PHP 正则表达式 - 删除所有非字母数字字符

使用 PHP 的正则表达式，可以非常方便地删除字符串中的非字母数字字符。这对于一些需要对字符串进行清理和过滤的场景非常有用，比如处理用户输入、过滤特殊字符等。

php
$text = "Hello, 2021! How are you?";
$cleanText = preg_replace("/[^a-zA-Z0-9]/", "", $text);
echo $cleanText;

php
$text = "This is a sentence! It contains some punctuation marks.";
$cleanText = preg_replace("/[[:punct:]]/", "", $text);
echo $cleanText;

php
$text = "This is a sentence with spaces.";
$cleanText = preg_replace("/\s+/", "", $text);
echo $cleanText;

php
$text = "This is * a * sentence * with * stars.";
$cleanText = preg_replace("/\*/", "", $text);
echo $cleanText;

php
$text = "This is a sentence with some special characters.";
$cleanText = preg_replace("/[^a-zA-Z0-9\s]/", "", $text);
echo $cleanText;