Splitting string into pairs with c#

Question

Is there a way to break a string into pairs without looking at indexes? e.g. TVBMCVTVFGTVTB would be broken into a list of strings as such:

[TV,BM,CV,TV,FG,TV,TB]

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Answer 1

Convert the string into a char array and then iterate along that making new strings out of pairs of characters.

Answer 2

If you like some esoteric solutions:

1)

string s = "TVBMCVTVFGTVTB";
var splitted = Enumerable.Range(0, s.Length)
                         .GroupBy(x => x / 2)
                         .Select(x => new string(x.Select(y => s[y]).ToArray()))
                         .ToList();

2)

string s = "ABCDEFGHIJKLMN";
var splitted = Enumerable.Range(0, (s.Length + 1) / 2)
                         .Select(i => 
                                 s[i * 2] + 
                                 ((i * 2 + 1 < s.Length) ? 
                                 s[i * 2 + 1].ToString() : 
                                 string.Empty))
                         .ToList();

Answer 3

If you REALLY want to avoid using indexes...

You could use a Regex "\w\w" or "\w{2,2}" or some variation like that and MSDN - Regex.Matches method to get a MatchCollection which would contain the matches as pairs of characters. Change \w in the regex pattern to suit your needs.

Answer 4

List<string> result = new List<string>();

while (original.Length > 0)
{
    result.Add(new String(original.Take(2).ToArray()));
    original = new String(original.Skip(2).ToArray());
}

return result;

The LINQ probably uses indices somewhere internally, but I didn't touch any of them so I consider this valid. It works for odd-length originals, too.

Edit:

Thanks Heinzi for the correction. Demo: http://rextester.com/MWCKYD83206

Answer 5

1) Split list into pairs

var s = "TVBMCVTVFGTVTB";
var pairs = Enumerable.Range(0, s.Length / 2)
                      .Select(i => String.Concat(s.Skip(i * 2).Take(2)));

This will work if you know that s always is of even length, or you don't accept, or don't care about, ending with singletons for strings with odd length.

2) Split list into pairs - include any singleton remainders

If you want to include singleton remainders, for odd length strings, you can simply use ceiling:

var s = "TVBMCVTVFGTVTB";
var pairs = Enumerable.Range(0, (int)Math.Ceiling(s.Length / 2D))
                      .Select(i => String.Concat(s.Skip(i * 2).Take(2)));

Answer 6

Oh come on, just use indexes like this:

public static class StringExtensions {
    public static IEnumerable<string> TakeEvery(this string s, int count) {
        int index = 0;
        while(index < s.Length) {
            if(s.Length - index >= count) {
                yield return s.Substring(index, count);
            }
            else {
                yield return s.Substring(index, s.Length - index);
            }
            index += count;
        }
    }
}

I have added no guard clauses.

Usage:

var items = "TVBMCVTVFGTVTB".TakeEvery(2);
foreach(var item in items) {
    Console.WriteLine(item);
}