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phparraysloopsmultidimensional-arrayextract
Ashvic Godinho
Ashvic Godinho

Reputation: 70

Getting the first key in a multidimensional array with PHP

I have a multidimensional array called $test:

Array (
    [First item] => Array (
        [screen] => 2
        [1] => 2
        [2] => 2
        [3] => 2
        [4] => 2
    )
    [Second Item] => Array (
        [screen] => 3
        [1] => 3
        [2] => 3
        [3] => 3
        [4] => 3
    )
)

I am trying to get the keys: screen, 1, 2, 3, and 4.
They are the same for First item and Second item. Do you know how I can loop through this array to get those values? So, basically getting the keys for the first array in my multidimensional array. Thank you!

Upvotes: 1

Views: 3390

Answers (3)

Lorenz Lo Sauer
Lorenz Lo Sauer

Reputation: 24740

It depends on what you are trying to archive:

$test = Array (
    "First item" => Array (
    "screen" => 2,
        1 => 2,
        2 => 2,
        3 => 2,
        4 => 2,
    ),
    "Second Item" => Array (
    "screen" => 3,
        1 => 3,
        2 => 3,
        3 => 3,
        4 => 3,
    )
);

To get all the keys

$vals = [];
foreach($test as $k=>$v){
    $vals = array_merge($vals, array_keys($v));
}

this will yield you: 

Array
(
    [0] => screen
    [1] => 1
    [2] => 2
    [3] => 3
    [4] => 4
    [5] => screen
    [6] => 1
    [7] => 2
    [8] => 3
    [9] => 4
)

Separated in another multidimensional array:

foreach($arr as $k=>$v){
    $vals[] = array_keys($v);
}

Only the unique keys:

foreach($test as $k=>$v){
    $vals = array_unique(array_merge($vals, array_keys($v)));
}

Upvotes: 0

jeroen
jeroen

Reputation: 91744

That would be something like:

$keys = array_keys(reset($your_array));

reset() gets the first value of your array and array_keys() the keys of the resulting array.

You might want to split it in two lines using a temporary variable to avoid strict warnings.

Upvotes: 1

George Brighton
George Brighton

Reputation: 5151

How about this:

$keys = array_keys($test['First item']);

Or if you want to do it manually:

$keys = array();
foreach($test['First item'] as $key => $value) {
    $keys[] = $key;
}

Upvotes: 1

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