php regix patern check

i need a function for check regex

$str = "/mypage/6";
$str2 = "/mypage/{id}";
function check($str,$str2){
  if(regex($str,$str2)){ // check and return number here
    return $number;
  }else{
    return false;
  }
}

I need a function that will do this to me. could it be ?