IComparer for natural sorting

Question

I have been hunting around for a solution to this for a while now.

When I sort the below using a string sort I have a list of:

I really want the list to be:

A numerical sort does not do the job either.

take a look at http://www.codeproject.com/KB/string/NaturalSortComparer.aspx — Glory Raj, Dec 19 '11 at 23:08
@pratapchandra - should just make your comment an official answer. — Jagd, Dec 19 '11 at 23:16

Ry- · Answer 1 · 2011-12-19T23:42:20.453

4

If you have LINQ, you can use OrderBy:

Regex digitPart = new Regex(@"^\d+", RegexOptions.Compiled);
...
myList.OrderBy(x => int.Parse(digitPart.Match(x).Value))

edited Dec 19 '11 at 23:42

answered Dec 19 '11 at 23:16

Ry-

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Worked for me, but I had to change Integer.Parse to Int32.Parse, and .value should be capitalized. Syntax, meh... – Jagd Dec 19 '11 at 23:37
@Jagd: Oops :P I'm a VB.NET person and it's `Integer` there. – Ry- Dec 19 '11 at 23:42
It's not clear from the question whether the OP wants a full natural search that would also order "A1", "A2", "Bumblebee" in that order. – Jon Hanna Dec 20 '11 at 00:03
@minitech - Oh, duh. I should have realized that! *smacks head* :) – Jagd Dec 20 '11 at 16:19

score 3 · Answer 2 · edited May 23 '17 at 12:25

3

The easiest is to wrap the Win32 API call as explained in https://stackoverflow.com/a/248613/631687

edited May 23 '17 at 12:25

Community

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answered Dec 19 '11 at 23:07

John Arlen

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score 3 · Answer 3 · answered Dec 21 '11 at 01:29

using System;
using System.Collections.Generic;
using System.Text.RegularExpressions;

public class NumStrCmp : IComparer<string> {
    public int Compare(string x, string y){
        Regex regex = new Regex(@"(?<NumPart>\d+)(?<StrPart>\D*)",RegexOptions.Compiled);
        var mx = regex.Match(x);
        var my = regex.Match(y);
        var ret = int.Parse(mx.Groups["NumPart"].Value).CompareTo(int.Parse(my.Groups["NumPart"].Value));
        if(ret != 0) return ret;
        return mx.Groups["StrPart"].Value.CompareTo(my.Groups["StrPart"].Value);
    }
}

class Sample {
    static public void Main(){
        var data = new List<string>() {"10","10b","1111","1164","1174","23","23A","23B","23D","23E"};
        data.Sort(new NumStrCmp());
        foreach(var x in data){
            Console.WriteLine(x);
        }
   }
}

IComparer for natural sorting

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