NumericString Sort

[User 10560398]

Hi All, I have a column in my table which contains a string that can have data like below: ABC 1 ABC 10 ABC 2 ABC 100 ADBCDEF - 1 ADBCDEF - 10 ADBCDEF - 3 I need the output to be like: ABC 1 ABC 2 ABC 10 ABC 100 ADBCDEF - 1 ADBCDEF - 3 ADBCDEF - 10 When i apply dataview.sort, it gives output as: ABC 1 ABC 10 ABC 100 ABC 2 I need to sort my datagrid with the above column. Can anyone provide a sorting algorithm to solve this. Thanks Sai

[V 0]

Tricky case. I would split the numerical part and text part, but keep them in one class. * Then you can order by the text first and with the numeric part second through a custom function implementing some sorting algorithm. * or group first by text and with an array of integer attached to them like "ABC" with { 1, 2, 10, 100 } eg. Then you can order the class with the text property and print the concatenated text/integer ordered by the numerical part. * If they can stay split in the dataview you could just do like in a database´s order by clause, simplifying things a bit. Hope this helps.

V.
(MQOTD rules and previous solutions)

OriginalGriff wrote:

V is absolutely right

[Lost User]

It depends. In the general case, that's called Natural Sort, which isn't one specific algorithm but a family of different ways to compare strings such that their order looks "natural". That's an inherently ambiguous requirement, so there are many different implementations. It gets particularly difficult if you want to include dates. If it's just about strings that end in some number of digits, there is an easy ad-hoc solution for that.

[DaveyM69]

This works the way you have described. It may not be very efficient so you may want to optimise it somewhat:

public static int Compare(string first, string second)
    {
        if (object.ReferenceEquals(first, second))
            return 0;
        if (object.ReferenceEquals(null, first)) // second cannot be null
            return -1;
        // neither string can be null
        char\[\] digits = new char\[\] { '0', '1', '2', '3', '4', '5', '6', '7', '8','9' };
        int firstDigitIndex = first.IndexOfAny(digits);
        int secondDigitIndex = second.IndexOfAny(digits);
        string firstLhs = firstDigitIndex == -1 ? first : first.Substring(0, firstDigitIndex);
        string secondLhs = secondDigitIndex == -1 ? second : second.Substring(0, firstDigitIndex);
        int result = firstLhs.CompareTo(secondLhs);
        if (result == 0)
        {
            // left hand sides are equal so sort on numeric part
            int firstInteger = 0;
            int secondInteger = 0;
            if (firstDigitIndex > -1)
                int.TryParse(first.Substring(firstDigitIndex), out firstInteger);
            if (secondDigitIndex > -1)
                int.TryParse(second.Substring(secondDigitIndex), out secondInteger);
            result = firstInteger.CompareTo(secondInteger);
        }
        return result;
    }

Test:

    SortAndWriteList(new List(new string\[\] { "ABC 1", "ABC 10", "ABC 2", "ABC 100" }));
    Console.WriteLine();
    SortAndWriteList(new List(new string\[\] { "ADBCDEF - 1", "ADBCDEF - 10", "ADBCDEF - 3" }));
    Console.WriteLine();
    Console.ReadKey();

    private static void SortAndWriteList(List list)
    {
        if (list != null)
        {
            list.Sort(new Comparison(Compare));
            foreach (string item in list)
                Console.WriteLine(item);
        }
    }

Result:

ABC 1
ABC 2
ABC 10
ABC 100

ADBCDEF - 1
ADBCDEF - 3
ADBCDEF - 10

Dave
Binging is like googling, it just feels dirtier. Please take your VB.NET out of our nice case sensitive forum. Astonish us. Be exceptional. (

[Richard Deeming]

If you want to duplicate the natural sort order used in Windows Explorer, the simplest option is to P/Invoke the StrCmpLogicalW function[^] from shlwapi.dll:

public class LogicalStringComparer : IComparer
{
[DllImport("shlwapi.dll", CharSet=CharSet.Unicode, ExactSpelling=true, SetLastError=true)]
private static extern int StrCmpLogicalW(string x, string y);

public int Compare(string x, string y)
{
    return StrCmpLogicalW(x, y);
}

}

StrCmpLogicalW on MSDN[^]

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