Question

I am newbie in ruby and regular expressions and I have this function write in PHP, and I would need to rewrite it to Ruby.

function date_number_id($id_number) { 
    if (preg_match('~^([0-9]{2})([0-9]{2})([0-9]{2})/([0-9]{3,4})$~', $id_number, $match)) { 
        return (strlen($match[4]) < 4 || $match[1] >= 54 ? "19" : "20") . "$match[1]-" . sprintf("%02d", $match[2] % 50) . "-$match[3]"; 
    } 
    else
    {
      return false; 
    }
} 

Could you help me please, with it?

Many thanks!

EDIT: This is a function that prints from the identification number the birthday day. The input is for example: 890807/5089

Answer 1

Unless I missed something…

def date_number_id(id_number)
  match = /^([0-9]{2})([0-9]{2})([0-9]{2})\/([0-9]{3,4})$/.match(id_number)
  if match
    return "#{match[4].to_i < 4 || match[1].to_i >= 54 ? '19' : '20'}#{match[1]}-#{sprintf("%02d", match[2].to_i % 50)}-#{match[3]}"
  else
    return false
  end
end

I think the mapping to PHP is obvious, but if there’s something you don’t understand why it is so, ask.