Detailed explanation of array multisort sorting principle_PHP tutorial

The above test code prompts that the array sizes are inconsistent in G:wwwtestindex.php on line 15

Look again

$data[] = array('volume' => 67, 'edition' => 2);
$data[] = array ('volume' => 86, 'edition' => 1);
$data[] = array('volume' => 85, 'edition' => 6);
$data [] = array('volume' => 98, 'edition' => 2);
$data[] = array('volume' => 86, 'edition' => 6);
$data[] = array('volume' => 67, 'edition' => 7, 3, 4,4);//The number of two-dimensional numbers is different
?>



$a = array(11,2,3 ,4,5,6);
$b = array(3,3,3,3,3,3);
//From the result, we can see the array(67,7,3, corresponding to 11, 4,4) appeared in the same order;
// Sort the data in descending order according to volume and in ascending order according to edition
// Use $data as the last parameter and sort by common key
array_multisort($a , $b, $data);
var_dump( $a,$data);
?>


From the above results we can know:
The array parameters must have the same one-dimensional number;
Then the corresponding position of each array
(Note that it is not the same key, but corresponding from the natural position, such as $a( 1=>4), corresponding to 4 of $b(99=>4), because their positions are all the first, not the corresponding relationship of key(1,99) ), The value in the corresponding position is like being threaded on equal bamboo poles. When one of the values ​​on it needs to be adjusted, it will cause other values ​​on the same "bamboo pole" to move vertically. .
Class:
$a $b $c
4=>7 8=>10 '999' => 0 9=>9 0=>1 999=>9
0=> 2 9=> 3 9999=>7
------------- --------
If the 7 and 9 of $a are swapped, it will also cause the 10 and 1 of $b to be swapped with the 0 and 9 of $c.
So the relationship is Like the three arrays above, those of the same color are on the same "front". If one of them changes, everyone must change positions together.

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