numpy.select

numpy.select(condlist, choicelist, default=0)

Return an array drawn from elements in choicelist, depending on conditions.

Parameters :

condlist : list of bool ndarrays

The list of conditions which determine from which array in choicelist the output elements are taken. When multiple conditions are satisfied, the first one encountered in condlist is used.

choicelist : list of ndarrays

The list of arrays from which the output elements are taken. It has to be of the same length as condlist.

default : scalar, optional

The element inserted in output when all conditions evaluate to False.

Returns :

output : ndarray

The output at position m is the m-th element of the array in choicelist where the m-th element of the corresponding array in condlist is True.

See also

where

Return elements from one of two arrays depending on condition.

take, choose, compress, diag, diagonal

Examples

>>> x = np.arange(10)
>>> condlist = [x<3, x>5]
>>> choicelist = [x, x**2]
>>> np.select(condlist, choicelist)
array([ 0,  1,  2,  0,  0,  0, 36, 49, 64, 81])