php截取指定两个字符之间的字符串

 //截取指定两个字符之间的字符串
 public function cut($begin,$end,$str){
     $b = mb_strpos($str,$begin) + mb_strlen($begin);
     $e = mb_strpos($str,$end) - $b;
     return mb_substr($str,$b,$e);
 }