficult, if not overly cumbersome. > > > A database that could work with Django would be very interesting to > > look at as well.. > > > Any suggestions out there? > > From the good people at Django: > > "If you want to use Django with a database, which is probably the > case, you'll also need a database engine. PostgreSQL is recommended, > because we're PostgreSQL fans, and MySQL, SQLite 3, and Oracle are > also supported." > > And if you want to make it a relational database, Err... I may totally misunderstand you here, but I've the strong impression that you missed the fact that the database systems mentionned above are all (so-called) relational dabatases. -- http://mail.python.org/mailman/listinfo/python-list
Re: Learning curve for new database program with Python?
On 5 avr, 17:50, Jetus <[EMAIL PROTECTED]> wrote: > I have a need for a database program. I downloaded the db2 from ibm, > and reviewed some of the documentation. > > My question is, what is the easiest program for me to try to learn. I > will be creating a database of about 25,000 records, it will be > relational. I am a beginner Python programmer, and need a database > solution that is easy to grasp. I played with sql, > and found that very difficult, if not overly cumbersome. The point is that so far, "relational database" really means "SQL database". And believe me, trying to get away with a non-SQL database only to avoid learning SQL is probably the worst possible move for both your program and yourself. > A database that could work with Django would be very interesting to > look at as well.. The databases that the ORM part of Django can connect to are all SQL databases. > Any suggestions out there? I can only second / third etc what everyone already told you : learn SQL. And not only SQL, but also the theory that it builds upon (the 'relational model'), and the good practices wrt/ relational database design. There's no shortage of good quality freely available documentation on these topics, and you'll find help on quite a couple of newsgroups / forums / whatever. I'd strongly recommand you start without Django's ORM first, so you get a chance to learn how it really works undercover. Else you might end up doing things in a very inefficient way. -- http://mail.python.org/mailman/listinfo/python-list
Re: Welcome to the "Python-list" mailing list
"Ronn Ross" <[EMAIL PROTECTED]> wrote in message news:[EMAIL PROTECTED] | This is my first post and I'm new to Python. How would someone go about | adding keywords to Python? It would be great to add support for Esperanto | keywords in the language instead of English being the only option. If you want other-language keywords, you should either use a translator processor or an editor that will do keyword substitution. I do not know of such but I would not be surprised if there is one. I suspect this sort of thing will more likely happen with Python 3, which will allow unicode keywords. PS. Subject lines should reflect the subject of the post. -- http://mail.python.org/mailman/listinfo/python-list
Tips for load balancing multiple Python apps on dual/quad core processors?
I'm looking for tips on how to load balance running multiple Python applications in multi-CPU environments. My understanding is that Python applications and their threads are limited to a specific CPU. Background: I have a Python utility that processes email messages. I suspect there's a lot of idle time while this utility waits on a remote email server. I would like to run as many simultaneous copies of this utility as possible without overwhelming the server these utilities are running on. My thought is that I should write a dispatcher that monitors CPU load and launches/cancels multiple instances of my utility with specific job queues to process. Is there a cross-platform way to monitor CPU load? Is there a pre-existing Python module I should be looking at for building (subclassing) my dispatcher? Thanks! Malcolm -- http://mail.python.org/mailman/listinfo/python-list
Re: Adding Images To MySQL
in line...
On 4/5/08, Gabriel Genellina <[EMAIL PROTECTED]> wrote:
>
> En Sat, 05 Apr 2008 11:32:00 -0300, Victor Subervi
> <[EMAIL PROTECTED]> escribió:
>
> >> * *- You say Content-Type: image/jpeg but you emit HTML code. You're
> >> lucky
> > if you see any
> >
> >> * *text at all.
> >
> > Well, I tried Content-Type: text/html and that threw an HTTP 500 Error.
>
> If your script raised any exception, that's the expected code. (500 =
> internal error = your code has errors). But it's not very useful for
> debugging; using cgitb or wrapping the code in try/except as has already
> been suggested, lets you see the exception and traceback.
Yes, and I have employed your suggestion of cgtib, and I sent you personally
under separate cover the errors, since I forgot to include them in this
post.
>> * *- HTTP 200 is not an error, it means the request was successful.
> >
> > When it doesn´t execute the code, how can it be called successful? If it
> > doesn´t execute the code, how can you say it´s not an error? What is it,
> > then?
>
> Well, your web server thinks all went ok... BTW, you did't provide details
> about it, I *guess* you're using CGI because of the print "Content-Type"
> line.
Yes, that is correct...
>> * *- As a general advice, try to isolate the problems. Test the database
> > stuff alone, in a local
> >> * *application. Test the cgi script alone, without database
> interaction.
> > Test the database stuff in
> >> * *the web server (better if you have a shell account). Merge all and
> >> test
> > again.
> >
> > Very good advice. Please help me understand how to do that.
> >
> > This is what I have done. I have tried these:
> >
> > sql = "'insert into products (" + col_names + ") values (" + val + ")',
> > (" +
> > col_names + ")"
> >
> > cursor.execute(sql)
> >
> > and
> >
> > sql = "'insert into products (" + col_names + ") values (" + val + ")'"
> >
> > cursor.execute(sql, (col_names,))
> >
> > Neither work.
