PHP中array_multisort與asort，arsort的用法

文章來源：http://blog.sina.com.cn/s/blog_7eef675d0101fd9g.html

今天在作一個不涉及數據庫的分頁的時候，遇到一個按條件排序的問題，爲此把解決的方案列在這裏。。

PHP之因此被稱之爲高級語言，天然有她的妙用，就是它不少東西，早就有高手把它寫好了，你只須要拿來用就行，沒必要本身去寫方法。

因此不少人說PHP簡單，其實我認爲就是簡單在這裏，固然這只是個人我的觀點。。

下面開始代碼：

一、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),
);

//提取列數組；
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>";

?>

二、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爲要排序的數組,$keys爲要用來排序的鍵名,$type默認爲升序排序
    $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'); //此處對數組進行降序排列

思路總結：

整體的想法是這樣的，要對一個多維數組按照某一個鍵值對排序，關鍵是先肯定這個鍵值對的順序，而後按照這個鍵值對的順序去排列這個多維數組。

對因而數字索引的數組，第二種方法仍是比較好的，由於它會保持數字索引，這個很好，而第一種就會把數字索引的數組從新創建數字索引；

對因而字符串索引的數組，兩種方法均可以採用，徹底看我的愛好。。