Asked By – norio
I have a NumPy array ‘boolarr’ of boolean type. I want to count the number of elements whose values are
True. Is there a NumPy or Python routine dedicated for this task? Or, do I need to iterate over the elements in my script?
Now we will see solution for issue: How to count the number of true elements in a NumPy bool array
You have multiple options. Two options are the following.
Here’s an example:
>>> import numpy as np >>> boolarr = np.array([[0, 0, 1], [1, 0, 1], [1, 0, 1]], dtype=np.bool) >>> boolarr array([[False, False, True], [ True, False, True], [ True, False, True]], dtype=bool) >>> boolarr.sum() 5
Of course, that is a
bool-specific answer. More generally, you can use
>>> np.count_nonzero(boolarr) 5