php正则表达式（持续更新）

1、字符串替换多个关键字

 $pattern = array('/a/', '/a/', '/a/');
 $replacement = array('x', 'y', 'z');
 $subject = 'abcadeafg';
 $res = preg_replace($pattern, $replacement, $subject , 1);
 echo $res; // xbcydezfg