Averaging over every n elements of a NumPy array

Learn, how to average over every n elements of a NumPy array in Python? By Pranit Sharma Last updated : October 10, 2023

NumPy is an abbreviated form of Numerical Python. It is used for different types of scientific operations in python. Numpy is a vast library in python which is used for almost every kind of scientific or mathematical operation. It is itself an array which is a collection of various methods and functions for processing the arrays.

Problem statement

Suppose that we are given a NumPy array and we need to create a new array which is the average over every consecutive triplet of elements so that the new array will be one-third of the size as the original.

NumPy Array - Averaging over every n elements

If the length of the array is divisible by 3, using the numpy.mean() method would be a better option where we will reshape the array by taking 3 columns of a row at a time.

Let us understand with the help of an example,

Python program for averaging over every n elements of a NumPy array

# Import numpy
import numpy as np

# Creating numpy array
arr = np.array([52,53,99,100,10,30])

# Display original array
print("Orignal array:\n",arr,"\n")

# Calculating mean
res = np.mean(arr.reshape(-1, 3), axis=1)

# Display result
print("Result:\n",res)