​x
 
<!DOCTYPE html>
<html>
<body>
​
<h1>正则表达式修饰符：o{3}</h1>
​
<p>在文本 "W3School is goood" 中，有多少个连续出现 3 个 o（ooo）的情况？</p>
​
<?php
$txt = "W3School is goood";
$pattern = "/o{3}/";
echo preg_match_all($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>