>
> You got a syntax error, I guess. What's that ' at the start?
> I'll try to explain it from the ground up. This would be a valid SQL
> statement::
>
> insert into PRODUCTS (PRODID, NAME, DESCRIPTION)
> values (123, 'Easter egg 80g', 'A longer description');
>
> In Python, you need the SQL text inside a string::
>
> sql = "insert into PRODUCTS (PRODID, NAME, DESCRIPTION) " \
> "values (123, 'Easter egg 80g', 'A longer description');"
>
> and you can execute it with::
>
> cursor.execute(sql)
>
> That would be OK when you create the database for the first time. Later
> your boss comes in and says: "We've got bigger eggs! Code 124, 150g each.
> We need them in the database". You write an sql statement similar to
> above. Some days later, they decide to sell bubble gum. Forty-two
> different sizes and flavors and brands. You don't want to write all that
> sql statements by hand. Your first thought is to build the sql text by
> pieces::
>
> sql = "insert into PRODUCTS (PRODID, NAME, DESCRIPTION) " \
> "values ("+str(prodid)+", '"+prodname+"', '"+description+"');"
>
> But then you remember to have read something about sql injection and you
> don't like that mess of " + ) ' ( anyway. After reading some articles
> about DBAPI 2, PEP 249, the MySQLdb module, you write this::
>
> sql = "insert into PRODUCTS (PRODID, NAME, DESCRIPTION) " \
> "values (%s,%s,%s);"
> cursor.execute(sql, (prodid, prodname, description))
>
> and it works fine.
>
> Note that execute has two arguments: first, a string with the sql
> statement text; second, a tuple containing the values. The %s in the sql
> text are placeholders, they're replaced with the corresponding value from
> the second argument. And there is no ' anywhere.
Well, what I did, that now works, was essentially what you suggested, and
simply assigned null values to variables that accept null values in the
database. That works. What I was trying to do was build up just those
variables that were to be updated or entered, and supply only those
arguments. At this point it is rather academic, but can that be done?
> However, if I print what that code spits out:
> >
> > sql = "'insert into products (" + col_names + ") values (" + val + ")',
> > (" +
> > col_names + ")"
> >
> > print sql
> >
> > then copy and paste it into a cursor.execute() statement, viola!
> > Everything
> > works _just_fine_. Go figure. Why??
>
> What you have done has no sense - why do you think it should work?
See above.
> pic1 = _mysql.escape_string(f)
> >
> > It does not like this (forgot error):
> >
> > pic1 = MySQLdb.Binary(f)
>
> You should make the above work. Look at the exception, read the error
> message, look at the traceback. There are a lot of info there.
Amazingly (because I thought I had tested this) both the escape string and
the db Binary work now.
> Escaping the string, I can successfully load this image into the
> > database,
> > along with all the other fields. Now, when I load an image from the form
>
Re: Orphaned child processes
[EMAIL PROTECTED] wrote: > I'm using the Python processing module. I've just run into a problem > though. Actually, it's a more general problem that isn't specific to > this module, but to the handling of Unix (Linux processes) in general. > Suppose for instance that for some reason or another, after forking > several child processes, the main process terminates or gets killed > (or segfaults or whatever) and the child processes are orphaned. Is > there any way to automatically arrange things so that they auto- > terminate or, in other words, is there a way to make the child > processes terminate when the parent terminates? > > Thank you. Put a thread in the child which reads stdin, and make stdin connect to a pipe from the parent. When the parent terminates, the child will get a SIGPIPE error and raise an exception. John Nagle -- http://mail.python.org/mailman/listinfo/python-list
Re: Tips for load balancing multiple Python apps on dual/quad core processors?
Malcolm Greene wrote: > I'm looking for tips on how to load balance running multiple Python > applications in multi-CPU environments. My understanding is that Python > applications and their threads are limited to a specific CPU. > > Background: I have a Python utility that processes email messages. I > suspect there's a lot of idle time while this utility waits on a remote > email server. While it's true that python's threads are limited to using a single CPU at a time, it sounds like your bottleneck is network IO, not CPU power. I imagine that your one CPU is doing a lot of idling, thumb-twiddling, etc., while waiting for the remote email server to respond. In such a scenario, python's threads will work fine to speed your application. On the other hand, adding CPUs to an IO-bound application isn't likely to speed it up at all. Jeffrey -- http://mail.python.org/mailman/listinfo/python-list
Re: Tips for load balancing multiple Python apps on dual/quad core processors?
"Malcolm Greene" <[EMAIL PROTECTED]> writes: > Is there a cross-platform way to monitor CPU load? Cross-platform: not that I know of. Linux: /proc/loadav (load average), /proc/cpuinfo (to figure out number of cpu's). You want the load average and # of cpu's to be about equal, i.e. all cpu's should be kept busy but not overloaded. -- http://mail.python.org/mailman/listinfo/python-list
Re: Tips for load balancing multiple Python apps on dual/quad core processors?
