How to count the number of true elements in a NumPy bool array

Question

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

Answer 1

boolarr.sum(axis=1 or axis=0)

axis = 1 will output number of trues in a row and axis = 0 will count number of trues in columns so

boolarr[[true,true,true],[false,false,true]]
print(boolarr.sum(axis=1))

will be (3,1)