<div style='color:red'>
<?php
//如果是奇数则返回
function odd($var)
{
   return($var % 2 == 1);
}
//如果是偶数则返回
function even($var)
{
   return($var % 2 == 0);
}

$nums1 = array("111"=>1, "222"=>2, "333"=>3, "444"=>4, "555"=>5);
$nums2 = $nums1;

echo "<pre>";
echo "Odd :\n";
//回调函数，如果返回true则将$array1中的数据再赋给原数组，键保持不变
print_r(array_filter($nums1, "odd"));
echo "</pre>";

echo "<pre>";
echo "Even:\n";
print_r(array_filter($nums2, "even"));
echo "</pre>";

?>
</div>