在foreach循环中，您可以将值存储在变量中，而不是打印(回显).

In the foreach loop you can store the values ​​in a variable instead of printing (echo).

在foreach之后，您可以打印变量

After the foreach you can then print the variable

function filter_woocommerce_customer_available_downloads($downloads, $customer_id) { 
    // Manipulate download data here, this example we'll get the first 5 downloads in the array
    // $downloads = array_slice($downloads, 0, 5);
    // Sorting the array by Order Ids in DESC order
    arsort($downloads); 

    // Return first five downloads
    return $downloads;
}
add_filter( 'woocommerce_customer_available_downloads', 'filter_woocommerce_customer_available_downloads', 10, 2 );

/**
 * Group Downloadable products by product ID
 *
 * @param array $downloads
 * @return array
 */
function prefix_group_downloadable_products( array $downloads ) {
    $unique_downloads = [];

    foreach ($downloads as $download ) {
        $list = [
            'download_url' => $download['download_url'],
            'file_name'    => $download['file']['name'],
            'orderid'      => $download['order_id']
        ];

        if ( array_key_exists( $download['product_id'], $unique_downloads ) ) {
            $unique_downloads[ $download['product_id'] ]['list'][] = $list;
            continue;
        }

        $data = $download;
        $data['list'] = [ $list ];
        $unique_downloads[ $download['product_id'] ] = $data;
    }

    return $unique_downloads;
}
add_filter( 'woocommerce_customer_get_downloadable_products', 'prefix_group_downloadable_products', 10, 1 );

/**
 * Show number list of downloadable files for group product
 *
 * @param array $download
 * @return void
 */
function prefix_downloads_column_download_file( array $download ) {
    $lists = $download['list'];

    // Sorting the array by Order Ids in DESC order
    arsort($lists); 

    if ( empty( $lists ) ) {
        _e( 'No Download Files', 'storefront' );
        return;
    }

    // Set variable
    $li = '';

    foreach ( $lists as $list ) {
        // Get $order object from order ID 
        $order = wc_get_order( $list['orderid']  );

        $order_date = $order->get_date_completed();

        // Append to
        $li .= '<li><a href="' . esc_url( $list['download_url'] ) . '" class="woocommerce-MyAccount-downloads-file">' . esc_html( $list['file_name'] ) . '</a></li>';
    }

    echo '<ul class="charliesub">';
    echo '<li class="accordion">';
    echo '<h3>' .  $order_date . '</h3>';
    echo '<div>';
    echo '<ol>';

    echo $li;

    echo '</ol>';
    echo '</div>';
    echo '</li>';
    echo '</ul>';
}
add_action( 'woocommerce_account_downloads_column_download-file', 'prefix_downloads_column_download_file' );