where function

Steven Bethard steven.bethard at gmail.com
Sun Mar 18 19:17:33 EDT 2007


vorticitywolfe at gmail.com wrote:
> Is there a function in Python analogous to the "where" function in
> IDL?
> 
> x=[0,1,2,3,4,2,8,9]
> print where(x=2)
> 
> output:
> [2,5]

If you're doing a lot of this kind of thing, you probably want to use 
numpy::

     >>> import numpy
     >>> x = numpy.array([0, 1, 2, 3, 4, 2, 8, 9])
     >>> numpy.where(x == 2)
     (array([2, 5]),)

You can find numpy here:

     http://numpy.scipy.org/

STeVe



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