Format::to_csv PHP Method

    public function to_csv($data = NULL, $delimiter = ',', $enclosure = '"')
    {
        // Use a threshold of 1 MB (1024 * 1024)
        $handle = fopen('php://temp/maxmemory:1048576', 'w');
        if ($handle === FALSE) {
            return NULL;
        }
        // If no data is passed as a parameter, then use the data passed
        // via the constructor
        if ($data === NULL && func_num_args() === 0) {
            $data = $this->_data;
        }
        // If NULL, then set as the default delimiter
        if ($delimiter === NULL) {
            $delimiter = ',';
        }
        // If NULL, then set as the default enclosure
        if ($enclosure === NULL) {
            $enclosure = '"';
        }
        // Cast as an array if not already
        if (is_array($data) === FALSE) {
            $data = (array) $data;
        }
        // Check if it's a multi-dimensional array
        if (isset($data[0]) && count($data) !== count($data, COUNT_RECURSIVE)) {
            // Multi-dimensional array
            $headings = array_keys($data[0]);
        } else {
            // Single array
            $headings = array_keys($data);
            $data = [$data];
        }
        // Apply the headings
        fputcsv($handle, $headings, $delimiter, $enclosure);
        foreach ($data as $record) {
            // If the record is not an array, then break. This is because the 2nd param of
            // fputcsv() should be an array
            if (is_array($record) === FALSE) {
                break;
            }
            // Suppressing the "array to string conversion" notice.
            // Keep the "evil" @ here.
            $record = @array_map('strval', $record);
            // Returns the length of the string written or FALSE
            fputcsv($handle, $record, $delimiter, $enclosure);
        }
        // Reset the file pointer
        rewind($handle);
        // Retrieve the csv contents
        $csv = stream_get_contents($handle);
        // Close the handle
        fclose($handle);
        return $csv;
    }