C# convert DOMAIN\USER to USER@DOMAIN

Question

I currently have the following code:

string user = @"DOMAIN\USER";
string[] parts = user.Split(new string[] { "\\" }, StringSplitOptions.None);
string user = parts[1] + "@" + parts[0];

Input string user can be in one of two formats:

DOMAIN\USER
DOMAIN\\USER (with a double slash)

Whats the most elegant way in C# to convert either one of these strings to:

USER@DOMAIN

Answer 1

Not sure you would call this most elegant:

string[] parts = user.Split(new string[] {"/"},
                            StringSplitOptions.RemoveEmptyEntries);
string user = string.Format("{0}@{1}", parts[1], parts[0]);

Answer 2

How about this:

        string user = @"DOMAIN//USER";
        Regex pattern = new Regex("[/]+");
        var sp = pattern.Split(user);
        user = sp[1] + "@" + sp[0];
        Console.WriteLine(user);

Answer 3

A variation on Oded's answer might use Array.Reverse:

string[] parts = user.Split(new string[] {"/"},StringSplitOptions.RemoveEmptyEntries);
Array.Reverse(parts);
return String.Join("@",parts);

Alternatively, could use linq (based on here):

return user.Split(new string[] {"/"}, StringSplitOptions.RemoveEmptyEntries)
       .Aggregate((current, next) => next + "@" + current);