How to compare two List using LINQ in C#

Question

The two lists are like

          LISTONE    "ONE", "TWO", "THREE"
          LISTTWO    "ONE", "TWO", "THREE"

i need to compare the whether the items in two lists are in same order or not.

Is there any way to do this in LINQ

possible duplicate of [Examining two string arrays for equivalence](http://stackoverflow.com/questions/3250887/examining-two-string-arrays-for-equivalence) — Yuriy Faktorovich, Jul 23 '10 at 15:46
The SequenceEqual operator (extension method) seems like what you'd want, unless ListOne is allowed to have items that are not in ListTwo or vice-versa. — Dr. Wily's Apprentice, Jul 23 '10 at 15:49
possible duplicate of [Is there a built-in method to compare collections in C#?](http://stackoverflow.com/questions/43500/is-there-a-built-in-method-to-compare-collections-in-c) — nawfal, Nov 08 '13 at 20:27

score 8 · Accepted Answer · edited May 23 '17 at 12:13

8

Maybe:

bool equal = collection1.SequenceEqual(collection2);

See also: Comparing two collections for equality irrespective of the order of items in them

edited May 23 '17 at 12:13

Community

1
1

answered Jul 23 '10 at 15:45

Matthew Groves

25,181
9
71
121

The `OrderBy` calls would mean that the order was ignored: but Pramodh wants to see if they are in the same order – Kieren Johnstone Jul 23 '10 at 15:46
yeah sorry, don't know why I initially put those in there :) – Matthew Groves Jul 23 '10 at 22:08
+1 great tip - thanks - you saved me from writing some terrible, terrible code! – adrianos Jun 17 '11 at 10:01

score 2 · Answer 2 · edited Dec 12 '11 at 19:19

2

Determine if both lists contain the same data in same order:

bool result = list1.SequenceEqual(list2);

Same entries in different order:

bool result = list1.Intersect(list2).Count() == list1.Count;

edited Dec 12 '11 at 19:19

answered Jul 23 '10 at 15:47

Florian Reischl

3,788
1
24
19

Watch out with the second version. The `Intersect` method uses set intersection, so you might get unexpected results if one or both of the lists contain duplicates. – LukeH Jul 23 '10 at 15:52

score 1 · Answer 3 · answered Jul 23 '10 at 16:11

1

If you know there can't be duplicates:

bool result = a.All(item => a.IndexOf(item) == b.IndexOf(item));

Otherwise

bool result = a.SequenceEquals(b)

answered Jul 23 '10 at 16:11

duraz0rz

387
1
2
10

score 0 · Answer 4 · answered Jul 23 '10 at 15:46

0

List<string> list1;
List<string> list2;

bool sameOrder = list1.SequenceEqual(list2);

answered Jul 23 '10 at 15:46

Martin Ingvar Kofoed Jensen

4,241
2
29
31

score 0 · Answer 5 · answered Jul 23 '10 at 15:49

0

These are the correct answers, but as a thought, If you know the lists will have the same data but may be in different order, Why not just sort the lists to guarantee the same order.

var newList = LISTONE.OrderBy(x=>x.[sequence]).ToList();

answered Jul 23 '10 at 15:49

EKet

7,272
15
52
72

How to compare two List using LINQ in C#

5 Answers5

Linked