Get different and common items in two arrays with LINQ

Question

For example, I have two arrays:

var list1 = string[] {"1", "2", "3", "4", "5", "6"};
var list2 = string[] {"2", "3", "4"};

What I'm trying to do is -

Get common items from list1 and list2 (eg. {"2", "3", "4"})
Get different items list1 and list2 (eg. {"1", "5", "6"})

So I've tried with LINQ and -

var listDiff = list1.Except(list2); //This gets the desire result for different items

But,

var listCommon = list1.Intersect(list2); //This doesn't give me desire result. Comes out as {"1", "5", "6", "2", "3", "4"};

Any ideas?

It should work. `list1.Intersect(list2)` returns "2", "3", "4". — nemesv, May 18 '12 at 07:09
You are missing 2 `new` in your syntax. That won't compile. Use: `var list2 = new string[] {"2", "3", "4"};` — juergen d, May 18 '12 at 07:09
Silly me. In fact, Intersect works, just that the other part to output the array to text box was messing up. Thanks all! — Ye Myat Aung, May 18 '12 at 07:11
If `list1` and `list2` already exist, the above systax is fine. This works for me... — MoonKnight, May 18 '12 at 07:12
Ye Myat Aung - You should see a _delete_ link under the question. — H H, May 18 '12 at 07:15
just commenting to let the people who closed it know it helped me a few times, and 25 people who upvoted the answer — Zachary Brooks, Aug 29 '19 at 16:15

score 31 · Accepted Answer · answered May 18 '12 at 07:14

Somehow you have got that result from somewhere else. (Perhaps you are writing out the contents of listDIff first, and thought that it was from listCommon.) The Intersect method does give you the items that exists in both lists:

var list1 = new string[] {"1", "2", "3", "4", "5", "6"};
var list2 = new string[] {"2", "3", "4"};
var listCommon = list1.Intersect(list2);
foreach (string s in listCommon) Console.WriteLine(s);

Output:

2
3
4

Get different and common items in two arrays with LINQ

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