Numpy equivalent of list.index

Question

In a low-level function that is called many times, I need to do the equivalent of python\'s list.index, but with a numpy array. The function needs to return when it finds the f

Answer 1

The closest thing I could find to what you're asking for is nonzero. It may sound odd, but the documentation makes it look like it might have the desired result.

http://www.scipy.org/Numpy_Example_List_With_Doc#nonzero

Specifically this part:

a.nonzero()

Return the indices of the elements that are non-zero.

Refer to numpy.nonzero for full documentation.

See Also

numpy.nonzero : equivalent function

>>> from numpy import *
>>> y = array([1,3,5,7])
>>> indices = (y >= 5).nonzero()
>>> y[indices]
array([5, 7])
>>> nonzero(y)                                # function also exists
(array([0, 1, 2, 3]),)

Where (http://www.scipy.org/Numpy_Example_List_With_Doc#where) may also be of interest to you.