PHP Convert array into csv

My solution requires the array be formatted differently than provided in the question:

<?
    $data = array(
        array( 'row_1_col_1', 'row_1_col_2', 'row_1_col_3' ),
        array( 'row_2_col_1', 'row_2_col_2', 'row_2_col_3' ),
        array( 'row_3_col_1', 'row_3_col_2', 'row_3_col_3' ),
    );
?>

We define our function:

<?
    function outputCSV($data) {
        $outputBuffer = fopen("php://output", 'w');
        foreach($data as $val) {
            fputcsv($outputBuffer, $val);
        }
        fclose($outputBuffer);
    }
?>

Then we output our data as a CSV:

<?
    $filename = "example";

    header("Content-type: text/csv");
    header("Content-Disposition: attachment; filename={$filename}.csv");
    header("Pragma: no-cache");
    header("Expires: 0");

    outputCSV($data);
?>

I have used this with several projects, and it works well. I should note that the outputCSV code is more clever than I am, so I am sure I am not the original author. Unfortunately I have lost track of where I got it, so I can't give the credit to whom it is due.