我们如何使用usort函数执行“自然排序”

How can we perform a "natural sort" (as done by function natsort) using usort function.

Try this

<?php
function cmp($a, $b)
{
    if ($a == $b) {
        return 0;
    }
    return ($a < $b) ? -1 : 1;
}

$a = array(3, 2, 5, 6, 1);

usort($a, "cmp");

foreach ($a as $key => $value) {
    echo "$key: $value
";
}
?>