掌握PHP中对数组进行排序的正确姿势

<?php
$arr1 = array(3,1,5,2,0);
sort($arr1);
print_r($arr1);
echo "<br>";

$arr2 = array(3,1,5,2,0);
rsort($arr2);
print_r($arr2);
?>

输出：Array ( [0] => 0 [1] => 1 [2] => 2 [3] => 3 [4] => 5 )
      Array ( [0] => 5 [1] => 3 [2] => 2 [3] => 1 [4] => 0 )

<?php
$fruits1 = array("d" => "lemon", "a" => "orange", "b" => "banana", "c" => "apple");
arsort($fruits1);
foreach ($fruits1 as $key => $val) {
    echo "$key = $val;";
}
echo "<br>";
$fruits2 = array("d" => "lemon", "a" => "orange", "b" => "banana", "c" => "apple");
asort($fruits2);
foreach ($fruits2 as $key => $val) {
    echo "$key = $val\n";
}
?>

输出：a = orange;d = lemon;b = banana;c = apple;
      c = apple b = banana d = lemon a = orange

<?php
$fruits1 = array("d"=>"lemon", "a"=>"orange", "b"=>"banana", "c"=>"apple");
krsort($fruits1);
foreach ($fruits1 as $key => $val) {
    echo "$key = $val\n";
}
echo "<br>";

$fruits2 = array("d"=>"lemon", "a"=>"orange", "b"=>"banana", "c"=>"apple");
ksort($fruits2);
foreach ($fruits2 as $key => $val) {
    echo "$key = $val\n";
}
?>

输出：d = lemon c = apple b = banana a = orange
      a = orange b = banana c = apple d = lemon