Malcolm Greene wrote: > I'm looking for tips on how to load balance running multiple Python > applications in multi-CPU environments. My understanding is that Python > applications and their threads are limited to a specific CPU. > > Background: I have a Python utility that processes email messages. I > suspect there's a lot of idle time while this utility waits on a remote > email server. I would like to run as many simultaneous copies of this > utility as possible without overwhelming the server these utilities are > running on. My thought is that I should write a dispatcher that monitors > CPU load and launches/cancels multiple instances of my utility with > specific job queues to process. > > Is there a cross-platform way to monitor CPU load? > > Is there a pre-existing Python module I should be looking at for > building (subclassing) my dispatcher? > As a data point for you, I wrote a multi-threaded application that used 100 threads to send about 45,000 emails in less than four hours. The single-CPU computer that processed this job wasn't using that much CPU (certainly under 50%). regards Steve -- Steve Holden+1 571 484 6266 +1 800 494 3119 Holden Web LLC http://www.holdenweb.com/ -- http://mail.python.org/mailman/listinfo/python-list
Re: A file iteration question/problem
On Apr 7, 2:09 pm, [EMAIL PROTECTED] wrote:
> Arnaud Delobelle <[EMAIL PROTECTED]> wrote:
> > def recfun(lines):
> > for line in lines:
> > # Do stuff
> > if condition:
> > recfun(lines)
>
> > lines = iter(open(filename))
> > recfun(lines)
>
> Does that work though? If you iterate through the file with the "for
> line in lines:" in the first call of recfun(lines) you surely can't do
> "for line in lines:" and get any sort of sensible result in recursive
> calls of recfun(lines) can you?
Try it! The keyword is iterator.
Here is an example of how this would work, but since you didn't
believe me I changed the context (strings not files) and I didn't make
it as simple as possible ;)
def reclist(string):
chariter = iter(string + ' ')
def rec():
l = []
word = ''
for c in chariter:
if c.isalnum():
word += c
elif word and (c.isspace() or c in '[]'):
l.append(word)
word = ''
if c == ']':
return l
elif c == '[':
l.append(rec())
return l
return rec()
>>> reclist('40 and 2 eggs but no spam')
['40', 'and', '2', 'eggs', 'but', 'no', 'spam']
>>> reclist('[[40 and 2] eggs] but [no spam]')
[[['40', 'and', '2'], 'eggs'], 'but', ['no', 'spam']]
>>>
--
Arnaud
--
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Re: Mathematical Python Library
In article <[EMAIL PROTECTED]>, Dennis Lee Bieber <[EMAIL PROTECTED]> wrote: >On Mon, 7 Apr 2008 09:05:57 -0700 (PDT), mc <[EMAIL PROTECTED]> >declaimed the following in comp.lang.python: > >> I'm looking for a library which can do mathematical stuff like >> solving equations. Or calculation the nulls of a function and so on. >> Does anyone know one? >> > Other than coding some serial/USB interface to an HP50g... > > Maybe SAGE? > sympy? > >http://www.google.com/search?hl=en&q=python+computer+algebra+system&btnG=Google+Search . . . While there are in fact several possible approaches to symbolic mani- pulation of "mathematical stuff" in Python, I STRONGLY recommend that beginners in the area look into SAGE http://www.sagemath.org/ >, already mentioned above by Dennis. SAGE is life-altering software, for those with a life focused on mathematics or related science or engineering. -- http://mail.python.org/mailman/listinfo/python-list
Re: A funnily inconsistent behavior of int and float
"Mark Dickinson" <[EMAIL PROTECTED]> wrote in message news:[EMAIL PROTECTED] | On Apr 7, 6:43 am, "Colin J. Williams" <[EMAIL PROTECTED]> wrote: | > This is good but the documentation for | > 3.0 is missing the syntax documentation | > from 2.5 | | Is | | http://docs.python.org/dev/3.0/reference/lexical_analysis.html#integer-literals | | the documentation that you're looking for? | | But it seems to me that Lie's original point isn't really | about integer *literals* anyway---it's about the behaviour | of the built-in int() function when applied to a string. So | | http://docs.python.org/dev/3.0/library/functions.html#int | | is probably the appropriate place in the documentation. And | I agree that it could be made clearer exactly what strings are | acceptable here. Agreed. It says "If radix is zero, the interpretation is the same as for integer literals." But integer literals are unsigned. Is radix 0 any different from the default of radix 10? It also says "If the argument is a string, it must contain a possibly signed number of arbitrary size, possibly embedded in whitespace." But only integers, not 'numbers' as some would understand that, are accepted. My suggestions: 1. Change signature to: int([number | string[, radix]). This makes it clear that radix can only follow a string without having to say so in the text. 2. Replace text with: Convert a number or string to an integer. If no arguments are given, return 0. If a number is given, return number.__int__(). Conversion of floating point numbers to integers truncates towards zero. A string must be a base-radix integer literal optionally preceded by '+' or '-' (with no space in between) and optionally surrounded by whitespace. A base-n literal consists of the digits 0 to n-1, with 'a' to 'z' (or 'A' to 'Z') having values 10 to 35. The default radix is 10. The allowed values are 0 and 2-36, with 0 the same as 10. If 0 is not the same as 10, the last would have to be changed, but I could not detect any difference in a quick test. After looking at any comments here, I will consider submitting these to the tracker. Terry Jan Reedy -- http://mail.python.org/mailman/listinfo/python-list
Re: reading dictionary's (key,value) from file
On Apr 7, 11:55 am, Robert Bossy <[EMAIL PROTECTED]> wrote:
> [EMAIL PROTECTED] wrote:
> > Folks,
> > Is it possible to read hash values from txt file.
