Numeric and matlab

[Brian Blais]

Hello,

Most of my experience is with Matlab/Octave, so I am a Python newbie (but enjoying 
it! :)  )

There are a lot of things that I do in Matlab that I'd like to know the proper way to 
do in Python.  Here are a few:

MATLAB:

	% example vectors
	a=1:10;
	b=-5:.1:5;

	% set all the values above 5 equal to 6
	idx=find(a>5);
	a(idx)=6;

	% extract elements

	idx=find(b>0)
	b=b(idx);

	% meshgrid...usually to go through all possibly values of a parameter

	[x,y]=meshgrid(1:10,-5:.1:5)
	x=x(:); y=y(:);
	for i=1:length(x)
	  % do something with x(i) and y(i)
	end


I'm sure there are more, but these jump out at me as I'm going.  It seems as if the 
idx=find() stuff can be done with Numeric.nonzeros(), but you can't index with that, like

a=Numeric.arange(1,11,1)
idx=Numeric.nonzeros(a)
a=a[idx]   % doesn't work

and what about meshgrid?  Do I use the fromfunction() in some way?  Is there a 
resource that goes through comparisons like this?


thanks,


		Brian Blais
-- 
-----------------

             bblais at bryant.edu
             http://web.bryant.edu/~bblais