Why is it recommended to avoid using multidimensional arrays with fputcsv in PHP?

When using fputcsv in PHP, it is recommended to avoid using multidimensional arrays because fputcsv expects a one-dimensional array as input. If a multidimensional array is passed to fputcsv, it will not handle the data correctly and may produce unexpected results. To solve this issue, you can flatten the multidimensional array into a one-dimensional array before passing it to fputcsv.

// Sample multidimensional array
$data = [
    [1, 'John', 'Doe'],
    [2, 'Jane', 'Smith']
];

// Flatten the multidimensional array
$flattenedData = [];
foreach ($data as $row) {
    $flattenedData[] = $row;
}

// Open a file handle
$fp = fopen('output.csv', 'w');

// Write the flattened data to the CSV file
foreach ($flattenedData as $row) {
    fputcsv($fp, $row);
}

// Close the file handle
fclose($fp);