PHP-数组

<?php

$array[] = array("age"=>25, "name"=>"li", "aa"=>22);
$array[] = array("age"=>24,"name"=>"ai", "aa"=>24);
$array[] = array("age"=>23,"name"=>"ci", "aa"=>23);
$array[] = array("age"=>22,"name"=>"di", "aa"=>25);

foreach ($array as $key=>$value){

}

foreach ($array as $key => $value){
    $age[$key] = $value['age'];
}

array_multisort($age,SORT_NUMERIC,SORT_ASC,$array);


print_r($age);


重点：$age是引用

function array_multisort (array &$arr, $arg = null, $arg = null, $_ = null) {}

 

function in_array ($needle, array $haystack, $strict = false) {}

foreach($array as $key=>$value)

重点：比较$value是否存在