How to get distinct characters?

I have a code like

string code = "AA开发者_开发问答BBDDCCRRFF";

In this code, I want to retrieve only distinct characters

The Output should be like:

ANS: ABDCRF

string code = "AABBDDCCRRFF";
string answer = new String(code.Distinct().ToArray());

Linq's Distinct returns distinct elements from a sequence. As the String class implements IEnumerable<char>, Distinct in this context returns an IEnumerable<char> containing all of the unique characters in the string.

code.Distinct();

Alternative option using dotNet 2.0 compatible code:

public string RemoveDuplicateChars(string input)
{
    var stringBuilder = new StringBuilder(input);

    foreach (char c in input)
    {
        stringBuilder.Replace(c.ToString(), string.Empty)
                     .Append(c.ToString());
    }

    return stringBuilder.ToString();
}

Here's an approach that provides the string and a count of the distinct characters...

using System;
using System.Collections.Generic;

namespace StringDict
{
    class Program
    {
        static IDictionary<char, int> charDict =new Dictionary<char, int>();
        static private string _charStr = "s;ldfjgsl;dkkjfg;lsdkfjg;lsdkfjg;lsdkfjg;lsdkfj";
        private static int _outInt=0;
        static void Main(string[] args)
        {
            foreach (var ch in _charStr)
            {
                if (!charDict.TryGetValue(ch,out _outInt))
                {
                    charDict.Add(new KeyValuePair<char, int>(ch,1));
                }
                else
                {
                    charDict[ch]++;
                }
            }
            Console.Write("Unique Characters: ");
            Console.WriteLine('\n');
            foreach (var kvp in charDict)
            {
                Console.Write(kvp.Key);
            }
            Console.WriteLine('\n');
            foreach (var kvp in charDict)
            {
                Console.WriteLine("Char: "+kvp.Key+" Count: "+kvp.Value);
            }
            Console.ReadLine();
        }
    }
}

Output...

Unique Characters:

s;ldfjgk

Char: s Count: 6
Char: ; Count: 6
Char: l Count: 6
Char: d Count: 6
Char: f Count: 6
Char: j Count: 6
Char: g Count: 5
Char: k Count: 6

How about in linq:

var str = "AABBCCDDDDDDEEEEEFFF";
var unique = str.ToCharArray().Distinct();
Console.WriteLine("Answer: {0}.", string.Join(string.Empty, unique));

You can do this as follows

var s = "AABBDDCCRRFF";
var result = s.Distinct();
var distinct = result.Aggregate(string.Empty, (current, c) => current + c.ToString());
Console.WriteLine(distinct);

Here's an approach with grouping by characters...

var code="AABBDDCCRRFF";
var unique = string.Concat(text.GroupBy(a => a).Select(a => a.Key));

To get all distinct characters I have used ascii array. steps 1. Added ascii array of size 256, becuase max char ascii value is 255 step 2. increment each ascii to the location of particular alphabet's ascii value

please refer below code to understand.

public static class StringManipulation
{
  public static string UniqueChars(this string astrInputString)
  {
       astrInputString = astrInputString.ToLower();
    int[] arrAscii = new int[256];
    string lstrFinalOutput = string.Empty;
    for (int i = 0; i < astrInputString.Length; i++)
    {
        arrAscii[Convert.ToInt32(astrInputString[i])]++;
    }

    for (int i = 0; i < astrInputString.Length; i++)
    {
        if (arrAscii[Convert.ToInt32(astrInputString[i])] == 1)
            lstrFinalOutput = lstrFinalOutput + astrInputString[i];
    }
    return lstrFinalOutput;
  }
}
class Program
{
  static void Main(string[] args)
  {
    string input = "AAssjjkkLLlx";
    Console.WriteLine("Unique Charcters in string " + input.UniqueChars());

  }
}

Click to Download this Code https://github.com/SiddharthBhamare/StringManipulation/blob/master/StringManipulation/Program.cs

Just for the heck of it -- using a StringBuilder

 string code = "AABBDDCCRRFF";
 StringBuilder sb = new StringBuilder();
 code.Distinct().ToList().ForEach(c => sb.Append(c));
 MessageBox.Show(sb.ToString());