preg_replace_callback

 'world wide web',		'irs' => 'internal revenue service',	    'pdf' => 'portable document format');	//echo $m[0].",".$m[1]."
";		if (isset($acs[$m[1]]))		return $m[1]."(".$acs[$m[1]].")";	else				return $acs[$m[1]];}$text = "wef irs rawfg www h pdf awf";$newtext = preg_replace_callback("/(.*)<\/aaa>/U","ac",$text);print_r ($newtext);?>

回复讨论(解决方案)

$m[0]的值带标签irswww

没懂你的意思
$m[0] 与 $m[1] 是不相等的

$m[0]的值带标签irswww