PHP中array_multisort与asort，arsort的用法

转载：http://my.oschina.net/zzqPHPer/blog/214149?fromerr=1rcJkRXO

文章来源：http://blog.sina.com.cn/s/blog_7eef675d0101fd9g.html

今天在做一个不涉及数据库的分页的时候，遇到一个按条件排序的问题，为此把解决的方案列在这里。。

PHP之所以被称之为高级语言，自然有她的妙用，就是它很多东西，早就有高手把它写好了，你只需要拿来用就行，不必自己去写方法。

所以很多人说PHP简单，其实我认为就是简单在这里，当然这只是我的个人观点。。

下面开始代码：

1、array_multisort的用法：

<?php
$arr1 = array(
    "0" => array("a" => 3, "b" => 20, "c" => 2, "d" => 6),
    "1" => array("a" => 3, "b" => 2, "c" => 2, "d" => 6),
    "2" => array("a" => 3, "b" => 22, "c" => 2, "d" => 6),
    "3" => array("a" => 3, "b" => 25, "c" => 2, "d" => 6),
    "4" => array("a" => 3, "b" => 28, "c" => 2, "d" => 6),
    "5" => array("a" => 3, "b" => 3, "c" => 2, "d" => 6),
);
 
$arr2 = array(
    "e1" => array("a" => 3, "b" => 20, "c" => 2, "d" => 6),
    "e2" => array("a" => 3, "b" => 2, "c" => 2, "d" => 6),
    "e3" => array("a" => 3, "b" => 22, "c" => 2, "d" => 6),
    "e4" => array("a" => 3, "b" => 25, "c" => 2, "d" => 6),
    "e5" => array("a" => 3, "b" => 28, "c" => 2, "d" => 6),
    "e6" => array("a" => 3, "b" => 3, "c" => 2, "d" => 6),
);
 
//提取列数组；
foreach ($arr1 as $key => $val) {
    $tmp[$key] = $val["b"];
}
 
array_multisort($tmp,SORT_DESC,$arr1);
echo "<pre>";
    print_r($arr1);
echo "</pre>";
 
array_multisort($tmp,SORT_DESC,$arr2);
echo "<pre>";
    print_r($arr2);
echo "</pre>";
 
?>

2、array_sort的用法：

<?php
$arr1 = array(
    "0" => array("a" => 3, "b" => 20, "c" => 2, "d" => 6),
    "1" => array("a" => 3, "b" => 2, "c" => 2, "d" => 6),
    "2" => array("a" => 3, "b" => 22, "c" => 2, "d" => 6),
    "3" => array("a" => 3, "b" => 25, "c" => 2, "d" => 6),
    "4" => array("a" => 3, "b" => 28, "c" => 2, "d" => 6),
    "5" => array("a" => 3, "b" => 3, "c" => 2, "d" => 6),
);
 
$arr2 = array(
    "e1" => array("a" => 3, "b" => 20, "c" => 2, "d" => 6),
    "e2" => array("a" => 3, "b" => 2, "c" => 2, "d" => 6),
    "e3" => array("a" => 3, "b" => 22, "c" => 2, "d" => 6),
    "e4" => array("a" => 3, "b" => 25, "c" => 2, "d" => 6),
    "e5" => array("a" => 3, "b" => 28, "c" => 2, "d" => 6),
    "e6" => array("a" => 3, "b" => 3, "c" => 2, "d" => 6),
);
 
function array_sort($array,$keys,$type="asc"){
    //$array为要排序的数组,$keys为要用来排序的键名,$type默认为升序排序
    $keysvalue = $new_array = array();
 
    //提取排序的列
    foreach ($array as $k=>$v){
        $keysvalue[$k] = $v[$keys];
    }
    if($type == "asc"){
        asort($keysvalue);//升序排列
    }else{
        arsort($keysvalue);//降序排列
    }
    //reset($keysvalue);
    foreach ($keysvalue as $k=>$v){
        $new_array[$k] = $array[$k];
    }
    return $new_array;
}
$arr = array_sort($arr1,"b","desc"); //此处对数组进行降序排列

思路总结：

总体的想法是这样的，要对一个多维数组按照某一个键值对排序，关键是先确定这个键值对的顺序，然后按照这个键值对的顺序去排列这个多维数组。

对于是数字索引的数组，第二种方法还是比较好的，因为它会保持数字索引，这个很好，而第一种就会把数字索引的数组重新建立数字索引；

对于是字符串索引的数组，两种方法都可以采用，完全看个人爱好。。