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网上一段简略的preg_match替换 不明
- WBOYOriginal
- 2016-06-13 12:36:381020browse
网上一段简单的preg_match替换 不明
<br />
$string = "Is is the cost of of gasoline going up up"; <br />
$pattern = "/\b([a-z]+) \\1\b/i"; <br />
if(preg_match($pattern, $string,$arr)){<br />
print_r($arr);<br />
echo preg_replace($pattern, '$1', $string);<br />
}<br />
输出
<br />
Array<br />
(<br />
[0] => Is is<br />
[1] => Is<br />
)<br />
Is the cost of gasoline going up<br />
我理解的preg_match（$pattern,$repalce,$subject）是用pattern从subject匹配到各个分组，然后用replace规定的显示方式，重新输出
$pattern = "/\b([a-z]+) \\1\b/i" 匹配到的只有Is is 和Is
重新输出怎么会输出一整句话 Is the cost of gasoline going up
还有什么时候用$1 什么时候用\\1 获取子模式匹配的内容 在双引号和单引号里又有什么要求？
php?正则
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