PHP中二维数组排序,可以使用PHP内置函数uasort()
示例一:
使用用户自定义的比较函数对数组中的值进行排序并保持索引关联
回调函数如下:注意回调函数的返回值是负数或者是false的时候,表示回调函数的第一个参数在前,第二个参数在后排列
$person = array( array('num'=>'001','id'=>6,'name'=>'zhangsan','age'=>21), array('num'=>'001','id'=>7,'name'=>'ahangsan','age'=>23), array('num'=>'003','id'=>1,'name'=>'bhangsan','age'=>23), array('num'=>'001','id'=>3,'name'=>'dhangsan','age'=>23), ); //负数或者false表示第一个参数应该在前 function sort_by_name($x,$y){ return strcasecmp($x['name'],$y['name']); }
使用如下:
uasort($person,'sort_by_name');
下面给出一个二维数组排序的方法,供参考和面试使用:
//$array 要排序的数组 //$row 排序依据列 //$type 排序类型[asc or desc] //return 排好序的数组 function array_sort($array,$row,$type){ $array_temp = array(); foreach($array as $v){ $array_temp[$v[$row]] = $v; } if($type == 'asc'){ ksort($array_temp); }elseif($type='desc'){ krsort($array_temp); }else{ } return $array_temp; }
示例二:
一维数组排序可以使用asort、ksort等一些方法进程排序,相对来说比较简单。二维数组的排序怎么实现呢?使用array_multisort和usort可以实现
例如像下面的数组:
代码如下:
$users = array( array('name' => 'tom', 'age' => 20) , array('name' => 'anny', 'age' => 18) , array('name' => 'jack', 'age' => 22) );
希望能按照age从小到大进行排序。笔者整理了两个方法出来,分享给大家。
1、使用array_multisort
使用这个方法,会比较麻烦些,要将age提取出来存储到一维数组里,然后按照age升序排列。具体代码如下:
代码如下:
$ages = array(); foreach ($users as $user) { $ages[] = $user['age']; } array_multisort($ages, SORT_ASC, $users);
执行后,$users就是排序好的数组了,可以打印出来看看。如果需要先按年龄升序排列,再按照名称升序排列,方法同上,就是多提取一个名称数组出来,最后的排序方法这样调用:
代码如下:
array_multisort($ages, SORT_ASC, $names, SORT_ASC, $users);
2、使用usort
使用这个方法最大的好处就是可以自定义一些比较复杂的排序方法。例如按照名称的长度降序排列:
代码如下:
usort($users, function($a, $b) { $al = strlen($a['name']); $bl = strlen($b['name']); if ($al == $bl) return 0; return ($al > $bl) ? -1 : 1; });
这里使用了匿名函数,如果有需要也可以单独提取出来。其中$a, $b可以理解为$users数组下的元素,可以直接索引name值,并计算长度,而后比较长度就可以了。
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这里顺便说一下PHP排序的几个函数
sort 对数组排序一般适用于一维索引数组,不会保持索引
rsort 对数组逆向排序 和sort用法一致
asort 对数组进行排序并保持索引关系对值进行排序,一般适用于一维数组,保持索引关系
arsort 对数组进行逆向排序并保持索引关系和asort用法一致
ksort 对数组按照键名排序
krsort 对数组按照键名逆向排序

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