​x
 
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<html>
<body>
​
<h1>正则表达式修饰符：m</h1>
​
<p>在以下文本中，短语 "you" 在行首出现了多少次：</p>
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<pre>you are better than
you think</pre>
​
<?php
$txt = "you are better than\nyou think";
$pattern = "/^you/m";
echo preg_match_all($pattern, $txt);
?>  
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<p>匹配到的位置如下：</p>
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<pre>
<?php
echo preg_replace($pattern, "#", $txt);
?>  
</pre>
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<p>（每个匹配项都被替换为 # 字符）</p>
​
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</html>