CODEWITHSUNDEEP
c#stringsearch
xDevil
xDevil

Reputation: 147

Number of occurrences of a character in a string and their positions

Console.WriteLine("Insert the character you are searching for: ");
CharacterSearch = Console.ReadLine();
var count = file.Where(x => x == CharacterSearch).Count();

So what I am trying to do is to read text from the variable file and then search for a specific character in the string that is entered from the keyboard. So the searched character would be CharacterSearch.

I also want to check for their positions not just the number of occurrences.

Upvotes: 1

Views: 211

Answers (3)

Mike Perrenoud
Mike Perrenoud

Reputation: 67898

This is very inefficient, but it's an option is the files are small.

CharacterSearch = Console.ReadKey();
var count = File.ReadLines(pathToFile)
    .Select((c, i) => new { Character = c, Index = i })
    .ToList()
    .Where(x => x.Character == CharacterSearch);

Upvotes: 1

Sameer
Sameer

Reputation: 3183

Inefficient but can be applied if file is small.

public static int CharCount(string input,char c)
{
    var charCount=input.GroupBy(a => a).ToDictionary(k => k.Key, v => v.Count());
    if (charCount.ContainsKey(c))
        return charCount[c];
    return 0;
}

If you want to do the search over an over in the same string, i think it is better maintain a mapping. Again considerable only for a small file.

 public static Dictionary<char, int> CharCountMapping(string input)
{
    return input.GroupBy(a => a).ToDictionary(k => k.Key, v => v.Count());
}

Upvotes: 0

Hossein Narimani Rad
Hossein Narimani Rad

Reputation: 32481

Why not simply use this method? (Are you looking for a complicated one?)

List<int> indexes = new List<int>();

for (int i = 0; i < file.Length; i++)
{
    if (file[i]==CharacterSearch)
    {
        indexes.Add(i);    
    }
}

int count = indexes.Count;

Upvotes: 1

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