Question

I would like to calculate duplicate values in my array by “groupid”:

Example:

Array
(
    [0] => Array
        (
            [id] => 1230
            [groupid] => 177
            [activity_group_last] => 1229
            [name] => First name
        )

    [1] => Array
        (
            [id] => 1231
            [groupid] => 177
            [activity_group_last] => 1229
            [name] => Second name
        )

    [2] => Array
        (
            [id] => 1232
            [groupid] => 178
            [activity_group_last] => 1229
            [name] => Other name
        )

)

Output array (2 groupid = 177 and 1 groupid = 178):

Array
(
    [0] => Array
        (
            [id] => 1231
            [groupid] => 177
            [activity_group_last] => 1229
            [name] => Second name
            [count] => 2

        )

    [1] => Array
        (
            [id] => 1232
            [groupid] => 178
            [activity_group_last] => 1229
            [name] => Other name
            [count] => 1
        )
)

Thanks!

Answer 1

If $value contains your array, then:

$count = array_count_values(array_map(function($item) {
    return $item['groupid'];
}, $value));
var_dump($count);

$_tmp = $count;
$unique = array_filter($value, function(&$item) use (&$_tmp, $count) {
    if (!--$_tmp[$item['groupid']]) {
        $item['count'] = $count[$item['groupid']];
        return true;
    }
    return false;
});
var_dump($unique);

results in:

array(2) {
  [1]=>
  array(5) {
    ["id"]=>
    int(1231)
    ["groupid"]=>
    int(177)
    ["activity_group_last"]=>
    int(1229)
    ["name"]=>
    string(11) "Second name"
    ["count"]=>
    int(2)
  }
  [2]=>
  array(5) {
    ["id"]=>
    int(1232)
    ["groupid"]=>
    int(178)
    ["activity_group_last"]=>
    int(1229)
    ["name"]=>
    string(10) "Other name"
    ["count"]=>
    int(1)
  }
}