numpy.flatnonzero () in Python

numpy.flatnonzero() is used to compute indices that are not zero in the simplified version of arr.

Syntax : numpy.flatnonzero(arr)

Parameters:
arr: [array_like] Input array.

Return: ndarray
Output array, containing the indices of the elements of arr.ravel () that are non-zero.

Code # 1: Work

# Python program explaining
# flatnonzero () function

 

import numpy as geek

arr = geek.arange ( - 3 , 4 )

 

print ( "Input array:" , arr)

 

out_arr = geek.flatnonzero (arr)

print ( "Indices of non zero elements : " , out_arr) 

Output:

 Input array: [-3 -2 -1 0 1 2 3] Indices of non zero elements: [0 1 2 4 5 6] 

Code # 2: Using indices of non-zero elements as an index array.

# Python program using nonzero indices
# elements as an indexed array for retrieving these elements

 

out_arr = arr.ravel () [geek.flatnonzero (arr)]

  

print ( "Output array of non-zero number: " , out_arr) 

Output:

 Output array of non-zero number: [-3 -2 -1 1 2 3]