C# Regex sorting letter and number strings

Question

I have a list that needs ordering say:

R1-1
R1-11
R2-2
R1-2

this needs to be ordered:

R1-1
R1-2
R1-11
R2-2

Currently I am using the C# Regex.Replace method and adding a 0 before the occurance of single numbers at the end of a string with something like:

Regex.Replace(inString,@"([1-9]$)", @"0$2")

I'm sure there is a nicer way to do this which I just can't figure out. Does anyone have a nice way of sorting letter and number strings with regex?

---

I have used Greg's method below to complete this and just thought I should add the code I am using for completeness:

public static List<Rack> GetRacks(Guid aisleGUID)
    {
        log.Debug("Getting Racks with aisleId " + aisleGUID);
        List<Rack> result = dataContext.Racks.Where(
                               r => r.aisleGUID == aisleGUID).ToList();
        return result.OrderBy(r => r.rackName, new NaturalStringComparer()).ToList();
    }

Answer 1

I think what you're after is natural sort order, like Windows Explorer does? If so then I wrote a blog entry a while back showing how you can achieve this in a few lines of C#.

Note: I just checked and using the NaturalStringComparer in the linked entry does return the order you are looking for with the example strings.

Answer 2

You can write your own comparator and use regular expressions to compare the number between "R" and "-" first, followed by the number after "-", if the first numbers are equal.

Sketch:

public int Compare(string x, string y)
{
    int releaseX = ...;
    int releaseY = ...;
    int revisionX = ...;
    int revisionY = ...;

    if (releaseX == releaseY)
    {
        return revisionX - revisionY;
    }
    else
    {
        return releaseX - releaseY;
    }
}