[SciPy-user] Vector indexing

Robert Kern robert.kern at gmail.com
Sun Jun 4 19:17:39 CDT 2006


David Grant wrote:
> Vector indexing question:
> 
> a=rand(10,10)
> 
> 1) a[0:3, 0:3] #gives me the first 3 rows and columns
> 
> 2) a[range(2),range(2)] gives me a one-dimensional array of elements [0,0], 
> [1,1], [2,2]

Actually, it gets you array([a[0,0], a[1,1]]).

> How do I do 1) using some on-the-fly generated array?

Slice objects.

>>> a[slice(0, 3), slice(0, 3)]
array([[ 0.83840663,  0.36944056,  0.48230632],
       [ 0.04508558,  0.25772124,  0.62787961],
       [ 0.0455162 ,  0.69427227,  0.26374691]])

-- 
Robert Kern

"I have come to believe that the whole world is an enigma, a harmless enigma
 that is made terrible by our own mad attempt to interpret it as though it had
 an underlying truth."
  -- Umberto Eco



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