Question

How to delete duplicate elements from one dimensional array of integers in C#

Answer 1

using System;
using System.Collections.Generic;

namespace ConsoleApplication1
{
    class Program
    {
        static void Main(string[] args)
        {
            int[] arr = { 1, 2, 3, 2, 5, 6, 6, 2 };

            arr = RemoveDuplicates(arr);

            foreach (var item in arr)
                Console.Write(item.ToString() + " ");
        }
        public static int[] RemoveDuplicates(int[] arr)
        {
            HashSet<int> set = new HashSet<int>(arr);
            int[] result = new int[set.Count];
            set.CopyTo(result);

            return result;
        }
    }
}

/*
run:
   
1 2 3 5 6
  
*/

 

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Answer 2

using System;

namespace ConsoleApplication1
{
    class Program
    {
        static void Main(string[] args)
        {
            int[] arr = { 1, 2, 3, 2, 5, 6, 6, 2 };
            int size = arr.Length, k;

            for (int i = 0; i < size; i++)
            {
                for (int j = i + 1; j < size;)
                {
                    if (arr[j] == arr[i])
                    {
                        for (k = j; k < size - 1; k++)
                        {
                            arr[k] = arr[k + 1];
                        }
                        size--;
                        arr[k] = 0;
                    }
                    else
                        j++;
                }
            }
            Console.WriteLine("Array without duplicate elements:");
            for (int i = 0; i < size; i++)
                Console.Write("{0,3}", arr[i]);

            Console.WriteLine("\nArray with zero set elements instead the duplicates:");
            foreach (var item in arr)
                Console.Write(item.ToString() + " ");
        }
    }
}

/*
run:
   
Array without duplicate elements:
  1  2  3  5  6
Array with zero set elements instead the duplicate elements:
1 2 3 5 6 0 0 0
  
*/

 

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Answer 3

using System;
using System.Collections.Generic;

namespace ConsoleApplication1
{
    class Program
    {
        static void Main(string[] args)
        {
            int[] arr = { 1, 2, 3, 2, 5, 6, 6, 2, 1 };

            arr = RemoveDuplicates(arr);

            foreach (var item in arr)
                Console.Write(item.ToString() + " ");
        }
        public static int[] RemoveDuplicates(int[] arr)
        {
            List<int> list = new List<int>();

            foreach (int n in arr)
                if (!list.Contains(n))
                    list.Add(n);

            return list.ToArray();
        }
    }
}

/*
run:
   
1 2 3 5 6
  
*/

 

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Answer 4

using System;
using System.Linq;

namespace ConsoleApplication1
{
    class Program
    {
        static void Main(string[] args)
        {
            int[] arr = { 1, 2, 3, 2, 5, 6, 6, 2, 1, 1, 6, 8 };

            arr = arr.Distinct().ToArray();

            foreach (var item in arr)
                Console.Write(item.ToString() + " ");
        }
    }
}

/*
run:
    
1 2 3 5 6 8
   
*/

 

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