Finding a value in php multidimensional array and adding data to that array

Question

I have a multidimensional JSON array that I need to add values to. The JSON array is external and I cannot change its format.

I've tried doing 3 foreach loops, but then I get myself lost in how to add data to the array. I keep catching myself stuck in a loop.

Here's the JSON:

{
    "positions": [{
        "report_at": "2017-03-13 20:04:10",
        "elev": "0",
        "dir": "0",
        "id": "1"
    }, {
        "report_at": "2017-03-07 00:28:14",
        "elev": "1240",
        "dir": "89",
        "id": "2"
    }]
}

I have unique data I need to add to id 1, and another set of unique data I need to add to id 2.

Here's what I've tried:

$data = json_decode( $result, true );

foreach ( $data as $d ) {
    foreach ( $d as $key => $data ) {
        if ( $data['id'] == '1' ) {
            $data[] = array(
                "online_status" => "1",
                "name" => "Test User",
            );
        } elseif ( $data['id'] == '2' ) {
            $data[] = array(
                "online_status" => "0",
                "name" => "Another User",
            );
        }
    }
}

$json = json_encode( $data );
echo $json;

I think once I can get this figured out, then I can pull data from MySQL, build small arrays based off that data, then add those to these sub-arrays where the ID matches the SQL ID. Any help is appreciated.

Have you tried using $data = array_merge( $data, array(....) ) instead of the $data[] assignment? — Nick
– Nick, Commented Mar 14, 2017 at 21:45

Jakub A. · Accepted Answer · 2017-03-14 21:44:21Z

1

JSON seems to be just object with "positions" field which is array, you need to modify.

$data = json_decode($json, TRUE);

foreach ($data['positions'] as &$userInfo) {
    if ($userInfo['id'] == 1) {
          $userInfo['online_status'] = 'offline';
          $userInfo['name'] = 'Test user';
    }
}

echo json_encode($data);

Notice "&" sign in foreach, which means, that modification made within foreach, will be stored to original array.

Also you should be aware of key=>value naming in foreach. Your second foreach creates variable named $data, which means, that you are loosing pointer to original array!

answered Mar 14, 2017 at 21:44

Jakub A.

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1 Comment

Pat Over a year ago

This works great and adds the items inline with the existing data. Thank you for the explanation of $data, too! Thanks!

RomanPerekhrest · Accepted Answer · 2017-03-15 05:20:58Z

1

Use the following approach:

$data = json_decode($result, true);
    foreach ($data['positions'] as &$item) {
    if ($item['id'] == "1") {
        $item = array_merge($item, ["online_status" => "1", "name" => "Test User"]);
    } else if ($item['id'] == "2") {
        $item = array_merge($item, ["online_status" => "0", "name" => "Another User"]);
    }
}

$json = json_encode($data, JSON_PRETTY_PRINT);
echo $json;

The output:

{
    "positions": [
        {
            "report_at": "2017-03-13 20:04:10",
            "elev": "0",
            "dir": "0",
            "id": "1",
            "online_status": "1",
            "name": "Test User"
        },
        {
            "report_at": "2017-03-07 00:28:14",
            "elev": "1240",
            "dir": "89",
            "id": "2",
            "online_status": "0",
            "name": "Another User"
        }
    ]
}

edited Mar 15, 2017 at 5:20

answered Mar 14, 2017 at 21:53

RomanPerekhrest

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1 Comment

Pat Over a year ago

This works great, but the other answer was a little more in line with what I was going after with data inline and not another nested array. Thank you for taking the time to answer it!

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