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."
";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($arr);echo "
=================
";print_r($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 ) )