PHP insert array values to csv column

I have a large (size ~ 12k) 2D array of data like below and I want to insert these data into a csv file.

$data = array
(
    'a' => array
    (
        0 => 111,
        1 => 222,
        2 => 333,
        3 => 444,
    ),
    'b' => array
    (
        0 => 555,
        1 => 666,
        2 => 777,
        3 => 888,
    ),
    'c' => array
    (
        0 => 999,
        1 => 000,
        2 => 111,
        3 => 222,
    ),
);

Here 'a', 'b', and 'c' would be the CSV header row, and corresponding array values should be inserted like below:-

I know fputcsv can be used to insert the data but it insert the array values as a row in the csv but in my case I want to insert the array values to a csv column.

Is there any simpler way to insert all the array values to the csv columns like above table?

Assuming that each sub-array contains the same count of values, you can achieve your goal with just a few lines of code:

• use array_keys to get all the column names from your array
• iterate each sub-array to compose the single row, assuming that each value of that row is in the same array index position

$data = array
(
    'a' => array
    (
        0 => 111,
        1 => 222,
        2 => 333,
        3 => 444,
    ),
    'b' => array
    (
        0 => 555,
        1 => 666,
        2 => 777,
        3 => 888,
    ),
    'c' => array
    (
        0 => 999,
        1 => 000,
        2 => 111,
        3 => 222,
    ),
);
    
$fp = fopen('file.csv', 'w');

// headers
fputcsv($fp, array_keys($data));

// rows contents
for($i = 0; $i<count(current($data)); $i++) {
    $row = [];
    foreach($data as $k => $v) {
        $row[] = $v[$i];
    }
    fputcsv($fp, $row);
}
    
fclose($fp);

Try it online on https://onlinephp.io/c/735bc, with this results:

a,b,c
111,555,999
222,666,0
333,777,111
444,888,222

In the official documentation you can find many other useful array functions.