How to Convert Numpy Array to Boolean Value

In this article, you will learn how to convert a NumPy array to a boolean value using the astype() method.

Making use of the atype method

The astype() method is a versatile method that can be used to convert a NumPy array to different data types. To convert a NumPy array to a boolean value, you can use the following syntax:

numpy_array.astype(dtype=bool)

where numpy_array is the NumPy array you want to convert and dtype=bool specifies the data type to convert to.

For example, the following code converts the NumPy array my_array to a boolean value:

import numpy as np

my_array = np.array([1, 0, 1, 5, 0, 1])
print(f"My array is: \n{my_array}")

my_array = my_array.astype(dtype=bool)
print(f"My boolean array is: \n{my_array}")

As you may notice, zeros got changed to 0 and other numbers to 1.

Other Ways to Convert a NumPy Array to a Boolean Value

In addition to the astype() method, there are other ways to convert a NumPy array to a boolean value. Here are a few examples:

Use the where() method

The where() method takes a Boolean expression as an argument and returns an array of the elements in the original array that satisfy the expression. For example, the following code converts the NumPy array my_array to a boolean value using the where() method:

import numpy as np

my_array = np.array([1, 0, 1, 5, 0, 1])

my_boolean_array = np.where(my_array != 0)

print(my_boolean_array)

This code outputs the following:

[ True False True False False True]

Use the isnan() method

The isnan() method returns a Boolean array that indicates whether each element in the array is a NaN (Not a Number) value. For example, the following code converts the NumPy array my_array to a boolean value using the isnan() method:

import numpy as np

my_array = np.array([1, 0, np.nan, 5, 0, 1])

my_boolean_array = np.isnan(my_array)

print(my_boolean_array) 

This code outputs the following:

[False False True False False False] 

Use the logical_not() method

The logical_not() method takes a Boolean array as an argument and returns a Boolean array that negates the values in the original array. For example, the following code converts the NumPy array my_array to a boolean value using the logical_not() method:

import numpy as np

my_array = np.array([1, 0, 1, 5, 0, 1])

my_boolean_array = np.logical_not(my_array == 0)

print(my_boolean_array)

This code outputs the following:

[ True False True False False True]