用php对任意数组排序

<?php
$array = array(3, 1, 4, 1, 5, 9, 2, 6, 5, 3, 5);
sort($array);
print_r($array);
?>

<?php
$array = array("b" => "banana", "a" => "apple", "g" => "grape");
ksort($array);
print_r($array);
?>

<?php
$array = array(5, 8, 1, 9, 3);
usort($array, function($a, $b) {
    return $a <=> $b; // PHP 7+ 中的三向比较运算符
});
print_r($array);
?>

<?php
$array = array("b" => "banana", "a" => "apple", "g" => "grape");
asort($array);
print_r($array);
?>

<?php
$array = array(
    array('name' => 'Tom', 'age' => 20),
    array('name' => 'Jerry', 'age' => 18),
    array('name' => 'Mike', 'age' => 22)
);

// 按年龄升序排序
usort($array, function($a, $b) {
    return $a['age'] <=> $b['age'];
});
print_r($array);
?>