Question: I'm working on a Kata on CodeWars in which I have to count the amount of repetitions each letter has in a string. The amount of repetitions should be stored in an int array.

The algorithm I've written seems to almost work, however I get a weird output that I can't explain. I might be missing something in the code.

```
static void Main(string[] args)
{
    string str = "abcdef";
    string input = str.ToLower();
    int count = 0;

    string[] arrayInput = Regex.Split(input, string.Empty);
    string[] alphabet = Regex.Split("abcdefghijklmnopqrstuvwxyz", string.Empty);
    int[] amounts = new int[input.Length];

    foreach (string letter in alphabet)
    {
        for (int x = 0; x < input.Length; x++)
        {
            if (arrayInput[x] == letter)
            {
               amounts[x]++;
            }
        }
    }

    foreach (int amount in amounts)
    {
        Console.Write(amount + ", ");
    }
    Console.ReadKey();
}

```

Output: 

> 
> "2, 1, 1, 1, 1, 1,"
> 
> 
> 

Expected: 

> 
> "1, 1, 1, 1, 1, 1,"
> 
> 
> 

since each letter only appears once in the string.

Answer: 
There are a lot of different approaches, but when it comes to counting of some limited number of items Dictionary is almost always the best choice in terms of performance. The below code is pretty low level if compared to solutions using LINQ, but that's what I like about that: you always control what happens there.

```
string str = "abcdef";
string input = str.ToLower();

var dict = "abcdefghijklmnopqrstuvwxyz".ToDictionary(k => k, v => 0);

foreach (char c in input)
{
    dict[c]++;
}

var output = new int[dict.Count];   
var index = 0;

foreach (var key in dict.Keys.OrderBy(k => k))
{
    output[index++] = dict[key];
}

```

In case you want to visualize how the dictionary with counts looks, you can add the following output:

```
foreach (var key in dict.Keys)
{
    Console.WriteLine($"Key {key} Value {dict[key]}");
}

```
When you print the values after the split you will observer the extra space. It seems that is causing issue.

```js
using System;
using System.Text.RegularExpressions;     
public class Program
{
 public static void Main()
 {
    string str = "abcdef";
    string input = str.ToLower();
    int count = 0;

    char[] arrayInput = input.ToCharArray();
    char[] alphabet = "abcdefghijklmnopqrstuvwxyz".ToCharArray();
    int[] amounts = new int[input.Length];

 foreach (char letter in alphabet)
 Console.Write(letter + ", ");
 // observe the first letter here when you use regx.split
 //, a, b, c, d, e, f, g, h, i, j, k, l, m, n, o, p, q, r, s, t, u, v, w, x, y, z, 

 foreach (char inputWord in arrayInput)
 Console.Write(inputWord + ", ");
 // you get extra space in the start hence there is issue when you use regx.split
 //, a, b, c, d, e, f,

    foreach (var letter in alphabet)
    {
        for (int x = 0; x < input.Length; x++)
        {
            if (arrayInput[x] == letter)
            {
               amounts[x] = amounts[x] + 1;
            }
        }
    }

    foreach (int amount in amounts)
    {
        Console.Write(amount + ", ");
    }

 }
}
```

stick to basic: use string.ToCharArray()