How to order the arrays in the reverse order of their creation with php?-CodePudding

I see that there is a lot of documentation for ordering array, but all I find is for ordering existing values within an array.

In my case, I need to sort the array themselves, within a meta that includes multiple array. And I want to order them in the reverse order of their creation.

Example:


$datacomments = get_post_meta($product_id, 'propina5', false); 

echo print_r($datacomments);

//Result:

Array ( [0] => Array ( [date] => 30-11-2021 13:38 [id] => 2 [rating] => 4 [comment] => bala bla bla bla bla [perce] => 10 ) 

[1] => Array ( [date] => 30-11-2021 13:38 [id] => 2 [rating] => 4 [comment] => bala bla bla bla bla [perce] => 10 ) 

[2] => Array ( [date] => 30-11-2021 13:40 [id] => 2 [rating] => 5 [comment] => bla bla bla bla [perce] => 10 ) 

[3] => Array ( [date] => 30-11-2021 13:41 [id] => 2 [rating] => 3 [comment] => bla bla bla bla bla [perce] => 5 ) ) 1

I have 3 arrays the [0], [1], [2] and the [3] ordered by default as they were created. But I need to exactly order them in reverse order since my intention is that the most recent ones appear first and not the other way around.

Well I can't find documentation or can't see if it's there in either official php or w3school, where I usually look for how to sort in this case.

Any suggestion? From already thank you very much.

CodePudding user response：

$reversed = array_reverse($input);

Docs: https://www.php.net/manual/en/function.array-reverse.php

If this array was the result of an query from database, you can use ORDER BY syntax from sql to get exactly you need.

CodePudding user response：

This will sort by the date value of each subarray in descending order:

$arr = [
    [ 'date' => '29-11-2021 22:32', 'id' => 2, 'rating' => 4, 'comment' => 'bla bla bla', 'perce' => 10 ],
    [ 'date' => '29-11-2021 22:35', 'id' => 8, 'rating' => 4, 'comment' => 'bla bla bla', 'perce' => 10 ],
    [ 'date' => '29-11-2021 22:45', 'id' => 6, 'rating' => 4, 'comment' => 'bla bla bla', 'perce' => 10 ]
];

usort($arr, static fn(array $arr1, array $arr2): int => -($arr1['date'] <=> $arr2['date']));

The same code would also work for DateTime objects:

$arr = [
    [ 'date' => new DateTime('29-11-2021 22:32'), 'id' => 2, 'rating' => 4, 'comment' => 'bla bla bla', 'perce' => 10 ],
    [ 'date' => new DateTime('29-11-2021 22:35'), 'id' => 8, 'rating' => 4, 'comment' => 'bla bla bla', 'perce' => 10 ],
    [ 'date' => new DateTime('29-11-2021 22:45'), 'id' => 6, 'rating' => 4, 'comment' => 'bla bla bla', 'perce' => 10 ]
];

usort($arr, static fn(array $arr1, array $arr2): int => -($arr1['date'] <=> $arr2['date']));