How do I remove duplicates from a C# array?

Question

I have been working with a string[] array in C# that gets returned from a function call. I could possibly cast to a Generic collection, but I was w

Answer 1

  private static string[] distinct(string[] inputArray)
        {
            bool alreadyExists;
            string[] outputArray = new string[] {};

            for (int i = 0; i < inputArray.Length; i++)
            {
                alreadyExists = false;
                for (int j = 0; j < outputArray.Length; j++)
                {
                    if (inputArray[i] == outputArray[j])
                        alreadyExists = true;
                }
                        if (alreadyExists==false)
                        {
                            Array.Resize<string>(ref outputArray, outputArray.Length + 1);
                            outputArray[outputArray.Length-1] = inputArray[i];
                        }
            }
            return outputArray;
        }

Answer 2

The following tested and working code will remove duplicates from an array. You must include the System.Collections namespace.

string[] sArray = {"a", "b", "b", "c", "c", "d", "e", "f", "f"};
var sList = new ArrayList();

for (int i = 0; i < sArray.Length; i++) {
    if (sList.Contains(sArray[i]) == false) {
        sList.Add(sArray[i]);
    }
}

var sNew = sList.ToArray();

for (int i = 0; i < sNew.Length; i++) {
    Console.Write(sNew[i]);
}

You could wrap this up into a function if you wanted to.

Answer 3

Simple solution:

using System.Linq;
...

public static int[] Distinct(int[] handles)
{
    return handles.ToList().Distinct().ToArray();
}

Answer 4

strINvalues = "1,1,2,2,3,3,4,4";
strINvalues = string.Join(",", strINvalues .Split(',').Distinct().ToArray());
Debug.Writeline(strINvalues);

Kkk Not sure if this is witchcraft or just beautiful code

1 strINvalues .Split(',').Distinct().ToArray()

2 string.Join(",", XXX);

1 Splitting the array and using Distinct [LINQ] to remove duplicates 2 Joining it back without the duplicates.

Sorry I never read the text on StackOverFlow just the code. it make more sense than the text ;)

Answer 5

Removing duplicate and ignore case sensitive using Distinct & StringComparer.InvariantCultureIgnoreCase

string[] array = new string[] { "A", "a", "b", "B", "a", "C", "c", "C", "A", "1" };
var r = array.Distinct(StringComparer.InvariantCultureIgnoreCase).ToList();
Console.WriteLine(r.Count); // return 4 items

Answer 6

you can using This code when work with an ArrayList

ArrayList arrayList;
//Add some Members :)
arrayList.Add("ali");
arrayList.Add("hadi");
arrayList.Add("ali");

//Remove duplicates from array
  for (int i = 0; i < arrayList.Count; i++)
    {
       for (int j = i + 1; j < arrayList.Count ; j++)
           if (arrayList[i].ToString() == arrayList[j].ToString())
                 arrayList.Remove(arrayList[j]);