How do I find duplicates in an char array

Question

1.00/5 (1 vote)

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Basically i have a char array and i want to be able to count the number of duplicates from it.

Edit
Basically i was trying to make the terminal game from fallout. A pass-code will be entered and people will try to guess it. When guessing you will be told how many of these letters are correct and whether the length of the word is correct.

I use this to convert the actual word to an array

char[] ActualChar = new char[WordLenght];

            while (ApproachingLenght < WordLenght) 
            {
                foreach (char Letter in Word)
                { 
                    ActualChar[ApproachingLenght] = Letter;
                    ApproachingLenght++;
                }
            }

Guess into array

char[] GuessChar = new char[GuessLenght];
            while (ApproachingGuessLenght < GuessLenght)
            {
                foreach (char Letter in Guess)
                {
                    GuessChar[ApproachingGuessLenght] = Letter;
                    ApproachingGuessLenght++;
                }
            }

This to check for similarities between the two arrays, HOWEVER i get a problem here basically if the actual word is "Hello" and guess "Helli" it will say 6 characters are similar rather than 4. I found the problem to be the 2 l's as "abcd, asdf" did not have this issue.

if(GuessLenght == WordLenght)
            {
                //Check Each Element


                for (int i = 0; i < WordLenght; i++)
                {
                    for(int p = 0; p < WordLenght; p++)
                    {
                        if (GuessChar[i] == ActualChar[p])
                        {
                            LetterGuessed++;
                        }
                    }
                }
                
            }
            else
            {
                if(GuessLenght> WordLenght)
                {
                    Console.WriteLine("Wrong Lenght, Actual Lenght is : Shorter");
                }
                else
                {
                    Console.WriteLine("Wrong Lenght, Actual Lenght is : Longer");
                }
            }

Therefore i planned to find the number of duplicates in the array and minus it from the letters guessed.

What I have tried:

string longText = @"your sentence comes here";
    foreach (var character in CharacterCount.Count(longText))
    {
        if(character.Value>1)
           Console.WriteLine("{0} - {1}", character.Key, character.Value);
    }

This i found online and just added it.

Posted 12-May-20 11:10am

NotAComputerScienceStudent

Updated 12-May-20 23:27pm

v3

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Comments

Afzaal Ahmad Zeeshan 12-May-20 18:12pm

What is this CharacterCount.Count method?

PIEBALDconsult 12-May-20 18:24pm

Unclear.
How many characters are duplicated?
Or how many total duplicate characters there are?
Please provide sample input and output.

PIEBALDconsult 13-May-20 19:00pm

Having seen your edit... Have a re-think. You needn't focus on duplicates.
But I still don't understand the goal, all I know is that F("Hello","Helli") is _not_ 6.

4 solutions

Solution 3

var uniqueChars = longText.Distinct();

foreach (var ch in uniqueChars)
{
    Console.WriteLine(
        $"char: {ch} char ascii value: {(int)ch} instances: {longText.Count(c => c == ch)}\r\n");
}

Console.WriteLine($"nduplicates: {longText.Count() - uniqueChars.Count()}");

character.Key and character.Value are not C#.

Posted 12-May-20 20:08pm

BillWoodruff

Updated 12-May-20 21:10pm

v2

Comments

Maciej Los 13-May-20 2:39am

5ed!

Solution 2

Well, if you do it this way, you'll get kicked out of class:

C#

System.Text.RegularExpressions.Regex reg =
  new System.Text.RegularExpressions.Regex
  (
    @"(?i)^
    ((?'A'A)|(?'B'B)|(?'C'C)|(?'D'D)|(?'E'E)
    |(?'F'F)|(?'G'G)|(?'H'H)|(?'I'I)|(?'J'J)
    |(?'K'K)|(?'L'L)|(?'M'M)|(?'N'N)|(?'O'O)
    |(?'P'P)|(?'Q'Q)|(?'R'R)|(?'S'S)|(?'T'T)
    |(?'U'U)|(?'V'V)|(?'W'W)|(?'X'X)|(?'Y'Y)
    |(?'Z'Z)|(?'Other'.))*$"
  ,
    System.Text.RegularExpressions.RegexOptions.Compiled
    |
    System.Text.RegularExpressions.RegexOptions.ExplicitCapture
    |
    System.Text.RegularExpressions.RegexOptions.IgnorePatternWhitespace
  ) ;

string[] n = reg.GetGroupNames() ;

System.Text.RegularExpressions.MatchCollection mat =
  reg.Matches ( "The quick brown fox jumps over the lazy dog." ) ;

for ( int i = 0 ; i < mat.Count ; i++ )
{
  for ( int g = 1 ; g < n.Length ; g++ )
  {
    System.Console.WriteLine ( "{0} {1}" , n [ g ] , mat [ i ] .Groups [ n [ g ] ].Captures.Count ) ;
  }
}

Posted 12-May-20 15:24pm

PIEBALDconsult

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AnkushK1 · Accepted Answer · 2020-05-12T14:07:00

Solution 1

var duplicateDict = new Dictionary<char, int>();
		string longText = @"your sentence comes here";
		foreach (var ch in longText)
		{
			if (duplicateDict.ContainsKey(ch))
			{
				duplicateDict[ch]++;
			}
			else
			{
				duplicateDict.Add(ch, 1);
			}
		}

		foreach (var ch in duplicateDict.Where(x => x.Value > 1))
		{
			Console.WriteLine(string.Format("Duplicate Character {0}, Count {1}", ch.Key, ch.Value));
		}

Posted 12-May-20 14:07pm

AnkushK1

Comments

PIEBALDconsult 12-May-20 20:24pm

Best not to do peoples' homework for them.
And that can be improved.

Maciej Los 13-May-20 2:40am

Dictionary is good idea!
5ed!

NotAComputerScienceStudent 13-May-20 4:59am

isn't homework i have nothing better to do in quarantine, i'm a mechanics student.

Maciej Los 13-May-20 5:40am

Sorry, but you have replied to wrong person...
BTW: Have ou seen my solution?

Maciej Los · Accepted Answer · 2020-05-12T20:49:00

Solution 4

If you would like to get only duplicates...

C#

string longText = @"your sentence comes here";
Dictionary<char, int> result = longText
	.GroupBy(x=>x)
	.Select(grp => new KeyValuePair<char, int>(grp.Key, grp.Count()))
	.Where(kvp=> kvp.Value>1)
	.OrderByDescending(kvp=> kvp.Value)
	.ToDictionary(kvp=> kvp.Key, kvp=>kvp.Value);
	
foreach(KeyValuePair<char, int> kvp in result)
	Console.WriteLine($"'{kvp.Key}' => {kvp.Value}" );

Posted 12-May-20 20:49pm

Maciej Los

Comments

Maciej Los 13-May-20 5:52am

You mean namespace: System.Linq
See: Enumerable.GroupBy Method (System.Linq) | Microsoft Docs[^]

NotAComputerScienceStudent 13-May-20 5:53am

It worked

Maciej Los 13-May-20 5:54am

I'm glad.
Does it solves your issue?