Numpy char.find() Tutorial | Python Programming

Introduction

In this tutorial, we will cover the Numpy char.find() function. This function is used to find substrings inside an array of strings. It returns the index of the first occurrence of the substring. The char.find() function is similar to the str.find() function in Python.

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Skills Graph

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Import Numpy Library

In this step, we will import the Numpy library using the import numpy statement.

import numpy as np

Create an Array of Strings

In this step, we will create an array of strings using the np.array() function.

arr = np.array(['AAAabbbbbxcccccyyysss', 'AAAAAAAaattttdsxxxxcccc', 'AAaaxxxxcccutt', 'AAaaxxccxcxXDSDdscz'])

Find Substring in the Array

In this step, we will find a substring inside the array using the np.char.find() function. The first parameter is the array, the second parameter is the substring we want to find. We can also provide the range in which we want to search for the substring using the optional start and end parameters.

print(np.char.find(arr, 'xc'))

Find Substring within a Range

In this step, we will find a substring within a specific range using the np.char.find() function again. This time we will use the start parameter to specify the range.

print(np.char.find(arr, 'xc', start=3))

Find Substring after a Specific Index

In this step, we will find a substring after a specific index using the np.char.find() function. We will use the start parameter again to specify the index.

print(np.char.find(arr, 'xc', start=8))

Handle Non-Existent Substrings

In this step, we will handle non-existent substrings using the np.char.find() function. We will use an array that doesn't contain the substring and provide a range that doesn't contain the substring.

arr = np.array(['AAAabbbbbxcccccyyysss', 'AAAAAAAaattttds', 'AAaaxcutt', 'AAaaxXDSDdscz'])
print(np.char.find(arr, 'xc'))
print(np.char.find(arr, 'xc', start=8))

Summary

In this tutorial, we learned about the np.char.find() function in the Numpy library. We learned how to find substrings in an array of strings using the function and how to provide ranges to search for the substrings. We also learned how to handle non-existent substrings.

Find Substring Using Numpy Char Find Function