PHP Number and strings validations

1. to check a valid phone number for Pakistan e.g 03001234567     $number_pattern=”/^3[0-9]{9}$/”;     $phoneNumber=03465315155    $numberFormat = preg_match($Msisdn_pattern , $phoneNumber); 2. Format a number for proper usage     $phoneNumber=03465315155;    $phoneNumber=’0092′.substr($_REQUEST[“M”],-10);