Questions on migrating from Numeric/Scipy to Numpy

[Robert Kern]

vj wrote:
>> Note that the mask needs to be a bool array.
> 
>>>> mask = zeros(5)
>>>> mask = zeros(5, numpy.int8)
>>>> mask[1] = True
>>>> mask[2] = True
>>>> a = zeros(5)
>>>> a[mask] = [100, 200]
>>>> a
> array([ 100.,  100.,    0.,    0.,    0.])
> 
> I found this strange. It should just give an error if you try to use a
> mask array of non booleans.

No, it simply does something different. Boolean arrays apply as a mask. Integer
arrays apply as indices into the array.

-- 
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