PHP array merge and re-merge according to classification_PHP tutorial

There are many methods for simple array merging in php, but my requirement today is to re-merge the arrays based on the array ID, and to operate based on classification.

For the simplest array merging, we only need to use array_merge

array_merge() merges the cells of two or more arrays, and the values ​​in one array are appended to the previous array. Returns the resulting array.

When the array key name is a numeric key name, and the two arrays to be merged have numeric KEYs with the same name, using array_merge() will not overwrite the original value, while using "+" to merge the arrays will replace the first The value that appears is returned as the final result, and those values ​​in subsequent arrays with the same key name are "discarded" (note: the value that appears first is not overwritten but retained). Example:

The code is as follows

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代码如下

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$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 )

　$array1 = array(1=>'0');

​$array2 = array(1=> "data");
​​ $result1 = $array2 + $array1;/*The result is the value of $array2*/

​print_r($result);

代码如下

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$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 )

​ $result = $array1 + $array2 ;/*The result is the value of $array1*/ ​print_r($result); ​ $result3 = array_merge($array2,$array1);/*The result is the value of $array2 and $array1, and the key name is reassigned*/ ​ print_r($result3); $result4 = array_merge($array1,$array2);/*The result is the value of $array1 and $array2, and the key name is reassigned*/ ​ print_r($result4); The output result is: Array ( [1] => data ) Array ( [1] => 0 ) Array ( [0] => data [1] => 0 ) Array ( [0] => 0 [1] => data )

2. When the same array key name is a character, the "+" operator is the same as when the key name is a number, but array_merge() will overwrite the previous value of the same key name. Example:

The code is as follows

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$array1 = array('asd'=>'0'); ​$array2 = array('asd' => "data"); $result1 = $array2 + $array1;/*The result is the value of $array2*/ print_r($result); ​ $result = $array1 + $array2 ;/*The result is the value of $array1*/ ​print_r($result); ​ $result3 = array_merge($array2,$array1);/*The result is $array1*/ ​ print_r($result3); ​ $result4 = array_merge($array1,$array2);/*The result is $array2*/ ​ print_r($result4); The output result is: Array ( [asd] => data ) Array ( [asd] => 0 ) Array ( [asd] => 0 ) Array ( [asd] => data )

After talking so much, here is what I want to introduce to my friends

Example.

Array reorganization based on classification fields

The code is as follows

代码如下

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//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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//Array that needs to be reorganized
$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);
//The array is reorganized according to classification
$newArray=array();
foreach($array as $val){
$newArray[$val['CategoryID']][]=$val;
}

//Delete the original array to free up space
$array=null;
unset($array);

print_r($newArray);

?>

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There are many methods for simple array merging in php, but my requirement today is to re-merge it based on the array ID. Merging arrays is based on classification. The simplest array merge I have...