C# Collection of Lists - Sorting

Question

I'm looking for an efficient way to "link" arrays/lists to each other and sort all of the lists/arrays synchronously based on one of the arrays.

For example lets say I have three lists:

List<double> Data1;
List<double> Data2;
List<double> Data3;

The items inside the lists are obviously not structurally related, but I want them to be. For instance Data1[0], Data2[0] and Data3[0] are related.

So now I want to sort the collection of the three lists based on Data1 from largest to smallest. How can I do this so that all three lists stay synchronised?

Thank you in advance for your help!

please show some source code... what have you tried ? what is not working ? — Yahia
– Yahia, Commented May 20, 2012 at 12:22
I have not tried anything since I don't know where to begin! I read through a lot of articles but I cannot seem to get the sort of functionality that I need. I think my requirements are pretty basic so not sure why I cannot find relevant information — ceds
– ceds, Commented May 20, 2012 at 12:24

Guffa · Accepted Answer · 2012-05-20 12:36:01Z

5

Make the items structurally related:

public class Data {
  public double Data1 { get; set; }
  public double Data2 { get; set; }
  public double Data3 { get; set; }
}

Having a List<Data>, you can easily sort the items on one of the properties:

theList.Sort((x, y) => x.Data2.CompareTo(y.Data2));

answered May 20, 2012 at 12:36

Guffa

703k111 gold badges760 silver badges1k bronze badges

Sign up to request clarification or add additional context in comments.

3 Comments

ceds Over a year ago

Hey, this will fit the best into my application. Thanks a lot!

Douglas Over a year ago

@user1035217: This is also the best design for code maintainability.

KennyZ Over a year ago

Absolutely. If they should be structurally related, then relate them. Also, the class Data could implement IComparable as an alternative way of sorting...though I like the Lambda method here.

Douglas · Accepted Answer · 2012-05-20 14:22:36Z

1

I would create a list of an anonymous type that combines the values from all three respective lists together, sort based on the field you want, and then project the sorted values back into their respective lists:

var combined =
    Enumerable.Range(0, Data1.Count)
              .Select(i => new
              {
                  Item1 = Data1[i],
                  Item2 = Data2[i],
                  Item3 = Data3[i],
              })
              .OrderBy(c => c.Item1)
              .ToList();

Data1 = combined.Select(c => c.Item1).ToList();
Data2 = combined.Select(c => c.Item2).ToList();
Data3 = combined.Select(c => c.Item3).ToList();

edited May 20, 2012 at 14:22

answered May 20, 2012 at 12:38

Douglas

55.1k14 gold badges145 silver badges193 bronze badges

Comments

Dave Bish · Accepted Answer · 2012-05-20 12:24:28Z

1

You can use Zip to tie the arrays together, and then use the projected type to order by a particular point:

List<double> Data1;
List<double> Data2;
List<double> Data3;

var orderedByDataOne = Data1
    .Zip(Data2, (one, two) => new {one, two})
    .Zip(Data3, (zipped, three) => new {zipped.one, zipped.two, three})
    .OrderBy(x => x.one)

answered May 20, 2012 at 12:24

Dave Bish

19.7k7 gold badges50 silver badges63 bronze badges

Collectives™ on Stack Overflow

C# Collection of Lists - Sorting

3 Answers 3

3 Comments

Comments

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

3 Answers 3

3 Comments

Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Related