php字符串替换函数

	/*** @param str 字符串* @param start  开始的数* @param leftintheend  后面的数* @author an* */public function replaceInnerLetter($str,$start=3,$leftintheend=0,$repalce="*",$middleleght=6){$length = mb_strlen($str,"utf-8");$alllength = ($start+$leftintheend);if($length <= $alllength){return $str;}else{$repeadleght = $length-$alllength;if($repeadleght > $middleleght){$repeadleght = $middleleght;}return mb_substr($str,0,$start,"utf-8").str_repeat($repalce,$repeadleght).mb_substr($str,$length-$leftintheend,$leftintheend,"utf-8");}}