NumPy amax()

Summary: in this tutorial, you will learn how to use the numpy amax() function to find the maximum element in an array.

Introduction to the NumPy amax() function

The amax() function returns the maximum element of an array or maximum element along an axis. The following shows the syntax of the amax() function:

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

The amax() function is equivalent to the max() method of the ndarray object:

ndarray.max(axis=None, out=None, keepdims=False, initial=<no value>, where=True)Code language: Python (python)

NumPy amax() function examples

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

1) Using numpy amax() function on 1-D array example

The following example uses the numpy amax() function to find the maximum value in a 1-D array:

import numpy as np


a = np.array([1, 2, 3])
min = np.amax(a)
print(max)Code language: Python (python)

Output:

1Code language: Python (python)

How it works.

First, create a new array that has three numbers 1, 2, and 3:

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

Second, find the maximum number using the amax() function:

max = np.amax(a)Code language: Python (python)

Third, display the result:

print(max)Code language: Python (python)

2) Using numpy amax() function on multidimensional array examples

The following example uses the amax() funciton to find the maximum number in a 2-D array:

import numpy as np

a = np.array([
    [1, 2],
    [3, 4]]
)
max = np.amax(a)
print(max)Code language: Python (python)

Output:

1Code language: Python (python)

If you want to find the maximum value on each axis, you can use the axis argument. For example, the following uses the amax() function to find the maximum value on axis 0:

import numpy as np

a = np.array([
    [1, 2],
    [3, 4]]
)
max = np.amax(a, axis=0)
print(max)Code language: Python (python)

Output:

[3 4]Code language: Python (python)

Similarly, you can use the amax() function to find the maximum value on axis 1:

import numpy as np

a = np.array([
    [1, 2],
    [3, 4]]
)
max = np.amax(a, axis=1)
print(max)Code language: Python (python)

Output:

[2 4]Code language: Python (python)

Summary

• Use the numpy amax() function to find the maximum element in an array or maximum element along an axis.