Count number of 1's in an array in Python

Question

I have an array A. I want to count the number of 1's in the array but I am getting an error. I present the expected output.

import numpy as np

A=np.array([0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 1, 1, 0, 0, 0, 1, 0, 0,
       0, 1, 1, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0])

B=np.count(A==1)
print(B)

The error is

in __getattr__
    raise AttributeError("module {!r} has no attribute "

AttributeError: module 'numpy' has no attribute 'count'

The expected output is

7

Answer 1

The np.count function does not exist, you can use np.count_nonzero instead.

import numpy as np

A=np.array([0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 1, 1, 0, 0, 0, 1, 0, 0,
       0, 1, 1, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0])

B=np.count_nonzero(A==1) # or just A, if you'll never have anything other than 0 or 1
print(B)