function launches an external application to view a file or website. The function expects a string expression representing a file (filename
) or a website URL (website_address
). If a file is provided, it is opened in the system's default viewer for that file type. If a website URL is provided, it is opened in the the system's default web browser.
The function returns a logical value of 1 (true) if the file exists and the external application could be launched successfully and 0 (false) otherwise.