How to simultaneously sort 2 lists using LINQ?

Question

I have two lists { 7 3 5 } and {9 8 1}.

I want to sort my first list and I want the second list to have the same index permutation as given by the first list.

{3 5 7} => {8 1 9}

Is it possible to do this in a single LINQ statement?

So, to make sure I'm clear, you want to sort the first list, and have the second list sort by that key as well? — James Michael Hare
– James Michael Hare, Commented May 18, 2012 at 15:20

Jon Skeet · Accepted Answer · 2012-05-18 15:21:24Z

43

Sounds like you might want:

var list1 = new List<int> { 7, 3, 5 };
var list2 = new List<int> { 9, 8, 1 };

var orderedZip = list1.Zip(list2, (x, y) => new { x, y } )
                      .OrderBy(pair => pair.x)
                      .ToList();
list1 = orderedZip.Select(pair => pair.x).ToList();
list2 = orderedZip.Select(pair => pair.y).ToList();

answered May 18, 2012 at 15:21

Jon Skeet

1.5m893 gold badges9.3k silver badges9.3k bronze badges

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

9 Comments

Aidan Over a year ago

How is it possible to answer this question in 68 seconds?

James Michael Hare Over a year ago

@Aidan, Because he's Jon Skeet, 'nuff said... :-)

Aidan Over a year ago

He's like the Chuck Norris of SO

James Michael Hare Over a year ago

@Aidan: Hah! Sounds like a good line of jokes... Jon Skeet doesn't need to sort lists, when Jon Skeet arrives they sort themselves.

Matthew Over a year ago

It's an honor to be beaten to a response by Jon Skeet.

|

Matthew · Accepted Answer · 2012-05-18 15:30:06Z

10

You could try using the Zip method:

var sortedPairs = list1
    .Zip(list2, (item1, item2) => new KeyValuePair<int, int>(item1, item2))
    .OrderBy(pair => pair.Key);

Then you could get the first sorted list by:

var sortedList1 = sortedPairs.Select(pair => pair.Key);

And the second list by:

var sortedList2 = sortedPairs.Select(pair => pair.Value);

edited May 18, 2012 at 15:30

answered May 18, 2012 at 15:23

Matthew

29.4k29 gold badges107 silver badges173 bronze badges

Collectives™ on Stack Overflow

How to simultaneously sort 2 lists using LINQ?

2 Answers 2

9 Comments

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

9 Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Related