## Question

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 **

## Answer

You have multiple options. Two options are the following.

```
boolarr.sum()
numpy.count_nonzero(boolarr)
```

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 `numpy.count_nonzero`

.

```
>>> np.count_nonzero(boolarr)
5
```

This question is answered By – David Alber

**This answer is collected from stackoverflow and reviewed by FixPython community admins, is licensed under cc by-sa 2.5 , cc by-sa 3.0 and cc by-sa 4.0 **