PHP substr(): How to Extract a Substring from a String

Summary: in this tutorial, you’ll learn how to use the PHP substr() function to extract a substring from a string.

Introduction to the PHP substr() function #

The substr() function accepts a string and returns a substring from the string.

Here’s the syntax of the substr() function:

substr ( string $string , int $offset , int|null $length = null ) : stringCode language: PHP (php)

In this syntax:

$string is the input string.
$offset is the position at which the function begins to extract the substring.
$length is the number of characters to include in the substring. If you omit the $length argument, the substr() function will extract a substring from the $offset to the end of the $string. If the $length is 0, false, or null, the substr() function returns an empty string.

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

The following example uses the substr() function to extract the first three characters from a string:

<?php

$s = 'PHP substring';
$result = substr($s, 0, 3); 

echo $result;// PHPCode language: PHP (php)

In this example, the substr() function extract the first 3 characters from the 'PHP substring' string starting at the index 0.