3v4l.org

run code in 300+ PHP versions simultaneously
<?php $str = "QR12345678"; var_dump( preg_match('/^[A-Z]{1,3}[0-9]{4,10}$/', $str) ); var_dump( preg_match('/^[A-Z]{1,3}?[0-9]{4,10}$/', $str) ); var_dump( preg_match('/([A-Z]{1,3})?[0-9]{4,10}$/', $str) ); var_dump( preg_match('/^([A-Z]{1,3})?[0-9]{4,10}$/', $str) ); var_dump( preg_match('/[A-Z]{0,3}[0-9]{4,10}/', $str) ); var_dump( preg_match('/([A-Z]{1,3})*[0-9]{4,10}$/', $str) );

preferences:
35.59 ms | 402 KiB | 5 Q