php语法如何获取生肖属相/天干地支的方法

$year = '2023';
$zodiac = array('鼠','牛','虎','兔','龙','蛇','马','羊','猴','鸡','狗','猪'); //生肖 
$tiangan = array('甲','乙','丙','丁','戊','己','庚','辛','壬','癸'); //天干
$dizhi = array('子','丑','寅','卯','辰','巳','午','未','申','酉','戌','亥'); //地支
$ganNum = substr($year,-1);
$gan = $ganNum > 3 ?  $ganNum - 3 :  $ganNum - 3 + 10; //计算天干
$diNum = fmod($year,12);
$zhi = $diNum > 3 ?  $diNum - 3 :  $diNum - 3 + 12;  //计算地支
echo '天干：'.$tiangan[$gan -1];
echo '地支：'.$dizhi[$zhi-1];
echo '生肖：'.$zodiac[$zhi -1];