Merge, remove duplicates and sort associative array in php

Question

I am trying to merge arrays in php. Everything is coming from a database and two different results could look like this:

array[0]['id_user'] = 1
array[0]['tokenId'] = 123
array[1]['id_user'] = 2
array[1]['tokenId'] = 456
array[2]['id_user'] = 5
array[2]['tokenId'] = 789

array[0]['id_user'] = 1
array[0]['tokenId'] = 123
array[1]['id_user'] = 2
array[1]['tokenId'] = 752
array[2]['id_user'] = 3
array[2]['tokenId'] = 789

Using array_merge() and then array_unique() should give me something like this I expect:

unique_and_merged_array[0]['id_user'] = 1
unique_and_merged_array[0]['tokenId'] = 123
unique_and_merged_array[1]['id_user'] = 2
unique_and_merged_array[1]['tokenId'] = 456
unique_and_merged_array[2]['id_user'] = 5
unique_and_merged_array[2]['tokenId'] = 789
unique_and_merged_array[3]['id_user'] = 2
unique_and_merged_array[3]['tokenId'] = 752
unique_and_merged_array[4]['id_user'] = 3
unique_and_merged_array[4]['tokenId'] = 789

Then how can I sort by id_user value? I'm not sure to understand the different sorting php functions ...

You can have the id_user value be the key of an associative array and have the value be an array of tokenId's — user5051310
– user5051310, Commented Oct 8, 2015 at 5:31

Narendrasingh Sisodia · Accepted Answer · 2015-10-08 05:45:41Z

2

You can simply use usort like as

usort($unique_and_merged_array,function($a,$b){
   return $a['id_user'] - $b['id_user'];
});
print_r($result);

Output:

Array
(
    [0] => Array
        (
            [id_user] => 1
            [tokenId] => 123
        )

    [1] => Array
        (
            [id_user] => 2
            [tokenId] => 752
        )

    [2] => Array
        (
            [id_user] => 2
            [tokenId] => 456
        )

    [3] => Array
        (
            [id_user] => 3
            [tokenId] => 789
        )

    [4] => Array
        (
            [id_user] => 5
            [tokenId] => 789
        )

)

Demo

edited Oct 8, 2015 at 5:45

answered Oct 8, 2015 at 5:38

Narendrasingh Sisodia

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2 Comments

Nerdwood Over a year ago

That's better. ;) Same as the other answer though except for an anonymous function. :)

Narendrasingh Sisodia Over a year ago

As you can simply make it one liner then why to use anonymous function @Nerdwood

Nerdwood · Accepted Answer · 2015-10-08 05:35:40Z

The PHP-based solution could look something like this:

//Define arrays for testing
$array1[0]['id_user'] = 1;
$array1[0]['tokenId'] = 123;
$array1[1]['id_user'] = 2;
$array1[1]['tokenId'] = 456;
$array1[2]['id_user'] = 5;
$array1[2]['tokenId'] = 789;

$array2[0]['id_user'] = 1;
$array2[0]['tokenId'] = 123;
$array2[1]['id_user'] = 2;
$array2[1]['tokenId'] = 752;
$array2[2]['id_user'] = 3;
$array2[2]['tokenId'] = 789;

//Define sort function - compares arrays using the 'id_user' value
function sortByUserId($array1, $array2)
{
    if ($array1['id_user'] == $array2['id_user']) {
        return 0;
    }
    return ($array1['id_user'] < $array2['id_user']) ? -1 : 1;
}

//Merge arrays
$unique_and_merged_array = array_merge($array1, $array2);

//Remove duplicate entries - note SORT_REGULAR in order to work with multidimensional arrays
$unique_and_merged_array = array_unique($unique_and_merged_array, SORT_REGULAR);

//Sort the arrays
uasort($unique_and_merged_array, 'sortByUserId');

//Enjoy  ;)
var_dump($unique_and_merged_array);

Amit · Accepted Answer · 2015-10-08 05:48:27Z

1

function cmp($a,$b){
         if ($a["id_user"] == $b["id_user"]) {
            return 0;
        }
        return ($a < $b) ? -1 : 1;
    }

    $unique_and_merged_array = array();
    $unique_and_merged_array[0]['id_user'] = 1;
    $unique_and_merged_array[0]['tokenId'] = 123;
    $unique_and_merged_array[1]['id_user'] = 2;
    $unique_and_merged_array[1]['tokenId'] = 456;
    $unique_and_merged_array[2]['id_user'] = 5;
    $unique_and_merged_array[2]['tokenId'] = 789;
    $unique_and_merged_array[3]['id_user'] = 2;
    $unique_and_merged_array[3]['tokenId'] = 752;
    $unique_and_merged_array[4]['id_user'] = 3;
    $unique_and_merged_array[4]['tokenId'] = 789;
    usort($unique_and_merged_array, "cmp");

answered Oct 8, 2015 at 5:48

Amit

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1 Comment

Amit Over a year ago

you can use usort function as above

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