> > I have script which sets options. Hash table has key set to option,
> > and values are option values.
>
> > Way we have it, we set options in a different file (*.txt), and we
> > read from that file.
> > Is there easy way for just reading file and setting options instead of
> > parsing it.
>
> > so this is what my option files look like:
>
> > 1opt.txt
> > { '-cc': '12',
> > '-I': r'/my/path/work/'}
>
> > 2opt.txt
> > { '-I': r/my/path/work2/'}
>
> > so my scipt how has dictionary
> > options = { '-cc' :'12'
> > '-I': r'/my/path/work/:/my/path/work2/'}
>
> > I am trying to avoid parsing
>
> For this particular case, you can use the optparse
> module:http://docs.python.org/lib/module-optparse.html
>
> Since you're obviously running commands with different set of options, I
> suggest you listen to Diez.
>
> Cheers,
> RB- Hide quoted text -
>
> - Show quoted text -
I think I am missing lot regarding optparser module. My only option is
to have option file, and I have couple of those..each user creates
it's own. How can optparser help me in this regard
Thank you
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Problem with smtplib and py2exe
Hi everyone,
I'm running Python 2.5.1 on an XP-Pro platform, with all the updates
(SP2, etc) installed. I have a program (send_file.py) that sends a
file to a service provider, using an ftp connection. The program
works properly, and I've created an 'exe' of it, using py2exe. It was
distrubuted to my user base a couple of weeks ago and seems to be
working well. None of the users have Python installed on their
machines, thus the need for an 'exe' for the program.
I now need to add an email function to the program, to automatically
send an email to a select user list when the program is completed.
I've made the appropriate modifications to my code, and the program
works properly when I run it from Python. When I try to make an exe
out of my new program, however, I get the following error:
Traceback (most recent call last):
File "C:/Python25/send_ftp/setup.py", line 17, in
console = [{"script": 'send_file.py'}] )
File "C:\Python25\lib\distutils\core.py", line 168, in setup
raise SystemExit, "error: " + str(msg)
SystemExit: error: command 'C:\Python25\pythonw.exe' failed with exit
status 1
The 'setup.py' script is the same one I used to generate the 'exe' of
the original program. The email-related code was added to my
'send_file.py' program as a function - it's not a separate module. If
all of the changes are commented out, the py2exe function works. But
as soon as I activate even the line "import smtplib", the py2exe
process spits out the error above.
If I put only the email portions of code in a test program, and run it
from Python, it works, but if I try make an 'exe' out of the test
program, I get the same error as above.
Is there an inherent incompatibility between smtplib and py2exe? Does
anyone have any ideas of how I can fix this problem?
--
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Re: A funnily inconsistent behavior of int and float
On Apr 7, 3:15 pm, "Terry Reedy" <[EMAIL PROTECTED]> wrote:
>
> My suggestions:
> 1. Change signature to: int([number | string[, radix]).
> This makes it clear that radix can only follow a string without having to
> say so in the text.
>
> 2. Replace text with:
> Convert a number or string to an integer. If no arguments are given,
> return 0. If a number is given, return number.__int__(). Conversion of
> floating point numbers to integers truncates towards zero. A string must
> be a base-radix integer literal optionally preceded by '+' or '-' (with no
> space in between) and optionally surrounded by whitespace. A base-n
> literal consists of the digits 0 to n-1, with 'a' to 'z' (or 'A' to 'Z')
> having values 10 to 35. The default radix is 10. The allowed values are 0
> and 2-36, with 0 the same as 10.
>
> If 0 is not the same as 10, the last would have to be changed, but I could
> not detect any difference in a quick test.
>
> After looking at any comments here, I will consider submitting these to the
> tracker.
>
> Terry Jan Reedy
Looks good! The description should probably also mention the optional
'0b', '0o' or '0x' (or '0B', '0O', '0X') allowed between the sign and
the digits (or before the digits in the case of a missing sign) when
base=2, base=8 or base=16.
