php remove duplicates from multidimensional array by value [duplicate]

Question

I would like to remove duplicates by value as you can see from the list_title. I know there are several questions and answers to this but their solution doesn't work for me.

Here is what I've tried:

$uniqueArray = array_map("unserialize", array_unique(array_map("serialize", $notify)));

Result:

Array
(
[0] => Array
    (
        [list_id] => 86
        [list_reference] => 130948
        [list_title] => Offer:  apartment 2+kk 
        [list_city] => Prague
        [list_date] => 2017-03-03 11:20:35
        [list_status] => 0
        [list_creator] => Company A
        [list_price] => 30000
        [list_furniture] => ["1","0","0"]
        [list_accommodation] => flat
    )

[1] => Array
    (
        [list_id] => 87
        [list_reference] => 130947
        [list_title] => Offer:  apartment 2+kk 
        [list_date] => 2017-03-03 11:20:35
        [list_status] => 0
        [list_creator] => Company B
        [list_price] => 30000
        [list_furniture] => ["1","0","0"]
        [list_accommodation] => flat
    )

[2] => Array ...

Expected result should be one of those because of the title:

Array
(
[0] => Array
(
    [list_id] => 86
    [list_reference] => 130948
    [list_title] => Offer:  apartment 2+kk 
    [list_city] => Prague
    [list_date] => 2017-03-03 11:20:35
    [list_status] => 0
    [list_creator] => Company A
    [list_price] => 30000
    [list_furniture] => ["1","0","0"]
    [list_accommodation] => flat
)

Answer 1

So basically you want to remove duplicates by 'list_title' column. Let's assume we keep the first occurrence of this title. Then you can use a couple of standard functions to achieve this:

// Reverse array, so the first occurrence kept.
$data = array_reverse($data);

$result = array_reverse( // Reverse array to the initial order.
    array_values( // Get rid of string keys (make array indexed again).
        array_combine( // Create array taking keys from column and values from the base array.
            array_column($data, 'list_title'), 
            $data
        )
    )
);

Here is working demo.

UPDATE:

Based on @mickmackusa comment, the code can be simplified to:

$result = array_reverse(array_values(array_column(
    array_reverse($data),
    null,
    'list_title'
)));

This is described in the docs regarding column_key parameter specs:

It may also be NULL to return complete arrays or objects (this is useful together with index_key to reindex the array).

Answer 2

Thanks everyone, sometimes over-thinking can affect common sense.

I simply solved it from MYSQL query with something like:

 GROUP BY list_title ORDER BY list_date