CODEWITHSUNDEEP
c#asp.netc#-4.0collections
Colin Pear
Colin Pear

Reputation: 3100

Trouble ordering a collection of objects by a numeric string value property

So I have a class that contains a property called myNumber. It looks like this: 

public class MyThing
{
    public int name{ get; set; }
    public string myNumber{ get; set; }
}

The value contained in myNumber can look like this 12-24 or 12-024.

I would like to order a collection of these objects (IEnumerable<MyThing> myCollection) by myNumber descending but I am not sure how to go about doing this.

I tried myCollection.OrderByDescending(f => f.myNumber) but its not quite what I was expecting. I would expect 12-22, 13-01, 12-030 to order like this:

13-01 
12-030
12-22

Upvotes: 1

Views: 68

Answers (2)

Tim Schmelter
Tim Schmelter

Reputation: 460208

You can order it like a Version. Therefore you can split by '-' and use the first part as major- and the last part as minor version:

var orderedLikeVersion = myCollection
    .Select(t => new
    {
        Thing = t,
        Parts = t.myNumber.Split('-')
    }).Select(x => new
    {
        x.Thing,
        Version = new Version(int.Parse(x.Parts[0]), int.Parse(x.Parts[1]))
    })
    .OrderByDescending(x => x.Version)
    .Select(x => x.Thing);

Demo with your desired result.

Upvotes: 2

AaronLS
AaronLS

Reputation: 38364

I'm guessing you got this order?

13-01 
12-22
12-030

This would be correct by alphabetic conventions. 12-2* is greater than 12-0* since 2 comes after 0.

It also seems correct by numeric conventions, since 22 is also greater than 03, and 2 is greater than 0.

So I'm not sure in your expected ordering, why you interpret 12-030 as being greater than 12-22? Is the part after the hyphen supposed to allow leading zeros to be truncated? If you did that, then 12-30 would equal 12-030 and I would ask myself, what is the purpose of the leading 0.

Upvotes: 0

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