Date to Roman Numerals

function numberToRoman($num) {
    // Make sure that we only use the integer portion of the value
    $n = intval($num);
    $result = '';

    // Declare a lookup array that we will use to traverse the number:
    $lookup = [
        'M' => 1000,
        'CM' => 900,
        'D' => 500,
        'CD' => 400,
        'C' => 100,
        'XC' => 90,
        'L' => 50,
        'XL' => 40,
        'X' => 10,
        'IX' => 9,
        'V' => 5,
        'IV' => 4,
        'I' => 1,
    ];

    foreach ($lookup as $roman => $value) {
        // Determine the number of matches
        $matches = intval($n / $value);

        // Store that many characters
        $result .= str_repeat($roman, $matches);

        // Substract that from the number
        $n = $n % $value;
    }

    // The Roman numeral should be built, return it
    return $result;
}

 // Will output MMXI
echo numberToRoman(2011);