I have a numpy array with dim (157,1944).
I want to get all unique indices for each row that has Nonzero element.
example: [[0,0,3,4], [0,0,1,1]] ----> [2,3]
If you look each row, there is a Non Zero element on position [2, 3]
So if I have
i should get [1,2,3] because index 0 has no Nonzero element for all row
Not sure if your question is completely defined. However, say we start with
import numpy as np a = np.array([[0,0,3,4], [0,0,1,1]])
>>> np.nonzero(np.all(a != 0, axis=0)) array([2, 3])
are the indices of the columns for which none of the rows are nonzero, and
>>> np.nonzero(np.any(a != 0, axis=0)) array([2, 3])
are the indices of the columns for which not all of the rows are zero (it happens to be the same for the example you gave).