How to Convert NumPy Array of Floats into Integers

In this article, we will see how to convert NumPy Array of Floats into Integers. We are given a NumPy array of float-type values. Our task is to convert all float-type values of Numpy array to their nearest array of integer values.

Input: [1.2, 4.5, 9.1, 6.5, 8.9, 2.3, 1.2]

Output: [1, 4, 9, 6, 8, 2, 1]

Convert NumPy Array of Floats into Integers in 1-D Array

Various methods to convert float values in our NumPy array to array of nearest integer values in Python are mentioned below :

1. Naive Approach

A simple way to convert a float to an integer is by using the int() or round() function. Using int() will drop decimal part while using round() will round the float to nearest integer.

import numpy as np
org = np.array([1.2, 3.4, 5.6, 7.8, 9.1, 11.2, 14.5, 16.7])
print("Original Array : ")
print(org, "\n")
integer_array = np.array([int(i) for i in org])
print("Integer Array : ")
print(integer_array, "\n")
round_array = np.array([round(i) for i in org])
print("Round Array : ")
print(round_array)

Output

2. Using numpy.astype()

We are using numpy.astype() which is one of the most efficient ways to convert a NumPy array from one data type to another. Along with numpy.astype(), round() must be used to obtain precise values. We had added both methods with and without round().

import numpy as np
org = [1.2, 3.4, 5.6, 7.8, 9.1, 11.2, 14.5, 16.7]
org = np.array(org)
print("Original Array : ")
print(org, "\n")
integer_array = org.astype(int)
print("Integer Array : ")
print(integer_array, "\n")
round_array = np.round(org).astype(int)
print("Round Array : ")
print(round_array)

Output

3. Using numpy.asarray()

We are using numpy.asarray() to convert NumPy Array of floats into integers. It is similar to astype() but it is slightly faster in some cases because it doesn’t need to create a copy of the array if the data type is already the same.

import numpy as np
org = [1.2, 4.5, 9.1, 6.5, 8.9, 2.3, 1.2]
org = np.array(org)
print("Original Array : ")
print(org, "\n")
new = np.asarray(org, dtype="int")
print("New Array : ")
print(new)

Output

4. Using np.int_()

The np.int_() method is another way to convert float arrays into integers. It works similarly to astype() but it is a more specialized method for NumPy arrays.

import numpy as np
org = [1.2, 4.5, 9.1, 6.7, 8.9, 2.8, 1.7]
org = np.array(org)
print("Original Array : ")
print(org, "\n")
integer_array = np.int_(org)
print("Integer Array : ")
print(integer_array, "\n")
round_array = np.round(org)
round_array = np.int_(round_array)
print("Round Array : ")
print(round_array)

Output

Convert NumPy Array of Floats into Integers in 2-D Array

Now we will see how to convert numpy array into 2D integer array. We will use same methoda discussed above:

1. Naive Approach

This implementation is same as we saw in 1-D array. We are here using explicit type casting too here.

import numpy as np
org = np.array([
    [1.2, 2.3, 3.4],
    [0.1, 1.3, 2.6],
    [1.5, 4.5, 9.2]])
print("Original Array : ")
print(org, "\n")
new = []
for i in range(org.shape[0]):
    helper = []
    for j in range(org.shape[1]):
        helper.append(int(org[i, j]))
    new.append(helper)
integer = np.array(new)
print("Integer Array : ")
print(integer)

Output

2. Using numpy.astype()

In this example, we are using numpy.astype() similar to 1-D array. Just call method to the whole 2-D array at once.

import numpy as np
org = np.array([
    [1.2, 2.3, 3.4],
    [0.1, 1.3, 2.6],
    [1.5, 4.5, 9.2]])
print("Original Array : ")
print(org, "\n")
integer = org.astype(int)
print("Integer Array : ")
print(integer)

Output

3. Using numpy.asarray()

It takes whole 2-D array at once and then convert it into desired data type which is passed through the function.

import numpy as np
org = np.array([
    [1.2, 2.3, 3.4],
    [0.1, 1.3, 2.6],
    [1.5, 4.5, 9.2]])
print("Original Array : ")
print(org, "\n")
integer = np.asarray(org, dtype=int)
print("Integer Array : ")
print(integer)

Output

4. Using np.int_()

import numpy as np
org = np.array([
    [1.2, 2.3, 3.4],
    [0.1, 1.3, 2.6],
    [1.5, 4.5, 9.2]])
print("Original Array : ")
print(org, "\n")
integer = np.int_(org)
print("Integer Array : ")
print(integer)

Output

Converting NumPy arrays of floats to integers can be done using various methods where each offers some advantages. However for simplicity and ease of use numpy.astype() becomes best choice for both 1-D and 2-D arrays.