Is there a NumPy function to return the first index of something in an array?

Question

I know there is a method for a Python list to return the first index of something:

>>> l = [1, 2, 3]
>>> l.index(2)
1

Is

Answer 1

Note: this is for python 2.7 version

You can use a lambda function to deal with the problem, and it works both on NumPy array and list.

your_list = [11, 22, 23, 44, 55]
result = filter(lambda x:your_list[x]>30, range(len(your_list)))
#result: [3, 4]

import numpy as np
your_numpy_array = np.array([11, 22, 23, 44, 55])
result = filter(lambda x:your_numpy_array [x]>30, range(len(your_list)))
#result: [3, 4]

And you can use

result[0]

to get the first index of the filtered elements.

For python 3.6, use

list(result)

instead of

result