How to check duplicates in string array in C# windows form

Question

I have the following string with comma between in my windows form C#

string computernames = "Computer1,Computer2,Computer3,Computer2,Computer1";

as you see there are duplicates of Computer1 and Computer2.
How can I check those duplicates?

I tried the following but it doesn't find any duplicate.
How should I write my code?

string[] arraylist =  computernames.Split(',');
var groups = arraylist.GroupBy(v => v);
foreach (var item in groups)
{
    if(item.Count() > 1)
    {
       MessageBox.Show("There is dubblication of computer name");
       return;
   }
}

Here's something that may be helpful https://stackoverflow.com/questions/19757992/how-do-i-check-if-my-array-has-repeated-values-inside-it . Here's another way to do this as well, `var dupsExist = !arraylist.All(new HashSet().Add);` — Trevor, Mar 12 '21 at 21:06
Please review [MCVE] guidance on posting code to make your future questions better. The code posted here *does not* demonstrate the problem at all (which you should have found yourself by simply running it). — Alexei Levenkov, Mar 12 '21 at 21:20

score 2 · Accepted Answer · answered Mar 12 '21 at 21:02

2

Your code works as expected. Not sure why you don't get the message, however you could simplify it and reduce to a single line with

if(arraylist.GroupBy(v => v).Any(v => v.Count() > 1))
    MessageBox.Show("There are duplicate computer's name");

answered Mar 12 '21 at 21:02

Steve

213,761
22
232
286

score 0 · Answer 2 · answered Mar 12 '21 at 21:02

0

public static bool CheckfrDuplicates(string[] array)
      {
          var duplicates = array
           .GroupBy(p => p)
           .Where(g => g.Count() > 1)
           .Select(g => g.Key);


          return (duplicates.Count() > 0);



      }

answered Mar 12 '21 at 21:02

Nonik

645
4
11

@Steve thank you so much. Maybe I shouldn't loop inside but now it's working as expect. And thank you everybody for your response. I love you guys ! – Anna Mar 12 '21 at 21:12
Please don't post only code as answer, but also provide an explanation what your code does and how it solves the problem of the question. Answers with an explanation are usually more helpful and of better quality, and are more likely to attract upvotes. – Mark Rotteveel Mar 14 '21 at 08:25

How to check duplicates in string array in C# windows form

2 Answers2