numpy.argwhere() in Python (original) (raw)

Last Updated : 24 Dec, 2018

**numpy.argwhere() **function is used to find the indices of array elements that are non-zero, grouped by element.

Syntax : numpy.argwhere(arr)Parameters : arr : [array_like] Input array.Return : [ndarray] Indices of elements that are non-zero. Indices are grouped by element.

Code #1 :

Python3 `

Python program explaining

argwhere() function

import numpy as geek

input array

in_arr = [[ 2, 0, 7], [ 0, 5, 9]] print ("Input array : ", in_arr)

out_arr = geek.argwhere(in_arr) print ("Output indices of non zero array element: \n", out_arr)

`

Output:

Input array : [[2, 0, 7], [0, 5, 9]] Output indices of non zero array element: [[0 0] [0 2] [1 1] [1 2]]

Code #2 :

Python3 `

Python program explaining

argwhere() function

import numpy as geek

input array

in_arr = geek.arange(8).reshape(4, 2) print ("Input array : ", in_arr)

out_arr = geek.argwhere(in_arr>4) print ("Output indices greater than 4: \n", out_arr)

`

Output:

Input array : [[0 1] [2 3] [4 5] [6 7]] Output indices greater than 4: [[2 1] [3 0] [3 1]]