Remove Duplicate Nested Arrays From Multidimenssional Array By Nested Array Key

Question

I am trying to create an array where I need to filter with a certain key (fileid) so that it returns only unique keys for parent array. Here is what I have..

Array
(
    [ABCD] => Array
        (
            [0] => Array
                (
                    [fileid] => 5454554
                    [filename] => myfile1.txt
                )

            [1] => Array
                (
                    [fileid] => 5454954
                    [filename] => myfile2.txt
                )

            [2] => Array
                (
                    [fileid] => 5454554
                    [filename] => myfile1.txt
                )

        )

    [EFGH] => Array
        (
            [0] => Array
                (
                    [fileid] => 5429654
                    [filename] => myfile2.txt
                )

            [1] => Array
                (
                    [fileid] => 5433954
                    [filename] => myfile2.txt
                )

            [2] => Array
                (
                    [fileid] => 5429654
                    [filename] => myfile1.txt
                )

        )

)

The first keys (ABCD and EFGH) are File Owner IDs. The nested arrays contains the File ID and the FIle Name. I need to filter it so that every duplicate nested array (having same fileid) is removed.

I tried this this and this and many other solutions found on the web. But no luck. I also tried

$result =  array_map("unserialize", array_unique(array_map("serialize", $file_array)));

No Luck again. Can someone please guide me to the right direction?

Thanks in advance.

RiggsFolly · Accepted Answer · 2023-03-03 17:02:20Z

A simple couple of loops where you remember the fileid's that you have seen in the inner array. If you see a fileid twice, you unset that occurance of the array. Note using &$owners in the outer loop so you can actually remove an occurance from within the foreach loop

$input = [  'ABCD' => [
                    ['fileid' => 5454554, 'filename' => 'myfile1.txt'],
                    ['fileid' => 5454954, 'filename' => 'myfile2.txt'],
                    ['fileid' => 5454554, 'filename' => 'myfile1.txt']
                    ],
            'EFGH' => [
                    ['fileid' => 5429654, 'filename' => 'myfile2.txt'],
                    ['fileid' => 5433954, 'filename' => 'myfile2.txt'],
                    ['fileid' => 5429654, 'filename' => 'myfile1.txt']
            ]
];
foreach ($input as &$owners){
    $ids = [];
    foreach($owners as $i=>$file){
        if ( in_array($file['fileid'], $ids) ){
            unset($owners[$i]);
        } else {
            $ids[] = $file['fileid'];
        }
    }
}
print_r($input);

RESULT

Array
(
    [ABCD] => Array
        (
            [0] => Array
                ( [fileid] => 5454554, [filename] => myfile1.txt )

            [1] => Array
                ( [fileid] => 5454954, [filename] => myfile2.txt )
        )
    [EFGH] => Array
        (
            [0] => Array
                ( [fileid] => 5429654, [filename] => myfile2.txt )

            [1] => Array
                ( [fileid] => 5433954,  [filename] => myfile2.txt )
        )
)

OR

Build a new array containing only the non duplicated files

$input = [  'ABCD' => [
                    ['fileid' => 5454554, 'filename' => 'myfile1.txt'],
                    ['fileid' => 5454954, 'filename' => 'myfile2.txt'],
                    ['fileid' => 5454554, 'filename' => 'myfile1.txt']
                    ],
            'EFGH' => [
                    ['fileid' => 5429654, 'filename' => 'myfile2.txt'],
                    ['fileid' => 5433954, 'filename' => 'myfile2.txt'],
                    ['fileid' => 5429654, 'filename' => 'myfile1.txt']
            ]
];
$new = [];
foreach ($input as $owner => $files){
    $t = [];
    $ids = [];

    foreach($files as $i=>$file){
        if ( ! in_array($file['fileid'], $ids) ){
            $t[] = $file;
            $ids[] = $file['fileid'];
        }
    }
    $new[$owner] = $t;
}
print_r($new);

MC57 · Accepted Answer · 2023-03-03 15:49:42Z

1

You can use a combination of array_map and array_filter like so:

array_map(
    function($arr) {
        $exists = [];
        return array_values(
            array_filter(
                $arr,
                function($arr1) use (&$exists) {
                    if (isset($exists[$arr1['fileid']])) {
                        return false;
                    }
                    $exists[$arr1['fileid']] = true;
                    return true;
                }
            )
        );
    },
    $file_array,
);

Note: I used array_values to ensure the resultant array has consecutive numerical keys. If you want to keep the original numerical keys then it can be omitted.

edited Mar 3, 2023 at 15:49

answered Mar 3, 2023 at 15:34

MC57

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3 Comments

Abhik Over a year ago

Giving me an error :( PHP Parse error: syntax error, unexpected ')' in /home/aMlGCD/prog.php on line 57 (which is the closing of array_map.

MC57 Over a year ago

Which version of PHP are you using? It works fine for me. Most likely you're using an older version of PHP and you need to remove the trailing commas.

Abhik Over a year ago

PHP 7.3 (Which is the latest on my server).

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