Common PHP String Manipulation Functions and Examples

PHP string functions are a core part of the language, and this guide covers the most commonly used methods for extracting substrings.

1. substr() extracts a portion of a string based on start position and length.

<?php
$str = "laravel";
echo substr($str,3); // avel
echo "<br/>";
echo substr($str,2,4); // rave
echo "<br/>";
echo substr($str,-3); // vel
?>

The outputs are avel, rave, and vel respectively.

2. mb_substr() handles multibyte characters such as Chinese, requiring the php_mbstring extension.

<?php
echo mb_substr("文字内容",2,1,"UTF-8"); // 内
?>

Output: 内.

To obtain the part of a string before a certain number of characters, calculate the total length and subtract the desired offset:

<?php
$weishu = 3;
echo mb_substr("文字内容", 0, mb_strlen("文字内容", 'utf8') - $weishu); // 文
?>

Result: 文.

3. Using stripos() with substr() to locate a character and extract substrings to the left or right of it.

<?php
echo substr("abcde", stripos("abcde", "c")); // cde
echo "<br/>";
echo substr("abcde", 0, stripos("abcde", "c")); // ab
?>

Outputs are cde and ab.

4. Direct character access by index using array syntax.

<?php
$str = "laravel";
echo $str[3]; // a
?>

Output: a.