PHP mb_substr() Function

The mb_substr() is an inbuilt function in PHP that is used to extract a portion of a string, based on a specified starting position and length, while taking into account the multi-byte character encoding of the string.

Syntax:

mb_substr( string $string, int $start, ?int $length = null, ?string $encoding = null )
: string

Parameters: This function takes four parameters that are described below.

• $string: The multi-byte string from which to extract the substring.
• $start: The position in the string to start the extraction. If negative, the position is relative to the end of the string.
• $length: The length of the substring to extract. If not provided, the function returns the portion of the string starting from the $start position until the end of the string.
• $encoding: The character encoding of the string. If not provided, internal encoding is used.

Return Value: This function returns the specific portion of the string specified by the start and length parameters.

Example 1: The following program demonstrates the mb_substr() function.

PHP

<?php
$str = "Hello, world!";
$sub = mb_substr($str, -6);
echo $sub;
?>

Output:   

world!

Example 2: The following program demonstrates the mb_substr() function.

PHP

<?php
$str = "Geeks for Geeks";
$sub = mb_substr($str, 3,-6);
echo $sub;
?>

Output:

ks for  

Reference: https://www.php.net/manual/en/function.mb-substr.php