How to check repeated letters in a string c#

count number of duplicate characters in a string java
how to print duplicate characters from string in python
repeated string c
duplicate characters in a string php
how to count repeated characters in a string php
count consecutive characters in a string c
print the duplicate characters from the given string in java
python program to remove duplicate characters from a string

I am creating a program that checks repeated letters in a string.

For Example:


This is my code:

 string repeatedWord = "woooooooow";
 for (int i = 0; i < repeatedWord.Count(); i++)
     if (repeatedWord[i] == repeatedWord[i+1])
          // ....

The code works but it will always have an error because the last character [i + 1] is empty/null.

The error is Index was outside the bounds of the array.

Any solution for this?

run the loop until repeatedWord.Count()-1

Program to Find the Duplicate Characters in a String, How do you check if a character is repeated in a string Javascript? 1. We loop through the string and hash the characters using ASCII codes. Store 1 if found and store 2 if found again. Also, store the position of the letter first found in. 2. We run a loop on the hash array and now we find the minimum position of any character repeated. This will have a runtime of O(N).

Another option would be using a Regex that matches repeating characters. Then, for each match, you can obtain the number of characters by using the Length property.

string input = "wooooooow happppppppy";
var matches = Regex.Matches(input, @"(.)\1+");
for (int i = 0; i < matches.Count; i++)
    Console.WriteLine("\"" + matches[i].Value + "\" is " + matches[i].Length + " characters long.");

Check for repeated characters in a string Javascript, . var example = 'hello'; var charRepeats = function(str) { for (var i=0; i<str. Now you can check if a character exists in the dictionary each time you come across it, and either add it or increment the count. Secondly, your code doesn't check for letters at all, it just loops on the strings in the array, and copies them into a dictionary, using the array index as the count - which is completely pointless.

Regular Expression:

Regex rxContainsMultipleChars = new Regex( @"(?<char>.)\k<char>" , RegexOptions.ExplicitCapture|RegexOptions.Singleline ) ;
string myString = SomeStringValue() ;
bool containsDuplicates = rxDupes.Match(myString) ;

or Linq

string s = SomeStringValue() ;
bool containsDuplicates = s.Where( (c,i) => i > 0 && c == s[i-1] )
                           .FirstOrDefault() != null

or roll yer own:

public bool ContainsDuplicateChars( string s )
  if ( string.IsNullOrEmpty(s) ) return false ;

  bool containsDupes = false ;
  for ( int i = 1 ; i < s.Length && !containsDupes ; ++i )
    containsDupes = s[i] == s[i-1] ;

  return containsDupes ;

Or even

public static class EnumerableHelpers
  public static IEnumerable<Tuple<char,int>> RunLengthEncoder( this IEnumerable<char> list )
    char? prev  = null ;
    int   count = 0 ;

    foreach ( char curr in list )
      if      ( prev == null ) { ++count ; prev = curr ; }
      else if ( prev == curr ) { ++count ;               }
      else if ( curr != prev )
        yield return new Tuple<char, int>((char)prev,count) ;
        prev = curr ;
        count = 1 ;

With this last one...

bool hasDupes = s.RunLengthEncoder().FirstOrDefault( x => x.Item2 > 1 ) != null ;


foreach (Tuple<char,int> run in myString.RunLengthEncoder() )
  if ( run.Item2 > 1 )
     // do something with the run of repeated chars.

Find repeated character present first in a string, How do I print the first repeated character in a string? Basically, it checks if a pattern of one or more characters appears 3 or more times in the same string. Full explanation: First, it matches 0 or more characters at the beginning of the string. Then it captures a group of one or more. Then it matches 0 or more, and then the group again. Then 0 or more again, and then the capture again. Then 0 or more again.

Just "remember" the last letter i would say.

string repeatedWord = "woooooooow";
if (string.IsNullOrEmpty( repeatedWord))
    // empty. return, throw whatever.

char previousLetter = repeatedWord[0]; 
for (int i = 1; i < repeatedWord.Count(); i++)
    if (repeatedWord[i] == previousLetter)
        // ....              
    previousLetter = repeatedWord[i];

Count occurrences of a character in a repeated string, How do you count the number of occurrences of a character in a string in C? How to check repeated letters in a string c#. Ask Question Asked 6 years, 8 months ago. To find duplicate or repeated letters in given string using C#.

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace Delegate
    class Program
       public int repeatcount(string str,char ch)

            var count = 0;
            for (int i = 0; i<str.Length; i++)
                if (ch == str[i])


            return count;
        static void Main(string[] args)
            Console.WriteLine("Enter a string");
            string str = Console.ReadLine();
            Console.WriteLine("Enter to know the reperted char");
            char ch = Convert.ToChar(Console.ReadLine());
            Program obj = new Program();
            int p=obj.repeatcount(str, ch);




How to print duplicate characters in a String using C#?, distinct characters · Print string after removing all (“10” or “01”) from the binary string · Check whether an array of strings can correspond to a Given a string, find the repeated character present first in the string. C# program to find the fist character We loop through the string and hash the characters using ASCII codes. public static bool OnlyOnceCheck(string input) { return input.Distinct().Count() == input.Length; } Update. If someone is afraid about performance, you can always get a little better with HasSet<char>: public static bool OnlyOnceCheck(string input) { var set = new HashSet<char>(); return input.Any(x => !set.Add(x)); }

How to find the most repeated character in a string in C#.NET , int countChar(string str, char x). {. int count = 0 check for the remaining repeating character. for ( int i = 0; C# program to find the occurrences. // of character x  To find the duplicate character from the string, we count the occurrence of each character in the string. If count is greater than 1, it implies that a character has a duplicate entry in the string. In above example, the characters highlighted in green are duplicate characters.

C# Program to find number of occurrence of a character in a String , Set maximum value for char. static int maxCHARS = 256; Now display the duplicate characters in the string. String s = Welcometomywebsite! If the char already exists in the result, it is a duplicate—we do not need to append it again. IndexOf: The IndexOf method in the RemoveDuplicateChars method is notable here. If the specific character is not found, it returns -1. IndexOf. Note: Thanks to Nicolas Siatras for helping improve the string-based method here. Only 1 string is needed in the method.

[Solved] How to check count of repeating letters in an array using , In this video, I will show you how to use Visual Studio to write a C#.NET program to display the Duration: 4:32 Posted: Nov 14, 2016

  • repeatedWord.Count() - 1
  • It is pretty clear: you cannot iterate until the last position if you look for +1 index. repeatedWord.Count() - 1 should be the maximum value.
  • If you have an array that is 10 elements long, you can't attempt to read the 11th element. Have you stepped through your 'for' loop in a debugger to see what's happening?
  • Are you looking for sequential repetition or any character repetition in the entire string? Also are you interested to know the actual character which is repeated, or just want a bool result?
  • What is your goal? Do you want to get the number of repeated characters? It is not clear that what your objective is.
  • You'll miss the last letter?
  • @JeroenvanLangen And you want to check the last letter against what exactly? It will always be different than 'end of line'.
  • @JeroenvanLangen new[] { 0, 1, 2 }.Count() == 3
  • True, true, the last letter = [i+1] missed that... ;) i'd rather avoid index+1 in code. will be less readable and forces programmers to use things like count-1 etc. So could cause more "strange" behaviour
  • You need to start at the second char if you do this, otherwise you'll fail for looking to the char just before the first.
  • hello timothy! can you please explain how does the code do it
  • In the count, we can get the repeated characters value
  • better you explain more detail
  • @I4V You're right. This isn't constrained to sequential repeats.