NumPy Count Function

Introduction

In this lab, we will cover the NumPy count() function, which is a very useful method to count the number of occurrences of a given substring inside an array or a string.

VM Tips

After the VM startup is done, click the top left corner to switch to the Notebook tab to access Jupyter Notebook for practice.

Sometimes, you may need to wait a few seconds for Jupyter Notebook to finish loading. The validation of operations cannot be automated because of limitations in Jupyter Notebook.

If you face issues during learning, feel free to ask Labby. Provide feedback after the session, and we will promptly resolve the problem for you.

Skills Graph

Import Required Module

We start by importing the NumPy module using the import statement.

import numpy as np

Define String Array

We define a NumPy array of strings, which we will use for our example.

str1 = np.array(['ooooaaaaqqqk','ccccvvvvvaaaao','ggghhhjjjsskkka'])

Count Occurrences of Substring

We use the count() function to count the number of occurrences of a specific substring inside the array.

y = np.char.count(str1,'a')

Print Results

We print the results of the count function for the selected substring.

print(y)

Count Multiple Substrings

We use the count() function to count the number of occurrences of multiple substrings inside the array.

z = np.char.count(str1,['k','o'])

Print Results

We print the results of the count function for the selected substring.

print(z)

Limit Search Range

We use the count() function to count the number of occurrences of a specific substring inside a specific range inside the array.

x = np.char.count(str1,'a',0,7)

Print Results

We print the results of the count function for the selected substring inside the specific range.

print(x)

Summary

In this lab, we covered the count() function of the NumPy library with three examples that helped us understand how to use it in different scenarios. The count() function helps to count the number of occurrences of a specific substring inside an array or a string.