​x
 
<!DOCTYPE html>
<html>
<body>
​
<h1>正则表达式修饰符：.</h1>
​
<p>在文本 "W3School has been live since 2006." 中，有多少个任意字符或数字？</p>
​
<?php
$txt = "W3School has been live since 2006.";
$pattern = "/./";
echo preg_match_all($pattern, $txt);
?>  
​
<p>匹配到的位置如下：</p>
​
<?php
echo preg_replace($pattern, "#", $txt);
?>  
​
<p>（每个匹配项被替换为 # 字符）</p>
​
</body>
</html>