Best way to break a string on the last dot on C#

Question

What would be the best way and more idiomatic to break a string into two at the place of the last dot? Basically separating the extension from the rest of a path in a file path or URL. So far what I'm doing is Split(".") and then String.Join(".") of everything but the last part. Sounds like using a bazooka to kill flies.

Answer 1

To get the path without the extension, use

System.IO.Path.GetFileNameWithoutExtension(fileName)

and to get the extenstion (including the dot), use

Path.GetExtension(fileName)

EDIT:

Unfortunately GetFileNameWithoutExtension strips off the leading path, so instead you could use:

if (path == null)
{
    return null;
}
int length = path.LastIndexOf('.');
if (length == -1)
{
    return path;
}
return path.Substring(0, length);

Answer 2

You could use Path.GetFilenameWithoutExtension()

or if that won't work for you:

int idx = filename.LastIndexOf('.');

if (idx >= 0)
   filename = filename.Substring(0,idx);