php的排序函数

sort(): 将一个数组元素从低到高进行简单排序，这个函数既可以按数字大小排列也可以按字母顺序排列。

Listing A<?php  $data = array(5,8,1,7,2);  sort($data);  print_r($data);?>输出结果如下所示：Array ([0] => 1[1] => 2[2] => 5[3] => 7[4] => 8)

rsort(): 对数组元素进行从高到低的倒排，同样可以按数字大小排列也可以按字母顺序排列。

<?php     $data = array(5,8,1,7,2);rsort($data); print_r($data);?>它的输出结果如下：Array ([0] => 8[1] => 7[2] => 5[3] => 2[4] => 1)

ksort(): 根据关键字进行排序的函数，同时，它在排序的过程中会保持关键字的相关性。

<?php     $data = array("US" => "United States", "IN" => "India", "DE" => "Germany", "ES" => "Spain");    ksort($data);    print_r($data);?>它的输出结果如下：Array ([DE] => Germany[ES] => Spain[IN] => India[US] => United States)

krsort(): 根据关键字对数组进行倒排。

<?php     $data = array("US" => "United States", "IN" => "India", "DE" => "Germany", "ES" => "Spain");    krsort($data);    print_r($data);?>它的输出结果如下：Array ([US] => United States[IN] => India[ES] => Spain[DE] => Germany)

asort(): 使用值排序来取代关键字排序，请注意关键字-值之间的联系会始终保持。

<?php     $data = array("US" => "United States", "IN" => "India", "DE" => "Germany", "ES" => "Spain");    asort($data);    print_r($data);?>它的输出结果如下：Array ([DE] => Germany[IN] => India[ES] => Spain[US] => United States)

arsort(): 根据值按字母表顺序进行倒排。

<?php     $data = array("US" => "United States", "IN" => "India", "DE" => "Germany", "ES" => "Spain");    arsort($data);    print_r($data);?>Array ([US] => United States[ES] => Spain[IN] => India[DE] => Germany)