NumPy any()

Summary: in this tutorial, you’ll learn how to use the numpy any() function that returns True if any element in an array evaluates True.

Introduction to the numpy any() function

The numpy any() function returns True if any element in an array (or along a given axis) evaluates to True.

Here’s the syntax of the any function:

numpy.any(a, axis=None, out=None, keepdims=<no value>, *, where=<no value>)Code language: Python (python)

In this syntax, a is a numpy array or any object that can be converted to an array e.g., a list.

Typically, the input array contains numbers. In the boolean context, all non-zero numbers evaluate to True while zero evaluates to False. Therefore, the any() function returns True if any number in the array is nonzero or False if all numbers are zero.

NumPy any() function examples

Let’s take some examples of using the any() function.

1) Using numpy any() function on 1-D array examples

The following example uses the any() function to test whether any number in an array are non-zero:

import numpy as np

result = np.any([0, 1, 2, 3])
print(result)Code language: Python (python)

Output:

TrueCode language: Python (python)

The result is True because the array of three non-zero numbers.

import numpy as np


result = np.any(np.array([0, 0]))
print(result)Code language: Python (python)

Output:

FalseCode language: Python (python)

This example returns False because all numbers in the array are zero. In fact, you can pass any object that can be converted into a list to the any() function. For example:

import numpy as np


result = np.any([0, 0])
print(result)Code language: Python (python)

Output:

FalseCode language: Python (python)

2) Using numpy any() function with a multidimensional array example

The following example uses the any() function to test if any elements of a multidimensional array evaluate to True:

import numpy as np

a = np.array([[0, 1], [2, 3]])
result = np.any(a)
print(result)Code language: Python (python)

Output:

TrueCode language: Python (python)

Also, you can evaluate elements along an axis by passing the axis argument like this:

import numpy as np

a = np.array([
    [0, 0],
    [0, 1]
])
result = np.any(a, axis=0)
print(result)Code language: Python (python)

Output:

[False  True]Code language: Python (python)

And axis-1:

import numpy as np

a = np.array([
    [0, 0],
    [0, 1]
])
result = np.any(a, axis=1)
print(result)Code language: Python (python)

Output:

[False  True]Code language: Python (python)

Summary

• Use the numpy any function to test whether any element in an array or along an axis evaluates to True.