如何组合多维数组中的数组并计算值？

Question

I'm a beginner at php and was searching for a solution all day long without success.

I have the following array:

$data = Array
(
[0] => Array
    (
        [my_id] => 1
        [my_post_id] => 123
        [my_status] => 1
        [my_rating] => 5
    )

[1] => Array
    (
        [my_id] => 2
        [my_post_id] => 123
        [my_status] => 1
        [my_rating] => 4
    )

[2] => Array
    (
        [my_id] => 3
        [my_post_id] => 123
        [my_status] => 1
        [my_rating] => 5
    )

[3] => Array
    (
        [my_id] => 4
        [my_post_id] => 456
        [my_status] => 1
        [my_rating] => 5
    )

[4] => Array
    (
        [my_id] => 5
        [my_post_id] => 456
        [my_status] => 1
        [my_rating] => 3
    )
)

and would like to merge the arrays with the same 'my_post_id' and count the values for 'my_status' and 'my_rating' which have the same 'my_post_id'.

At the end, I would like to have the following array:

 $data = Array
(
[0] => Array
    (
        [my_post_id] => 123
        [my_status] => 3
        [my_rating] => 14
    )

[1] => Array
    (
        [my_post_id] => 456
        [my_status] => 2
        [my_rating] => 8
    )
)

I could get arrays with unique 'my_post_id' with the following code but I couldn't find out how to count the other values.

$out = array();
    foreach( $data as $row ) {
        $out[$row['my_post_id']] = $row;
    }
    $array = array_values( $out );

Any help would be much appreciated.

Daniel

Answer 1

This will produce the array you are looking for:

$out = array();
foreach( $data as $row ) {
    if (!isset($out[$row['my_post_id']])) {
        $out[$row['my_post_id']] = Array( "my_id"=>$row['my_id'],
                                          "my_status" => $row["my_status"],
                                          "my_rating" => $row["my_rating"]);
    }
    else {
        $out[$row['my_post_id']]["my_status"] += $row["my_status"];
        $out[$row['my_post_id']]["my_rating"] += $row["my_rating"];
    }

}

results in:

Array
(
    [123] => Array
        (
            [my_id] => 1
            [my_status] => 3
            [my_rating] => 14
        )

    [456] => Array
        (
            [my_id] => 4
            [my_status] => 2
            [my_rating] => 8
        )

)