Sorting a List of Strings numerically (1,2,…,9,10 instead of 1,10,2)

Question

I have a List like this:

var l = new List {\"bla 1.txt\",\"bla 2.txt\",\"bla 10.txt\",\"bla 3.txt\"};

If i call l.Sort(), the

Answer 1

The best approach is making use of IComparer. This has already been done and can be found on code project.

Answer 2

Why not write something that will extract a number from a string, like this?

// Note: This could very well be a bad implementation. I'm not too great with Regex.
static int ExtractNumber(string text)
{
    Match match = Regex.Match(text, @"(\d+)");
    if (match == null)
    {
        return 0;
    }

    int value;
    if (!int.TryParse(match.Value, out value))
    {
        return 0;
    }

    return value;
}

Then you could sort your list using:

list.Sort((x, y) => ExtractNumber(x).CompareTo(ExtractNumber(y)));

This strikes me as pretty inefficient, but it should be functional at least.

Answer 3

You could implement your own IComparer that maybe uses a regular expression on the input ("bla 1.txt"), converts that to an int, and peforms the comparison on that parsed value.