The only base 0 versus base 10 difference I could find was the
following:
>>> int('033', 0)
Traceback (most recent call last):
File "", line 1, in
ValueError: invalid literal for int() with base 0: '033'
[38720 refs]
>>> int('033')
33
Mark
--
http://mail.python.org/mailman/listinfo/python-list
Re: reading dictionary's (key,value) from file
You can use execfile (or exec, in 3.0) function to execute code in a file in the present context. -- http://mail.python.org/mailman/listinfo/python-list
Re: Mathematical Python Library
Cameron Laird wrote: > In article <[EMAIL PROTECTED]>, > Dennis Lee Bieber <[EMAIL PROTECTED]> wrote: >> On Mon, 7 Apr 2008 09:05:57 -0700 (PDT), mc <[EMAIL PROTECTED]> >> declaimed the following in comp.lang.python: >> >>> I'm looking for a library which can do mathematical stuff like >>> solving equations. Or calculation the nulls of a function and so on. >>> Does anyone know one? >>> >> Other than coding some serial/USB interface to an HP50g... >> >> Maybe SAGE? >> sympy? >> >> http://www.google.com/search?hl=en&q=python+computer+algebra+system&btnG=Google+Search > . > . > . > While there are in fact several possible approaches to symbolic mani- > pulation of "mathematical stuff" in Python, I STRONGLY recommend that > beginners in the area look into SAGE http://www.sagemath.org/ >, > already mentioned above by Dennis. SAGE is life-altering software, for > those with a life focused on mathematics or related science or > engineering. +1 Jaap -- http://mail.python.org/mailman/listinfo/python-list
Re: A funnily inconsistent behavior of int and float
On Apr 7, 3:53 pm, Mark Dickinson <[EMAIL PROTECTED]> wrote:
> The only base 0 versus base 10 difference I could find was the
> following:
>
> >>> int('033', 0)
>
> Traceback (most recent call last):
> File "", line 1, in
> ValueError: invalid literal for int() with base 0: '033'
> [38720 refs]>>> int('033')
>
> 33
>
> Mark
And also things like:
>>> int('0x33')
Traceback (most recent call last):
File "", line 1, in
ValueError: invalid literal for int() with base 10: '0x33'
[38719 refs]
>>> int('0x33', 0)
51
[38719 refs]
Mark
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Data structure recommendation?
Hi all- I'm looking for a data structure that is a bit like a dictionary or a hash map. In particular, I want a mapping of floats to objects. However, I want to map a RANGE of floats to an object. This will be used for timestamped storage / lookup, where the float represents the timestamp. get(x) should return the object with the "newest" (biggest) timestamp y <= x, if it exists. Example: foo = Foo() foo.get(1.5) -> None foo.put(1.3, 'a') foo.put(2.6, 'b') foo.get(1.5) -> 'a' foo.get(7.8) -> 'b' foo.put(5.0, 'c') foo.get(7.8) -> 'c' In otherwords, by the end here, for foo.get(x), x < 1.3 maps to None, 1.3 <= x < 2.6 maps to 'a', 2.6 <= x < 5.0 maps to 'b', 5.0 <= x maps to 'c'. I know that foo.get() will be called many times for each foo.put(). Is there any way to achieve O(1) performance for foo.get(), maybe via some kind of hash function? Or is the best thing to use some kind of binary search? Thanks for any advice. -Steven -- http://mail.python.org/mailman/listinfo/python-list
Re: Data structure recommendation?
> I know that foo.get() will be called many times for each foo.put(). Is > there any way to achieve O(1) performance for foo.get(), maybe via > some kind of hash function? Or is the best thing to use some kind of > binary search? If you know something about the density of the input values, O(1) is possible. E.g if there is a guarantee that there will be between 1 and 10 values per unit of input, then truncate the "event time" to the next-lower int, and use that as an index k into a list; the list item will be a list of events between k and k+1. As you know that there is an upper bound to the number of such events (10), you know that searching the list will take bounded (i.e. constant) time. Likewise, as you know that there will be atleast one event per (k,k+1) interval, you know that you have to scan only one list. If you know no such thing, you'll have to use a binary search. Regards, Martin -- http://mail.python.org/mailman/listinfo/python-list
Re: Data structure recommendation?
