Question

I want to combine two relative paths in C#.

For example:

string path1 = "/System/Configuration/Panels/Alpha";
string path2 = "Panels/Alpha/Data";

I want to return

string result = "/System/Configuration/Panels/Alpha/Data";

I can implement this by splitting the second array and compare it in a for loop but I was wondering if there is something similar to Path.Combine available or if this can be accomplished with regular expressions or Linq?

Thanks

Answer 1

Provided that the two strings are always in the same format as in your example, this should work:

string path1 = "/System/Configuration/Panels/Alpha";
string path2 = "Panels/Alpha/Data";

var x = path1.Split('/');
var y = path2.Split('/');

string result = Enumerable.Range(0, x.Count())

                          .Where(i => x.Skip(i)
                                       .SequenceEqual(y.Take(x.Skip(i)
                                                              .Count())))

                          .Select(i => string.Join("/", x.Take(i)
                                                         .Concat(y)))

                          .LastOrDefault();

// result == "/System/Configuration/Panels/Alpha/Data"

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For path1 = "/System/a/b/a/b" and path2 = "a/b/a/b/c" the result is "/System/a/b/a/b/a/b/c". You can change LastOrDefault to FirstOrDefault to get "/System/a/b/a/b/c" instead.

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Note that this algorithm essentially creates all possible combinations of the two paths and isn’t particularly efficient.