public function validateLuhn($input)
    {
        $checksum = '';
        foreach (str_split(strrev($input)) as $i => $d) {
            $checksum .= ($i %2 !== 0) ? ($d * 2) : $d;
        }
        return array_sum(str_split($checksum)) % 10 === 0;
    }
public function validateLuhn($input)
    {
        $checksum = '';
        foreach (str_split(strrev($input)) as $i => $d) {
            $checksum .= ($i %2 !== 0) ? ($d * 2) : $d;
        }
        return array_sum(str_split($checksum)) % 10 === 0;
    }
public function validateLuhn ( $ input ) { $ checksum = '' ; foreach ( str_split ( strrev ( $ input ) ) as $ i => $ d ) { $ checksum .= ( $ i % 2 !== 0 ) ? ( $ d * 2 ) : $ d ; } return array_sum ( str_split ( $ checksum ) ) % 10 === 0 ; }
Check if the input is valid luhn number

@param string $input
@return bool
@link https://gist.github.com/troelskn/1287893
Check if the input is valid luhn number