When is File.join useful?

Question

From reading the documentation, it\'s apparent that File.join joins the given parameters with the / character.
When is using this, as opposed to filenames.join(\'/\')<

Answer 1

It will use File::SEPARATOR, which in theory need not be /.

Answer 2

There is another, subtle difference:

File.join('foo','bar')
#=> "foo/bar"
['foo','bar'].join('/')
#=> "foo/bar"

But, if you pass an argument already ending with / (which is quite often when working with paths), you won't have two slashes in the result:

File.join('foo/','bar')
#=> "foo/bar"
['foo/','bar'].join('/')
#=> "foo//bar"