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HomeBackend DevelopmentPHP Tutorialphp根据分类合并数组的方法实例详解_PHP

最简单的数组合并我们只要使用array_merge即可
array_merge()将两个或多个数组的单元合并起来,一个数组中的值附加在前一个数组的后面。返回作为结果的数组。
数组键名为数字键名时,要合并的两个数组中有同名数字KEY的时候,使用array_merge()不会覆盖掉原来的值,而使用“+”合并数组则会把最先出现的值作为最终结果返回,而把后面的数组拥有相同键名的那些值“抛弃”掉(注意:不是覆盖而是保留最先出现的那个值)。例子:
复制代码 代码如下:
  $array1 = array(1=>'0');
  $array2 = array(1=> "data");
     $result1 = $array2 + $array1;/*结果为$array2的值*/
    print_r($result);
    $result = $array1 + $array2 ;/*结果为$array1的值*/
    print_r($result);
    $result3 = array_merge($array2,$array1);/*结果为$array2和$array1的值,键名被重新分配*/
    print_r($result3);
    $result4 = array_merge($array1,$array2);/*结果为$array1和$array2的值,键名被重新分配*/
    print_r($result4);

输出结果为:
Array ( [1] => data )
Array ( [1] => 0 )
Array (
[0] => data
[1] => 0
)
Array
(
[0] => 0
[1] => data
)

2.当相同数组键名为字符时,“+”运算符与键名为数字时一样,但array_merge()此时会覆盖掉前面相同键名的值。
例子:
复制代码 代码如下:
 $array1 = array('asd'=>'0');
  $array2 = array('asd' => "data");
  $result1 = $array2 + $array1;/*结果为$array2的值*/
  print_r($result);
    $result = $array1 + $array2 ;/*结果为$array1的值*/
    print_r($result);
    $result3 = array_merge($array2,$array1);/*结果为$array1*/
    print_r($result3);
    $result4 = array_merge($array1,$array2);/*结果为$array2*/
    print_r($result4);

输出结果为:
Array ( [asd] => data )
Array ( [asd] => 0 )
Array ( [asd] => 0 )
Array ( [asd] => data )

讲了这么多费话,下面才是我要给各位朋友介绍的
根据分类字段进行数组重组
 复制代码 代码如下:
//需要重组的数组
$arrar=array();
$array[]=array('ItemID' => 110126866896,'CategoryID'=>111);
$array[]=array('ItemID' => 120126866896,'CategoryID'=>112);
$array[]=array('ItemID' => 130126866896,'CategoryID'=>113);
$array[]=array('ItemID' => 140126866896,'CategoryID'=>114);
$array[]=array('ItemID' => 150126866896,'CategoryID'=>115);
$array[]=array('ItemID' => 160126866896,'CategoryID'=>116);
$array[]=array('ItemID' => 170126866896,'CategoryID'=>117);
$array[]=array('ItemID' => 118126866896,'CategoryID'=>111);
$array[]=array('ItemID' => 121126866896,'CategoryID'=>112);
$array[]=array('ItemID' => 132126866896,'CategoryID'=>113);
$array[]=array('ItemID' => 143126866896,'CategoryID'=>114);
$array[]=array('ItemID' => 154126866896,'CategoryID'=>115);
$array[]=array('ItemID' => 165126866896,'CategoryID'=>116);
$array[]=array('ItemID' => 176126866896,'CategoryID'=>117);
//数组根据分类进行重组
$newArray=array();
foreach($array as $val){
    $newArray[$val['CategoryID']][]=$val;
}

//删除原始数组释放空间
$array=null;
unset($array);

print_r($newArray);

?>
 

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