numpy.flatnonzero() in Python
Last Updated : 28 Nov, 2018
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numpy.flatnonzero()function is used to Compute indices that are non-zero in the flattened 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 : Working
# 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)
Input array : [-3 -2 -1 0 1 2 3] Indices of non zero elements : [0 1 2 4 5 6]Code #2 : Using the indices of the non-zero elements as an index array.
# Python program using the indices of the non-zero
# elements as an index array to extract these elements
out_arr = arr.ravel()[geek.flatnonzero(arr)]
print ("Output array of non-zero number: ", out_arr)
Output array of non-zero number: [-3 -2 -1 1 2 3]
