所以我在做一个面试时，得到了同样的问题来分类和区分

static void Sort()
    {
        try
        {
            int[] number = new int[Convert.ToInt32(Console.ReadLine())];
            for (int i = 0; i < number.Length; i++)
            {
                number[i] = Convert.ToInt32(Console.ReadLine());
            }
            Array.Sort(number);
            int[] num = number.Distinct().ToArray();
            for (int i = 0; i < num.Length; i++)
            {
                Console.WriteLine(num[i]);
            }
        }
        catch (Exception ex)
        {
            Console.WriteLine(ex);
        }
        Console.Read();
    }

protected void Page_Load(object sender, EventArgs e)
{
    string a = "a;b;c;d;e;v";
    string[] b = a.Split(';');
    string[] c = b.Distinct().ToArray();

    if (b.Length != c.Length)
    {
        for (int i = 0; i < b.Length; i++)
        {
            try
            {
                if (b[i].ToString() != c[i].ToString())
                {
                    Response.Write("Found duplicate " + b[i].ToString());
                    return;
                }
            }
            catch (Exception ex)
            {
                Response.Write("Found duplicate " + b[i].ToString());
                return;
            }
        }              
    }
    else
    {
        Response.Write("No duplicate ");
    }
}

下面经过测试和工作的代码将从数组中删除重复项。你必须包括系统。集合名称空间。

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]);
}

如果你愿意，你可以把它打包成一个函数。

下面是HashSet<string>方法:

public static string[] RemoveDuplicates(string[] s)
{
    HashSet<string> set = new HashSet<string>(s);
    string[] result = new string[set.Count];
    set.CopyTo(result);
    return result;
}

不幸的是，这个解决方案也需要。net框架3.5或更高版本，因为HashSet直到该版本才被添加。你也可以使用array.Distinct()，这是LINQ的一个特性。

using System;
using System.Collections.Generic;
using System.Linq;


namespace Rextester
{
    public class Program
    {
        public static void Main(string[] args)
        {
             List<int> listofint1 = new List<int> { 4, 8, 4, 1, 1, 4, 8 };
           List<int> updatedlist= removeduplicate(listofint1);
            foreach(int num in updatedlist)
               Console.WriteLine(num);
        }


        public static List<int> removeduplicate(List<int> listofint)
         {
             List<int> listofintwithoutduplicate= new List<int>();


              foreach(var num in listofint)
                 {
                  if(!listofintwithoutduplicate.Any(p=>p==num))
                        {
                          listofintwithoutduplicate.Add(num);
                        }
                  }
             return listofintwithoutduplicate;
         }
    }



}

测试了下面的&它工作。最酷的是，它还做了一个文化敏感搜索

class RemoveDuplicatesInString
{
    public static String RemoveDups(String origString)
    {
        String outString = null;
        int readIndex = 0;
        CompareInfo ci = CultureInfo.CurrentCulture.CompareInfo;


        if(String.IsNullOrEmpty(origString))
        {
            return outString;
        }

        foreach (var ch in origString)
        {
            if (readIndex == 0)
            {
                outString = String.Concat(ch);
                readIndex++;
                continue;
            }

            if (ci.IndexOf(origString, ch.ToString().ToLower(), 0, readIndex) == -1)
            {
                //Unique char as this char wasn't found earlier.
                outString = String.Concat(outString, ch);                   
            }

            readIndex++;

        }


        return outString;
    }


    static void Main(string[] args)
    {
        String inputString = "aAbcefc";
        String outputString;

        outputString = RemoveDups(inputString);

        Console.WriteLine(outputString);
    }

}

--AptSenSDET