php preg

定义和用法

preg_replace 执行一个正则表达式的搜索和替换

语法

preg_replace (pattern ,replacement ,subject,limit,count ) 参数描述pattern正则表达式(字符串或字符串数组)replacement用于替换的字符串或字符串数组subject要进行搜索和替换的字符串或字符串数组。limit可选。每个模式在每个subject上进行替换的最大次数。默认是 -1(无限)。cout可选。完成的替换次数

例子 1

<?php$string = 'April 15, 2003';$pattern = '/(\w+) (\d+), (\d+)/i';$replacement = '${1}1,$3';// $1对应(\w+),${1}1是区别$11,说明是$1和1不是$11,$3对应(\d+)echo preg_replace($pattern, $replacement, $string);?>

输出：

April1,2003

例子 2

<?php$patterns = array ('/(19|20)(\d{2})-(\d{1,2})-(\d{1,2})/', '/^\s*{(w+)}\s*=/');$replace = array ('\3/\4/\1\2', '$\1 =');// \3对应(\d{1,2}),\4对应后一个(\d{1,2}),echo preg_replace($patterns, $replace, '{startDate} = 1999-5-27');?>

输出：

$startDate = 5/27/1999

例子 3

<?php// 把heigth高度属性删除，并添加width="100%"$str = '<div><p>12312321</p><img src="xx.jpg" height="213" /><span>111</span><img src="xz.jpg" /></div>';$str = preg_replace("/height\=\"[0-9]+?\"/","",$str);$str1 = preg_replace("/src=\"(.+?)\"/","src=\"$1\" width=\"100%\"",$str);print_r($str1);