<?php

/*数组排序函数

 * sort natsort shuffle natcasesoft array_multisort

 */

//sort() 对数组元素进行递增的排序，

/*$arr=array(10,2,3,40,5);

sort($arr);

print_r($arr);//输出：Array ( [0] => 2 [1] => 3 [2] => 5 [3] => 10 [4] => 40 )*/

/*$arr2=array('class1','class2','class12','class32','class21');

sort($arr2);

print_r($arr2);//输出：Array ( [0] => class1 [1] => class12 [2] => class2 [3] => class21 [4] => class32 )*/

//natsort() 通过自然排序对数组进行排序。保留原数组索引

/*$arr2=array('class1','class2','class12','class32','class21');

natsort($arr2);

print_r($arr2);//输出：Array ( [0] => class1 [1] => class2 [2] => class12 [4] => class21 [3] => class32 )*/

//不区分字符大小写进行排序：

/*$arr=array('a','b','c','d','A','D','C','B');

natcasesort($arr);

print_r($arr);//输出：Array ( [0] => a [4] => A [1] => b [7] => B [2] => c [6] => C [3] => d [5] => D )*/

//shuffle()随机对数组进行排序  生成新的数组，原有键名删除

/*$arr3=array(1,2,3);

shuffle($arr3);

print_r($arr3);//输出：随机输出，原有键名删除*/

/*$arr3=array(1,2,3);

shuffle($arr3);

foreach ($arr3 as $k=>$v):

    echo $k."=>".$v."<br/>";

endforeach;*/

//array_multisort() 对多个数组或多维数组进行排序，

/*$arr=array(2,1,3,1);

$arr2=array(6,5,4,7);

array_multisort($arr,SORT_ASC,$arr2,SORT_DESC);

print_r($arr);

echo "<br/>=================<br/>";

print_r($arr2);*/

/*

Array ( [0] => 1 [1] => 1 [2] => 2 [3] => 3 )

=================

Array ( [0] => 7 [1] => 5 [2] => 6 [3] => 4 )

 * */

$arr=array(

    array(2,1,3,1),

    array(6,5,4,7)

);

array_multisort($arr[0],SORT_ASC,$arr[1],SORT_DESC);

print_r($arr);

//输出：Array ( [0] => Array ( [0] => 1 [1] => 1 [2] => 2 [3] => 3 ) [1] => Array ( [0] => 7 [1] => 5 [2] => 6 [3] => 4 ) )