下邊提到的幾個PHP數組排序函數的排序有一些共性：

1 數組被作為排序函數的參數，排序以后，數組本身就發生了改變，函數的返回值為bool類型。

2 函數名中出現單a表示association，含義為，在按值排序的過程中，保持key=>value的對應關系不變

3 函數名中出現單k表示key，含義為，在按值排序的過程中按照數組key而不是數組的值排序

4 函數名中出現單r的表示reverse，含義為，按照跟不加r的相反的順序排列

5 函數名中出現單u的表示user-defined，含義為，使用用戶自定義函數排序，如果函數的邏輯是參數1<參數2返回負數，則按照升序排列(p1小2返負升)。

--------------------sort函數升序排序--------------------------------

bool sort ( array &$array [, int $sort_flags= SORT_REGULAR ] )

<?php$fruits = array("lemon", "orange", "banana", "apple");sort($fruits);var_dump($fruits);?>結果：array0 => string 'apple' (length=5)1 => string 'banana' (length=6)2 => string 'lemon' (length=5)3 => string 'orange' (length=6)

--------------------rsort降序排列--------------------

<?php$fruits = array("lemon", "orange", "banana", "apple");rsort($fruits);var_dump($fruits);?>結果：array0 => string 'orange' (length=6)1 => string 'lemon' (length=5)2 => string 'banana' (length=6)3 => string 'apple' (length=5)

---------------asort按照二維數組值的升序排列（保持key=>value的關聯關系）-----------

<?php$fruits = array("d" => "lemon", "a" => "orange", "b" => "banana", "c" => "apple");asort($fruits);var_dump($fruits);?>結果：array'c' => string 'apple' (length=5)'b' => string 'banana' (length=6)'d' => string 'lemon' (length=5)'a' => string 'orange' (length=6)

--------------arsort按照二維數組值的降序排列（保持key=>value的關聯關系）--------------

<?php$fruits = array("d" => "lemon", "a" => "orange", "b" => "banana", "c" => "apple");arsort($fruits);var_dump($fruits);?>結果array'a' => string 'orange' (length=6)'d' => string 'lemon' (length=5)'b' => string 'banana' (length=6)'c' => string 'apple' (length=5)

--------------------ksort按照數組的key升序排列--------------

<?php$fruits = array("d"=>"lemon", "a"=>"orange", "b"=>"banana", "c"=>"apple");ksort($fruits);var_dump($fruits);?>結果array'a' => string 'orange' (length=6)'b' => string 'banana' (length=6)'c' => string 'apple' (length=5)'d' => string 'lemon' (length=5)

---------------------krsort按照數組key的降序排列--------------------------------

<?php$fruits = array("d"=>"lemon", "a"=>"orange", "b"=>"banana", "c"=>"apple");krsort($fruits);var_dump($fruits);?>結果array'd' => string 'lemon' (length=5)'c' => string 'apple' (length=5)'b' => string 'banana' (length=6)'a' => string 'orange' (length=6)

----------------usort函數按照用戶自定義的函數排序----------------

<?phpfunction cmp($a, $b){if ($a == $b) {return 0;}return ($a < $b) ? -1 : 1;} $a = array(3, 2, 5, 6, 1); usort($a, "cmp"); var_dump($a);?>結果：array0 => int 11 => int 22 => int 33 => int 54 => int 6

-----------------uksort使用自定義函數按照數組的key排序-----------------

<?phpfunction cmp($a, $b){$a = preg_replace('@^(a|an|the) @', '', $a);$b = preg_replace('@^(a|an|the) @', '', $b);return strcasecmp($a, $b);} $a = array("John" => 1, "the Earth" => 2, "an apple" => 3, "a banana" => 4); uksort($a, "cmp"); var_dump($a);?>結果：array'an apple' => int 3'a banana' => int 4'the Earth' => int 2'John' => int 1

-------------------uasort將數組用自定義函數按照value排序，保持索引關系不變---------

<?php// Comparison functionfunction cmp($a, $b) {if ($a == $b) {return 0;}return ($a < $b) ? -1 : 1;} // Array to be sorted$array = array('a' => 4, 'b' => 8, 'c' => -1, 'd' => -9, 'e' => 2, 'f' => 5, 'g' => 3, 'h' => -4);var_dump($array); // Sort and print the resulting arrayuasort($array, 'cmp');var_dump($array);?>結果：array'a' => int 4'b' => int 8'c' => int -1'd' => int -9'e' => int 2'f' => int 5'g' => int 3'h' => int -4array'd' => int -9'h' => int -4'c' => int -1'e' => int 2'g' => int 3'a' => int 4'f' => int 5'b' => int 8

-------------------array_multisort排序多個數組或多維數組---------

<?php$ar = array(array("10", 11, 100, 100, "a"),array( 1, 2, "2", 3, 1)); array_multisort($ar[0], SORT_ASC, SORT_STRING,$ar[1], SORT_NUMERIC, SORT_DESC);var_dump($ar);?>結果：array0 => array0 => string '10' (length=2)1 => int 1002 => int 1003 => int 114 => string 'a' (length=1)1 => array0 => int 11 => int 32 => string '2' (length=1)3 => int 24 => int 1

//說明：

1 上例中：$ar數組優先按照$ar[0]的字符串值升序排列，如果字符串值相等，再按照$ar[1]數組的數字值降序排列。

2 array_multisort函數的任意一個位置的參數如果是數組，表示排序時用的值，

如果有多個數組參數，優先按照前邊的數組值進行排序，如果是常量，例如

SORT_ASC, SORT_DESC, SORT_REGULAR,SORT_NUMERIC, SORT_STRING.

表示排序方法（數組取值前優先）。