CODEWITHSUNDEEP
c#regexstring
nGX
nGX

Reputation: 1068

Counting occurrences of specific letters in string

I have a string that looks like this:

3x3x3x204x4x4x6f

I want to read these letters in a row and want to count the amount of times I see the same pattern. For instance, I see that 3x happens 3 times. I want my counter to then reset and start from the position it ended on and if it sees a pattern again like the one above, give me count of repetitions.

I have tried this with no luck (I'm reading 2 characters at a time):

foreach (var set in splitString)
{
    currChars = set;

    if (!currChars.Contains(prevChars))
    {
        if (!currChars.Contains(_prevchars))
        {

        }
        newSet.Add(_prevchar);
        newSet.Add(occurrenceCount.ToString());
        newSet.Add("x");

        occurrenceCount = 0;
        newSet.Add(currChars);
    }
    else
    {
        occurrenceCount = occurrenceCount + 2;
        _prevchar = MethodX.StringManipulation.TruncateLongString(prevChars, 1);
        _prevchars = currChars;
    }
    prevChars = currChars;
}

Upvotes: 1

Views: 159

Answers (2)

Anirudha
Anirudha

Reputation: 32797

 var repeatList=Regex.Matches(input,@"(.+)(\1)+")
                .Cast<Match>()
                .Select(x=>
                   new { 
                        name = x.Groups[1].Value, 
                        count = x.Groups[2].Captures.Cast<Capture>().Count()+1 
                       }
                       );

You can now iterate

foreach(var repeat in repeatList)
{
    repeat.name;
    repeat.count;
}

Upvotes: 0

Rotem
Rotem

Reputation: 21917

Without using Regex, you can use the overload of String.IndexOf which accepts a starting position parameter. For every ocurrence of the pattern you find, increment the position accordingly and search again.

string s = "3x3x3x204x4x4x6f";
string pattern = "3x";
int count = 0;
int pos = 0;
while (true)
{
    int index = s.IndexOf(pattern, pos);
    if (index == -1) break;
    count++;
    pos = index + pattern.Length;       
}

    //count == 3

Upvotes: 2

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