python numpy find index of value code example

Example 1: get index of element in numpy array python

itemindex = numpy.where(array==item)

Example 2: numpy find index of matching values

import numpy as np
# init arrays
a = np.array([1,2,3,2,3,4,3,4,5,6])
b = np.array([7,2,10,2,7,4,9,4,9,8])

#using enumerate, list comprehension and set
print([key for key, val in enumerate(a) if val in set(b)])
# output
# [1, 3, 5, 7]