Re: Some PyCon videos won't play
Lee Harr miss...@hotmail.com writes: I am having a great time watching videos from PyCon. Thanks to everyone who presented, and to those who did such a great job putting the videos up at: http://pycon.blip.tv/ My trouble is that, although most of the videos play perfectly, there are a few that refuse to play at all. Like: I also had problems playing some of the videos (using gnash), but if you press files and links, then you can download the talk as an ogv file. Furthermore blip.tv provides an rss-feed with ogv-files for each channel on their site. http://pycon.blip.tv/rss Thanks to the pycon people for putting all their nice videos on the web. Niels -- http://mail.python.org/mailman/listinfo/python-list
Re: Append to an Excel file
pp parul.pande...@gmail.com writes: On Jan 9, 1:47 am, Jason Scheirer jason.schei...@gmail.com wrote: On Jan 9, 12:30 am, pp parul.pande...@gmail.com wrote: Hi All, How do I add a line to an existing file. This should append to the existing data in the excel file, which was saved previously. Thanks, PP http://pypi.python.org/pypi/xlwt Hi Jason and all, Thanks I have seen this.. my question is there a way to append to a excel file which has been closed. Any specific modes which can be added to the sheet so that it adds a line to the data which was return in some earlier running of the program. I may be wrong, but I think that you have to do the following 1) Use xlrd to read the file. This creates an xlrd.Book 2) Use xlutils to transform the xlrd.Book into a xlwt.WorkBook 3) Edit the xlwt.WorkBook 4) Save the xlwt.WorkBook https://secure.simplistix.co.uk/svn/xlutils/trunk/xlutils/docs/copy.txt Niels -- http://mail.python.org/mailman/listinfo/python-list
Re: Help understanding the decisions *behind* python?
Phillip B Oldham phillip.old...@gmail.com writes: We often find we need to do manipulations like the above without changing the order of the original list, and languages like JS allow this. We can't work out how to do this in python though, other than duplicating the list, sorting, reversing, then discarding. If you just want a one-liner, and you don't care about speed you can do the following (but I don't think this is considered best practice) x = [2,1,3] print list(sorted(x)) [1, 2, 3] print x [2, 1, 3] Niels -- http://mail.python.org/mailman/listinfo/python-list
Re: Automatic debugging of copy by reference errors?
Gabriel Genellina wrote:
I think you got in trouble with something and you're trying to avoid it
again - but perhaps this is not the right way. Could you provide some
example?
I have been using scipy for some time now, but in the beginning I made
a few mistakes with copying by reference. The following example is
exagerated
for clarity, but the principle is the same:
import os
output=[]
firstlines =[0,0]
for filename in os.listdir('.'):
try:
firstlines[0] = open(filename,r).readlines()[0]
firstlines[1] = open(filename,r).readlines()[1]
output.append((filename,firstlines))
except:continue
print output
Now some of my fortran-using friends would like to use python to
analyze their data files. I wanted them to avoid making the same
mistakes as I did so I thought it would be good if they could get some
nanny-like warnings saying: Watch out young man. If do this, then
python will behave differently from fortran and matlab. That could
teach them to do things the right way.
I am not an expert on all this, but I guessed that it would be possible
to make a set of constraints that could catch a fair deal of simple
errors such as the one above, but still allow for quite a bit of
programming.
Niels
--
http://mail.python.org/mailman/listinfo/python-list
Re: Automatic debugging of copy by reference errors?
Marc 'BlackJack' Rintsch wrote: In [EMAIL PROTECTED], Niels L Ellegaard wrote: I have been using scipy for some time now, but in the beginning I made a few mistakes with copying by reference. But copying by reference is the way Python works. Python never copies objects unless you explicitly ask for it. So what you want is a warning for *every* assignment. Maybe I am on the wrong track here, but just to clarify myself: I wanted a each object to know whether or not it was being referred to by a living object, and I wanted to warn the user whenever he tried to change an object that was being refered to by a living object. As far as I can see the garbage collector module would allow to do some of this, but one would still have to edit the assignment operators of each of the standard data structures: http://docs.python.org/lib/module-gc.html Anyway you are probably right that the end result would be a somewhat crippled version of python Niels -- http://mail.python.org/mailman/listinfo/python-list
Automatic debugging of copy by reference errors?
