php基础篇-二维数组排序 array_multisort

对2维数组或者多维数组排序是常见的问题，在php中我们有个专门的多维数组排序函数，下面简单介绍下：

array_multisort(array1,sorting order, sorting type,array2,array3..）是对多个数组或多维数组进行排序的函数。

array1	必需。规定输入的数组。
sorting order	可选。规定排列顺序。可能的值是 SORT_ASC 和 SORT_DESC。
sorting type	可选。规定排序类型。可能的值是SORT_REGULAR、SORT_NUMERIC和SORT_STRING。
array2	可选。规定输入的数组。
array3	可选。规定输入的数组。

参数中的数组被当成一个表的列并以行来进行排序 - 这类似 SQL 的 ORDER BY 子句的功能。第一个数组是要排序的主要数组。数组中的行（值）比较为相同的话，就会按照下一个输入数组中相应值的大小进行排序，依此类推。

第一个参数是数组，随后的每一个参数可能是数组，也可能是下面的排序顺序标志（排序标志用于更改默认的排列顺序）之一：

• SORT_ASC - 默认，按升序排列。(A-Z)
• SORT_DESC - 按降序排列。(Z-A)

随后可以指定排序的类型：

• SORT_REGULAR - 默认。将每一项按常规顺序排列。
• SORT_NUMERIC - 将每一项按数字顺序排列。
• SORT_STRING - 将每一项按字母顺序排列

<?php

	function my_sort($arrays,$sort_key,$sort_order=SORT_ASC,$sort_type=SORT_NUMERIC ){ 
		if(is_array($arrays)){ 
			foreach ($arrays as $array){ 
				if(is_array($array)){ 
					$key_arrays[] = $array[$sort_key]; 
				}else{ 
					return false; 
				} 
			} 
		}else{ 
			return false; 
		}
		array_multisort($key_arrays,$sort_order,$sort_type,$arrays); 
		return $arrays; 
	}

	$person =  array(
					array("id"=>1,"name"=>"fj","weight"=>100,"height"=>180),
					array("id"=>2,"name"=>"tom","weight"=>53,"height"=>150),
					array("id"=>3,"name"=>"jerry","weight"=>120,"height"=>156),
					array("id"=>4,"name"=>"bill","weight"=>110,"height"=>190),
					array("id"=>5,"name"=>"linken","weight"=>80,"height"=>200),
					array("id"=>6,"name"=>"madana","weight"=>95,"height"=>110),
					array("id"=>7,"name"=>"jordan","weight"=>70,"height"=>170)
				);
	
	var_dump($person);
	
	$person = my_sort($person,"name",SORT_ASC,SORT_STRING);

	var_dump($person);
	
	$person = my_sort($person,"weight");

	var_dump($person);
?>

结果如下：

array (size=7)
  0 => 
    array (size=4)
      "id" =>  1
      "name" =>  "fj" (length=2)
      "weight" =>  100
      "height" =>  180
  1 => 
    array (size=4)
      "id" =>  2
      "name" =>  "tom" (length=3)
      "weight" =>  53
      "height" =>  150
  2 => 
    array (size=4)
      "id" =>  3
      "name" =>  "jerry" (length=5)
      "weight" =>  120
      "height" =>  156
  3 => 
    array (size=4)
      "id" =>  4
      "name" =>  "bill" (length=4)
      "weight" =>  110
      "height" =>  190
  4 => 
    array (size=4)
      "id" =>  5
      "name" =>  "linken" (length=6)
      "weight" =>  80
      "height" =>  200
  5 => 
    array (size=4)
      "id" =>  6
      "name" =>  "madana" (length=6)
      "weight" =>  95
      "height" =>  110
  6 => 
    array (size=4)
      "id" =>  7
      "name" =>  "jordan" (length=6)
      "weight" =>  70
      "height" =>  170

array (size=7)
  0 => 
    array (size=4)
      "id" =>  4
      "name" =>  "bill" (length=4)
      "weight" =>  110
      "height" =>  190
  1 => 
    array (size=4)
      "id" =>  1
      "name" =>  "fj" (length=2)
      "weight" =>  100
      "height" =>  180
  2 => 
    array (size=4)
      "id" =>  3
      "name" =>  "jerry" (length=5)
      "weight" =>  120
      "height" =>  156
  3 => 
    array (size=4)
      "id" =>  7
      "name" =>  "jordan" (length=6)
      "weight" =>  70
      "height" =>  170
  4 => 
    array (size=4)
      "id" =>  5
      "name" =>  "linken" (length=6)
      "weight" =>  80
      "height" =>  200
  5 => 
    array (size=4)
      "id" =>  6
      "name" =>  "madana" (length=6)
      "weight" =>  95
      "height" =>  110
  6 => 
    array (size=4)
      "id" =>  2
      "name" =>  "tom" (length=3)
      "weight" =>  53
      "height" =>  150

array (size=7)
  0 => 
    array (size=4)
      "id" =>  2
      "name" =>  "tom" (length=3)
      "weight" =>  53
      "height" =>  150
  1 => 
    array (size=4)
      "id" =>  7
      "name" =>  "jordan" (length=6)
      "weight" =>  70
      "height" =>  170
  2 => 
    array (size=4)
      "id" =>  5
      "name" =>  "linken" (length=6)
      "weight" =>  80
      "height" =>  200
  3 => 
    array (size=4)
      "id" =>  6
      "name" =>  "madana" (length=6)
      "weight" =>  95
      "height" =>  110
  4 => 
    array (size=4)
      "id" =>  1
      "name" =>  "fj" (length=2)
      "weight" =>  100
      "height" =>  180
  5 => 
    array (size=4)
      "id" =>  4
      "name" =>  "bill" (length=4)
      "weight" =>  110
      "height" =>  190
  6 => 
    array (size=4)
      "id" =>  3
      "name" =>  "jerry" (length=5)
      "weight" =>  120
      "height" =>  156

这里的重点就是，先把要排序的key存到一个一维数组中，然后就可以使用array_multisort()这个函数，将数组按照key进行排序了，当然，这里的排序你完全可以不适用array_multisort()这个函数，仅仅通过foreach遍历也能达到这个效果，但是既然php开发者给我们提供了更好的办法，我们就可以省去不必要的麻烦了。