Numpy: find index of the elements within range

Question

I have a numpy array of numbers, for example,

a = np.array([1, 3, 5, 6, 9, 10, 14, 15, 56])   

I would like to find all the indexes of the elements within a specific range. For instance, if the range is (6, 10), the answer should be (3, 4, 5). Is there a built-in function to do this?

Answer 1

You can use np.where to get indices and np.logical_and to set two conditions:

import numpy as np a = np.array([1, 3, 5, 6, 9, 10, 14, 15, 56])  np.where(np.logical_and(a>=6, a<=10)) # returns (array([3, 4, 5]),) 

Answer 2

As in @deinonychusaur's reply, but even more compact:

In [7]: np.where((a >= 6) & (a <=10)) Out[7]: (array([3, 4, 5]),)