Is there a module that allows me to find errors that occur due to copy by reference? I am looking for something like the following: import mydebug mydebug.checkcopybyreference = True a=2 b=[a] a=4 Traceback (most recent call last): File stdin, line 1, in ? CopyByReferenceError: Variable b refers to variable a, so please do not change variable a. Does such a module exist? Would it be possible to code such a module? Would it be possible to add the functionality to array-copying in numpy? What would be the extra cost in terms of memory and CPU power? I realize that this module would disable some useful features of the language. On the other hand it could be helpful for new python users. Niels -- http://mail.python.org/mailman/listinfo/python-list
Re: About alternatives to Matlab
Jon Harrop wrote: So I'm keen to learn what Python programmers would want/expect from F# and OCaml. I think this discussion becoming is a little misguided. The real strength of scipy is the elegant notation rather than speed. Being raised with Matlab I find scipy nicely familiar, and its fast enough for many tasks. Some would argue that the strength of scipy is the weakness of ocaml. Others would disagree. That is a question of taste. My only grudge about strongly recommending scipy to friends is the way that two arrays can share the same data. This can lead to subtle errors that I will eventually be blamed for. I don't know if arrays in Matlab (or Octave) can share data, but if they do, then everything happens behind the scenes and the user does not have to worry. I would love to see a future version of numpy that was 50% slower and had a more foolproof approach to array copying. http://www.scipy.org/Tentative_NumPy_Tutorial#head-1529ae93dd5d431ffe3a1001a4ab1a394e70a5f2 Niels -- http://mail.python.org/mailman/listinfo/python-list
Re: About alternatives to Matlab
Filip Wasilewski wrote: As far as the speed comparison is concerned I totally agree that NumPy can easily outperform Matlab in most cases. Of course one can use compiled low-level extensions to speed up specific computations in Matlab, but it's a lot easier and/or cheaper to find very good tools for Python. These benchmarks are interesting. Perhaps someone could elaborate: When is python faster than Matlab and when is it slower? As far as I understand, recent versions of Matlab include a jit, but cpython does not (unless you use psyco). Can python do faster do-loops than matlab? Does the matrix backend of python perform faster than a the matrix backend of Matlab? What is going on? Thanks in advance Niels BTW: I feel obliged to provide a small link to your upcoming wavelet code for scipy. It looks promising: http://wavelets.scipy.org/moin/ -- http://mail.python.org/mailman/listinfo/python-list
Re: ANN: Python Molecular Viewer - 1.4.3
[EMAIL PROTECTED] wrote: More information can be found on our web site at http://mgltools.scripps.edu I had some trouble finding the license of the code on the webpage, but it looks like the software is free for non-commercial use. Could I convince you to make the license more visible? Please write it in the FAQ and preferably also on the home page. Thanks in advance, and good luck with the project Niels -- http://mail.python.org/mailman/listinfo/python-list
[[x,f(x)] for x in list that maximizes f(x)] --newbie help
I just started learning python and I have been wondering. Is there a short pythonic way to find the element, x, of a list, mylist, that maximizes an expression f(x). In other words I am looking for a short version of the following: pair=[mylist[0],f(mylist[0])] for x in mylist[1:]: if f(x) pair[1]: pair=[x,f(x)] -- http://mail.python.org/mailman/listinfo/python-list
Writing an xmgr/grace file as text (not interactive)
Can someone suggest a package that allows me to write a data file for xmgr. So far I have found some packages that allow me to start an interactive xmgrace session from python, but I would rather have a package that write a text file. I realize that xmgr can read text-files, and that the format of an xmgr-file is easy to read, but if someone has allready done this work then I would rather steal it and save my own time :) Thanks in advance Niels -- http://mail.python.org/mailman/listinfo/python-list
