当字符串以0开头时，PHP substr

Question

Working on a way to convert the number part of a UK licence plate to that of the reg year.

The aim is to take e.g 55 / 03 / 62

And output how they should be: 2005 / 2003 / 2012

My initial plan was this:

function convertPlateYearToYYYY($vrmYear) {
  $firstDigit = substr($vrmYear, 0, 1);
  $secondDigit = substr($vrmYear, 1, 1);
  if ($firstDigit == 6) {
    $partOne = '1';
  } else {
    $partOne = '0';
  }
$date = "20" . $partOne . $secondDigit;
return $secondDigit;
}

$vrmYear = '05'

echo convertPlateYearToYYYY($vrmYear);

This works fine, but if submitting a value that starts with 0 (like in the example) the substr seems to fail and doesnt return anything. How do I overcome this?

Answer 1

First of all you're using return $secondDigit; when I think you want to do return $date; in your function.

Without going into further discussion about your question, here's a working solution accessing the first and second digits of your string as an array instead of using substr:

function convertPlateYearToYYYY($vrmYear) {
    $firstDigit  = $vrmYear[0];
    $secondDigit = $vrmYear[1];

    if (6 == $firstDigit) {
        $partOne = '1';
    } else {
        $partOne = '0';
    }

    $date = "20{$partOne}{$secondDigit}";

    return $date;
}

$vrmYear = '05';

echo convertPlateYearToYYYY($vrmYear);

Working example in Codepad