Cannot reverse a multidimensional array

Question

I have an array with this structure:

[
    {
        "id": "2644688"
    },
    {
        "id": "2644689"
    }
]

I'm trying to reverse it using array_reverse:

$reversed = array_reverse($result, true);
return $response->withJson($reversed);

but I get:

{
 "0": {
       "id": "2644688"
 },
 "1": {
       "id": "2644689"
 }
}

the order is the same, the function array_reverse just added the numerical indexes, I did something wrong?

I've tried the same but result is as you want it not as you showed here. — Lovepreet Singh, Jul 06 '18 at 08:18
This is what I got: `{"1":{"id":"2644689"},"0":{"id":"2644688"}}` — Lovepreet Singh, Jul 06 '18 at 08:20
@LovepreetSingh are you sure? I get the same output wrote in question — Charanoglu, Jul 06 '18 at 08:22
but wait, I didn't used json_encode, why my question was marked as json_encode duplicate? — Charanoglu, Jul 06 '18 at 08:23
The code I've tried: `$array = json_decode($json, true); print_r(json_encode(array_reverse($array)));`. — Lovepreet Singh, Jul 06 '18 at 08:23
@LovepreetSingh but you have passed a json, I have an array first — Charanoglu, Jul 06 '18 at 08:25
Let us [continue this discussion in chat](https://chat.stackoverflow.com/rooms/174483/discussion-between-charanoglu-and-lovepreet-singh). — Charanoglu, Jul 06 '18 at 08:27
I tried this on a PHP testbed and it worked fine, please see [my example](https://tehplayground.com/8HrN1wOxusXRoqS9) — Can O' Spam, Jul 06 '18 at 08:29

score 1 · Answer 1 · answered Jul 06 '18 at 08:37

You should not pass true in the second argument of array_reverse.

Try replacing your code to:

$reversed = array_reverse($result, false);

Or just:

$reversed = array_reverse($result);

The second argument is preserving original array keys. The problem with that is that JavaScript will change it's order according to the keys, so the output of the json will be:

{"1":{"id":"2644689"},"0":{"id":"2644688"}}

And JavaScript will change the order to 0,1.

score 1 · Accepted Answer · answered Jul 06 '18 at 08:39

According to array_reverse documentation. Second parameter, if set to TRUE numeric keys are preserved. Non-numeric keys are not affected by this setting and will always be preserved.

So try removing true as second parameter.

$reversed = array_reverse($result);
return $response->withJson($reversed);

Cannot reverse a multidimensional array

2 Answers2