How to remove duplicates and the original one from a multidimensional array?

Question

How can I delete duplicates in a multidimensional array? I tried several answers found on stackoverflow but none of them works for me in an multi array. The closest answer i found was this:

How to delete duplicates in an array? But that only worked on a single-dimensional array.

For example i have this:

$array = array(
    [0] = array(
        [color] => red,
        [type] => color,
        [name] => color1
    )
    [1] = array(
        [color] => gray,
        [type] => color,
        [name] => color2
    )
    [2] = array(
        [color] => blue,
        [type] => color,
        [name] => color3
    )
    [3] = array(
        [color] => green,
        [type] => color,
        [name] => color4
    )
    [4] = array(
        [color] => black,
        [type] => color,
        [name] => color5
    )
    [3] = array(
        [color] => gray,
        [type] => color,
        [name] => color2
    )
    [4] = array(
        [color] => blue,
        [type] => color,
        [name] => color3
    )
)

How can i let it become this:?

$array = array(
    [0] = array(
        [color] => red,
        [type] => color,
        [name] => color1
    )
    [1] = array(
        [color] => gray,
        [type] => color,
        [name] => color2
    )
    [2] = array(
        [color] => blue,
        [type] => color,
        [name] => color3
    )
    [3] = array(
        [color] => green,
        [type] => color,
        [name] => color4
    )
    [4] = array(
        [color] => black,
        [type] => color,
        [name] => color5
    )
)

Your input and output doesn't make sense. How to you filter our "gray" for example? It's not clear. — scrowler, Aug 29 '16 at 04:54
I though it might be possible to filter out the duplicate row and the original. So array 1 matches array 3. Delete both rows. — Red, Aug 29 '16 at 05:09
Read awnser. It does what i asked. So 'not possible at all' kinda wierd awnser — Red, Aug 29 '16 at 05:32
@RichardMauritz it's possible(i know,i answered also), what i am saying that keys 3,4,3,4 that's not possible, because identical keys will over-write previous one — Alive to die - Anant, Aug 29 '16 at 05:34
You wrote errors in your code. Check this out: https://eval.in/630613 — Red, Aug 29 '16 at 05:44
@RichardMauritz check these links for further assessment (your initial array in which indexes over-writes previous values)https://eval.in/630605 and output after changing your initial array indexes:-https://eval.in/630585 — Alive to die - Anant, Aug 29 '16 at 08:14
Thanks for all the info. I get it now what u mean by all this. — Red, Aug 29 '16 at 08:23

score 3 · Accepted Answer · answered Aug 29 '16 at 04:55

3

Well, this is a very poor answer but it appears you want UNIQUE data, here's some very bad code to solve this.

$array2 = array();
foreach ($array as $val) 
{
  @$array2[$val['color']]++;
}
foreach ($array as $key=>$val) 
{
  if ($array2[$val['color']] >1)
   unset($array[$key]);
}

The @ is there to prevent php from throwing an error. or you can write more code to predefine $array2 but this does work.

answered Aug 29 '16 at 04:55

Forbs

1,256
1
7
9

1

why not just type it ^_^, its just one line to initialize – Kevin Aug 29 '16 at 04:57
you can do it on 1 line? I have to create a 3rd foreach loop for it to be right. – Forbs Aug 29 '16 at 04:58
Thanks, this did exacly what i wanted. Just curious, is there also a one line solution? – Red Aug 29 '16 at 05:21
@Forbs his input array keys are identical. i don't think it's correct – Alive to die - Anant Aug 29 '16 at 05:27

Kevin · Answer 2 · 2016-08-29T05:10:28.633

1

You could get the count of colors first, so that you could distinguish which will be removed and will be kept.

Then, after that, you'll know which color to keep.

To get the count just use array_count_values to get which to keep. Then finally, filter:

$a = array_count_values(array_column($array, 'color'));
$new_array = array_filter($array, function($e) use($a) {
    return $a[$e['color']] === 1; // filter count equal to 1
});

This uses array_column which may not be available on your environment, you may use this line as an alternative:

$a = array_count_values(array_map(function($e){ return $e['color']; }, $array));

edited Aug 29 '16 at 05:10

answered Aug 29 '16 at 05:05

Kevin

41,694
12
53
70

Thanks for the awnser. However, the accepted awnser worked like a charm for me ;) – Red Aug 29 '16 at 05:22
@RichardMauritz sure no prob – Kevin Aug 29 '16 at 05:25

score 0 · Answer 3 · answered Aug 29 '16 at 04:59

Assume your array is this

$array = array(
    '0' => array(
        'color' => 'red',
        'type' => 'color',
        'name' => 'color1'
    ),
    '1' => array(
        'color' => 'gray',
        'type' => 'color',
        'name' => 'color2'
    ),
    '2' => array(
        'color' => 'blue',
        'type' => 'color',
        'name' => 'color3'
    ),
    '3' => array(
        'color' => 'green',
        'type' => 'color',
        'name' => 'color4'
    ),
    '4' => array(
        'color' => 'black',
        'type' => 'color',
        'name' => 'color5'
    ),
    '5' => array(
        'color' => 'gray',
        'type' => 'color',
        'name' => 'color2'
    ),
    '6' => array(
        'color' => 'blue',
        'type' => 'color',
        'name' => 'color3'
    )
);

Code

$input = array_map("unserialize", array_unique(array_map("serialize", $array)));
echo ' <pre>';
print_r($input);

Output

Array
(
    [0] => Array
        (
            [color] => red
            [type] => color
            [name] => color1
        )

    [1] => Array
        (
            [color] => gray
            [type] => color
            [name] => color2
        )

    [2] => Array
        (
            [color] => blue
            [type] => color
            [name] => color3
        )

    [3] => Array
        (
            [color] => green
            [type] => color
            [name] => color4
        )

    [4] => Array
        (
            [color] => black
            [type] => color
            [name] => color5
        )

)

the OP wants to take out (don't include) array values that has duplicates, check out the expected out, and the first answer is already correct — Kevin, Aug 29 '16 at 05:01

How to remove duplicates and the original one from a multidimensional array?

3 Answers3