<?php

// 将文本中的年份增加一年.

$text = "April fools day is 04/01/2002\n";

$text.= "Last christmas was 12/24/2001\n";

// 回调函数

function next_year($matches)

{

// 通常: $matches[0]是完成的匹配

// $matches[1]是第一个捕获子组的匹配

// 以此类推

return $matches[2];

}

echo preg_replace_callback(

"|(\d{2}/\d{2}/)(\d{4})|",

"next_year",

$text);

?>

//返回的是第二个子组的匹配项（一个括号为一个子组）

April fools day is 2002

Last christmas was 2001