String Arrays in c#. Removing elements from one string array which are their in another string array

Question

I have two string arrays -

            string[] One = new string[3];

            One[0] = "Pen";          
            One[1] = "Pencil";          
            One[2] = "card";

and,

            string[] Two = new string[2];

            Two[0] = "card";          
            Two[1] = "drive";

Now, I want a new string array from these two, such that the final result does not contain any element of the Two array. i.e. it should have, "Pen", "Pencil" only.

Like Union method in c#, is there any similar method which can be used here ?? — Vishwas Joshi, Feb 02 '20 at 10:41
Yes, you can use linq Except method. One.Except(Two).ToArray() — Lior, Feb 02 '20 at 11:05
Does this answer your question? [How to perform set subtraction on arrays in C#?](https://stackoverflow.com/questions/5058609/how-to-perform-set-subtraction-on-arrays-in-c) — SᴇM, Feb 02 '20 at 11:13

Pashupati Khanal · Answer 1 · 2020-02-04T05:07:35.593

5

This simple linq query can give you result.

var res = One.Except(Two);

Further, if in case you need to ignore case, use overload version of above method as:

var res = One.Except(Two, StringComparer.OrdinalIgnoreCase);

OR, Equivalently.

var res  = One.Where(x=>!Two.Contains(x)).ToArray();

edited Feb 04 '20 at 05:07

answered Feb 02 '20 at 10:50

Pashupati Khanal

733
3
11

1

This is one of the easy way using linq. If you want to ignore case, then you can use the overloaded method: "One.Except(Two, StringComparer.OrdinalIgnoreCase)" – Surendra Shrestha Feb 04 '20 at 04:59
Thanks for your ans I will Update It as well. – Pashupati Khanal Feb 04 '20 at 05:02

score 4 · Accepted Answer · answered Feb 02 '20 at 10:43

You can use Linq -

var res = One.Where(x => Two.Find(x) == null);

Or even better:

        string[] One = new string[3];

        One[0] = "Pen";
        One[1] = "Pencil";
        One[2] = "card";
        string[] Two = new string[2];

        Two[0] = "card";
        Two[1] = "drive";

        var res = One.Except(Two);

Athanasios Kataras · Answer 3 · 2020-02-02T10:53:26.530

1

You need something like non-intersect

         string[] One = new string[3];

            One[0] = "Pen";          
            One[1] = "Pencil";          
            One[2] = "card";

        string[] Two = new string[2];

            Two[0] = "card";          
            Two[1] = "drive";

        var nonintersectOne = One.Except(Two);   
        foreach(var str in  nonintersectOne)
           Console.WriteLine(str);

        // Or if you want the non intersect from both
        var nonintersectBoth = One.Except(Two).Union(Two.Except(One)).ToArray();
        foreach(var str in  nonintersect)
           Console.WriteLine(str);

Output 1:

Pen

Pencil

Output 2:

Pen

Pencil

drive

edited Feb 02 '20 at 10:53

answered Feb 02 '20 at 10:46

Athanasios Kataras

25,191
4
32
61

Quite right, updated accordingly. Leaving the secondary solution for anyone who might want it. – Athanasios Kataras Feb 02 '20 at 10:53
Please don't make the answer confusing by adding in superfluous content. – Enigmativity Feb 03 '20 at 23:02

String Arrays in c#. Removing elements from one string array which are their in another string array

3 Answers3