PHP preg_match（）找不到匹配项

I need to get the dates matching the format 'dd/mm', but it doesn't seem to work :

$r = 'D 07/11 A 17/11';
$pattern = '/^(0[1-9]|[12][0-9]|3[01])[-\/](0[1-9]|1[012])/';

if(preg_match($pattern, $r, $matches)) {
    print_r($matches);
}

The regex seems to be valid,i've tested it using https://regex101.com/.

You use ^ repexp character. It means: (0[1-9]|[12][0-9]|3[01])[-\/](0[1-9]|1[012]) must to be in the begining of string. Your regex will be valid on:

$r='07/11 A 17/11';

So, remove ^ character.