Steven Clark wrote: > Hi all- > > I'm looking for a data structure that is a bit like a dictionary or a > hash map. In particular, I want a mapping of floats to objects. > However, I want to map a RANGE of floats to an object. > > This will be used for timestamped storage / lookup, where the float > represents the timestamp. > get(x) should return the object with the "newest" (biggest) timestamp > y <= x, if it exists. > Example: > > foo = Foo() > > foo.get(1.5) > -> None > foo.put(1.3, 'a') > foo.put(2.6, 'b') > foo.get(1.5) > -> 'a' > foo.get(7.8) > -> 'b' > foo.put(5.0, 'c') > foo.get(7.8) > -> 'c' > > In otherwords, by the end here, for foo.get(x), > x < 1.3 maps to None, > 1.3 <= x < 2.6 maps to 'a', > 2.6 <= x < 5.0 maps to 'b', > 5.0 <= x maps to 'c'. > > I know that foo.get() will be called many times for each foo.put(). Is > there any way to achieve O(1) performance for foo.get(), maybe via > some kind of hash function? Or is the best thing to use some kind of > binary search? > I believe the best way to implement this would be a binary search (bisect?) on the actual times, which would be O(log N). Though since they are timestamps they should be monotonically increasing, in which case at least you don't have to go to the expense of sorting them. "Some kind of hash function" won't hack it, since the purpose of a hash function is to map a large number of (possibly) evenly-distributed (potential) keys as nearly as possible randomly across a much smaller set of actual values. You might try messing around with reducing the precision of the numbers to home in on a gross region, but I am not convinced that does anything other than re-spell binary search if carried to extremes. regards Steve -- Steve Holden+1 571 484 6266 +1 800 494 3119 Holden Web LLC http://www.holdenweb.com/ -- http://mail.python.org/mailman/listinfo/python-list
Re: A funnily inconsistent behavior of int and float
"Mark Dickinson" <[EMAIL PROTECTED]> wrote in message
news:[EMAIL PROTECTED]
Thank you for the corrections. Here is my revised proposal:
int([number | string[, radix])
Convert a number or string to an integer. If no arguments are given,
return 0. If a number is given, return number.__int__(). Conversion of
floating point numbers to integers truncates towards zero. A string must
be a base-radix integer literal optionally preceded by '+' or '-' (with no
space in between) and optionally surrounded by whitespace. A base-n
literal consists of the digits 0 to n-1, with 'a' to 'z' (or 'A' to 'Z')
having values 10 to 35. The default radix is 10. The allowed values are 0
and 2-36. Base-2, -8, and -16 literals can be optionally prefixed with
0b/0B, 0o/0O, or 0x/0X, as with integer literals in code. Radix 0 means to
interpret exactly as a code literal, so that the actual radix is 2, 8, 10,
or 16, and so that int('010',0) is not legal, while int('010') is.
Terry Jan Reedy
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Re: A funnily inconsistent behavior of int and float
On Apr 8, 2:15 am, "Terry Reedy" <[EMAIL PROTECTED]> wrote:
(snip)
> 2. Replace text with:
> Convert a number or string to an integer. If no arguments are given,
> return 0. If a number is given, return number.__int__(). Conversion of
> floating point numbers to integers truncates towards zero. A string must
> be a base-radix integer literal optionally preceded by '+' or '-' (with no
> space in between) and optionally surrounded by whitespace. A base-n
> literal consists of the digits 0 to n-1, with 'a' to 'z' (or 'A' to 'Z')
> having values 10 to 35. The default radix is 10. The allowed values are 0
> and 2-36, with 0 the same as 10.
>
> If 0 is not the same as 10, the last would have to be changed, but I could
> not detect any difference in a quick test.
One thing though, I think it should say "may be surrounded by
whitespace" as opposed to "optionally surrounded by whitespace".
On Apr 7, 1:55 am, Grant Edwards <[EMAIL PROTECTED]> wrote:
> On 2008-04-06, Lie <[EMAIL PROTECTED]> wrote:
>
> > I've noticed some oddly inconsistent behavior with int and float:
>
> > Python 2.5.1 (r251:54863, Mar 7 2008, 03:39:23)
> > [GCC 4.1.3 20070929 (prerelease) (Ubuntu 4.1.2-16ubuntu2)] on linux2
> int('- 345')
> > -345
>
> > works,
>
> IMO, it oughtn't.
>
> float('- 345.083')
> > Traceback (most recent call last):
> > File "", line 1, in
> > ValueError: invalid literal for float(): - 345.083
>
> That's the behavior I'd expect.
Sorry to confuse you, by works I mean that the interpreter doesn't
complain at all, I didn't mean that it works as it should be.
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Re: Data structure recommendation?
If you can imply a partial order on your ranges then you can get O(n lg n) random access using a heap data structure. You'll have to implement your own heap, but heap search is easy to implement (it's Heapify that might require a little thinking). This will only work, of course, if your ranges are disjoint. C On Mon, Apr 7, 2008 at 4:58 PM, Steve Holden <[EMAIL PROTECTED]> wrote: > Steven Clark wrote: > > Hi all- > > > > I'm looking for a data structure that is a bit like a dictionary or a > > hash map. In particular, I want a mapping of floats to objects. > > However, I want to map a RANGE of floats to an object. > > > > This will be used for timestamped storage / lookup, where the float > > represents the timestamp. > > get(x) should return the object with the "newest" (biggest) timestamp > > y <= x, if it exists. > > Example: > > > > foo = Foo() > > > > foo.get(1.5) > > -> None > > foo.put(1.3, 'a') > > foo.put(2.6, 'b') > > foo.get(1.5) > > -> 'a' > > foo.get(7.8) > > -> 'b' > > foo.put(5.0, 'c') > > foo.get(7.8) > > -> 'c' > > > > In otherwords, by the end here, for foo.get(x), > > x < 1.3 maps to None, > > 1.3 <= x < 2.6 maps to 'a', > > 2.6 <= x < 5.0 maps to 'b', > > 5.0 <= x maps to 'c'. > > > > I know that foo.get() will be called many times for each foo.put(). Is > > there any way to achieve O(1) performance for foo.get(), maybe via > > some kind of hash function? Or is the best thing to use some kind of > > binary search? > > > I believe the best way to implement this would be a binary search > (bisect?) on the actual times, which would be O(log N). Though since > they are timestamps they should be monotonically increasing, in which > case at least you don't have to go to the expense of sorting them. > > "Some kind of hash function" won't hack it, since the purpose of a hash > function is to map a large number of (possibly) evenly-distributed > (potential) keys as nearly as possible randomly across a much smaller > set of actual values. > > You might try messing around with reducing the precision of the numbers > to home in on a gross region, but I am not convinced that does anything > other than re-spell binary search if carried to extremes. > > regards > Steve > -- > Steve Holden+1 571 484 6266 +1 800 494 3119 > Holden Web LLC http://www.holdenweb.com/ > > -- > http://mail.python.org/mailman/listinfo/python-list > -- http://mail.python.org/mailman/listinfo/python-list
Re: Problem with smtplib and py2exe
"Kevin" <[EMAIL PROTECTED]> wrote in message
news:[EMAIL PROTECTED]
| Hi everyone,
|
| I'm running Python 2.5.1 on an XP-Pro platform, with all the updates
| (SP2, etc) installed. I have a program (send_file.py) that sends a
| file to a service provider, using an ftp connection. The program
| works properly, and I've created an 'exe' of it, using py2exe. It was
| distrubuted to my user base a couple of weeks ago and seems to be
| working well. None of the users have Python installed on their
| machines, thus the need for an 'exe' for the program.
