In [3]: arr Out[3]: array([[1, 2, 0, 3], [3, 9, 0, 4]]) In [4]: np.count_nonzero(arr==0) Out[4]: 2 In [5]:def func_cnt(): for arr in arrs: zero_els = np.count_nonzero(arr==0) # here, it counts the frequency of zeroes actually