PHP Function To Turn Integer To Roman Numerals

Use the following function to change any integer into a string containing the integer value as a Roman Numeral.

function integerToRoman($integer)


{


 // Convert the integer into an integer (just to make sure)


 $integer = intval($integer);


 $result = '';


 


 // Create a lookup array that contains all of the Roman numerals.


 $lookup = array('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


  $matches = intval($integer/$value);


 


  // Add the same number of characters to the string


  $result .= str_repeat($roman,$matches);


 


  // Set the integer to be the remainder of the integer and the value


  $integer = $integer % $value;


 }


 


 // The Roman numeral should be built, return it


 return $result;


}

To run the code just give the function an integer. Here are some examples.

echo integerToRoman(1).'<br />';


echo integerToRoman(42).'<br />';


echo integerToRoman(123).'<br />';


echo integerToRoman(4576).'<br />';


echo integerToRoman(1979).'<br />';

This will print out the following.

I


XLII


CXXIII


MMMMDLXXVI


MCMLXXIX

You can also give the function a string.

echo integerToRoman('765').'<br />';

Will print out DCCLXV.