|
| I now need to add an email function to the program, to automatically
| send an email to a select user list when the program is completed.
| I've made the appropriate modifications to my code, and the program
| works properly when I run it from Python. When I try to make an exe
| out of my new program, however, I get the following error:
|
| Traceback (most recent call last):
| File "C:/Python25/send_ftp/setup.py", line 17, in
|console = [{"script": 'send_file.py'}] )
| File "C:\Python25\lib\distutils\core.py", line 168, in setup
|raise SystemExit, "error: " + str(msg)
I would go to that line in that file (it is in the except: part of a try:
statement) and file the function call that raised the exception and ...
There seems to be a DEBUG variable, which might also give more info.
| SystemExit: error: command 'C:\Python25\pythonw.exe' failed with exit
| status 1
|
| The 'setup.py' script is the same one I used to generate the 'exe' of
| the original program. The email-related code was added to my
| 'send_file.py' program as a function - it's not a separate module. If
| all of the changes are commented out, the py2exe function works. But
| as soon as I activate even the line "import smtplib", the py2exe
| process spits out the error above.
|
| If I put only the email portions of code in a test program, and run it
| from Python, it works, but if I try make an 'exe' out of the test
| program, I get the same error as above.
|
| Is there an inherent incompatibility between smtplib and py2exe? Does
| anyone have any ideas of how I can fix this problem?
tjr
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Re: A file iteration question/problem
[EMAIL PROTECTED] wrote: > I want to iterate through the lines of a file in a recursive function > so I can't use:- > > f = open(listfile, 'r') > for ln in f: > > because when the function calls itself it won't see any more lines in > the file. E.g. more fully I want to do somthing like:- > > def recfun(f) > while True: > str = readline(f) > if (str == "") > break; > # > # do various tests > # > if : > recfun(f) > Don't do that; Python doesn't have tail recursion and you'll hit the stack limit. John Nagle -- http://mail.python.org/mailman/listinfo/python-list
playing around with python
Hello all, I downloaded the source for version 2.5.2 and I played around and made some changes, but now I don't know how to compile on my machine to test them. Can someone tell me how to compile it to run on my machine? I'm trying to get familiar with it before I volunteer. Also, I'm running Unbuntu Linux. Thanks, Ronn -- http://mail.python.org/mailman/listinfo/python-list
Re: Dependency Queue
On Apr 7, 1:13 pm, "Terry Reedy" <[EMAIL PROTECTED]> wrote: > "Carl Banks" <[EMAIL PROTECTED]> wrote in message > > news:[EMAIL PROTECTED] > | I'm looking for any information about a certain kind of dynamic data > | structure. Not knowing if it has some well-known name that I could > | have Googled, I'll just call it a dependency queue. It's like a > | priority queue except instead of a strict ordering of items by > | priority, there is only a topological ordering (like you would have in > | a directed acyclic graph). > | > | To date I've been generating a dependency graph in advance every > | iteration through my main loop, doing a topsort, and executing the > | values in order (the values are callable objects--this is a > | scheduler). > | > | However, I'd like a dynamic dependency queue for two reasons: it would > | simplify things to not have to generate the whole graph in advance, > | and it could improve performance to run some tasks of the next > | iteration in the present one (this could potentially make better use > | of the dual-core and graphics hardware). > | > | I'm pretty sure I could hack out this structure on my own, but I'd > | like to see any prior information if there is any, in case anyone's > | figured out things like, Is there an easy way to detect cycles on > | insertion? and so on. > > Perhaps what you want is a dynamic DAG (directed acyclic graph) with > ordered labels. At any time, only the set of sources are eligible for > execution, so there is no reason to flatten the whole thing. I suspect > insertion with cycle detection would be easier, but I don't remember > actually seeing an algorithm. Yes, a dynamically updating DAG is probably how I'd implement it, that's straightforward enough. What I'm looking for is any prior work on uncovering properties and useful algorithms for the situations that would come up. Like is there a chapter of some book devoted to them? Carl Banks -- http://mail.python.org/mailman/listinfo/python-list
playing around with python
Hello, I download the source for -- http://mail.python.org/mailman/listinfo/python-list
Re: Orphaned child processes
