array_filter

1,'b'=>2,'c'=>3,'d'=>false,'e'=>'');
$b = array(6,7,8);

print_r(array_filter($a, 'odd'));
print_r(array_filter($b, 'even'));
print_r(array_filter($a));
输出：
Array
(
    [a] => 1
    [c] => 3
)
Array
(
    [0] => 6
    [2] => 8
)
Array
(
    [a] => 1
    [b] => 2
    [c] => 3
)