In article <[EMAIL PROTECTED]>, John Nagle <[EMAIL PROTECTED]> wrote: > [EMAIL PROTECTED] wrote: > > I'm using the Python processing module. I've just run into a problem > > though. Actually, it's a more general problem that isn't specific to > > this module, but to the handling of Unix (Linux processes) in general. > > Suppose for instance that for some reason or another, after forking > > several child processes, the main process terminates or gets killed > > (or segfaults or whatever) and the child processes are orphaned. Is > > there any way to automatically arrange things so that they auto- > > terminate or, in other words, is there a way to make the child > > processes terminate when the parent terminates? > > > > Thank you. > > Put a thread in the child which reads stdin, and make stdin > connect to a pipe from the parent. When the parent terminates, > the child will get a SIGPIPE error and raise an exception. > > John Nagle That could work, but not precisely in that manner. You get SIGPIPE when you write to a closed pipe. When you read from one, you get end of file, i.e., a normal return with 0 bytes. When you test it, make sure to try a configuration with more than one child process. Since the parent holds the write end of the pipe, subsequently forked child processes could easily inherit it, and they'll hold it open and spoil the effect. Donn Cave, [EMAIL PROTECTED] -- http://mail.python.org/mailman/listinfo/python-list
pyAmazon
Anyone familiar with pyAmazon ( the latest for AWS 4.0 ), who knows
why the ItemSearch echo's the XML that is retrieved ?
My statement is
products = ecs.ItemSearch("Duma Key", SearchIndex='Books')
And the "products" list is populated okay, however before my script
ends ( executing script on DOS command line ), I get all of the XML
data scrolling on the screen.
Thanks
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Re: A funnily inconsistent behavior of int and float
Terry Reedy wrote: > "Mark Dickinson" <[EMAIL PROTECTED]> wrote in message > news:[EMAIL PROTECTED] > | On Apr 7, 6:43 am, "Colin J. Williams" <[EMAIL PROTECTED]> wrote: > | > This is good but the documentation for > | > 3.0 is missing the syntax documentation > | > from 2.5 > | > | Is > | > | > http://docs.python.org/dev/3.0/reference/lexical_analysis.html#integer-literals > | > | the documentation that you're looking for? Yes, thanks. I missed it. Colin W. > | > | But it seems to me that Lie's original point isn't really > | about integer *literals* anyway---it's about the behaviour > | of the built-in int() function when applied to a string. So > | > | http://docs.python.org/dev/3.0/library/functions.html#int > | > | is probably the appropriate place in the documentation. And > | I agree that it could be made clearer exactly what strings are > | acceptable here. > > Agreed. > > It says "If radix is zero, the interpretation is the same as for integer > literals." > But integer literals are unsigned. Is radix 0 any different from the > default of radix 10? > > It also says "If the argument is a string, it must contain a possibly > signed number of arbitrary size, possibly embedded in whitespace." But > only integers, not 'numbers' as some would understand that, are accepted. > > My suggestions: > 1. Change signature to: int([number | string[, radix]). > This makes it clear that radix can only follow a string without having to > say so in the text. > > 2. Replace text with: > Convert a number or string to an integer. If no arguments are given, > return 0. If a number is given, return number.__int__(). Conversion of > floating point numbers to integers truncates towards zero. A string must > be a base-radix integer literal optionally preceded by '+' or '-' (with no > space in between) and optionally surrounded by whitespace. A base-n > literal consists of the digits 0 to n-1, with 'a' to 'z' (or 'A' to 'Z') > having values 10 to 35. The default radix is 10. The allowed values are 0 > and 2-36, with 0 the same as 10. > > If 0 is not the same as 10, the last would have to be changed, but I could > not detect any difference in a quick test. > > After looking at any comments here, I will consider submitting these to the > tracker. > > Terry Jan Reedy > > > -- http://mail.python.org/mailman/listinfo/python-list
popen pipe limit
I'm getting errors when reading from/writing to pipes that are fairly
large in size. To bypass this, I wanted to redirect output to a file
in the subprocess.Popen function, but couldn't get it to work (even
after setting Shell=True). I tried adding ">","temp.sql" after the
password field but mysqldump gave me an error.
the code:
p1 = subprocess.Popen(["mysqldump","--all-databases","--user=user","--
password=password"], shell=True)
p2 = subprocess.Popen(["gzip","-9"], stdin=p1.stdout)
output = p2.communicate()[0]
file=open('test.sql.gz','w')
file.write(str(output))
file.close()
the output:
gzip: compressed data not written to a terminal. Use -f to force
compression.
For help, type: gzip -h
mysqldump: Got errno 32 on write
I'm using python rather than a shell script for this because I need to
upload the resulting file to a server as soon as it's done.
thanks
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