how to have a list of 'a' to 'z'?

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I have a code that I want to count the number of appearing each letter in alphabet in the input string. I used a dictionary<char, int> to have a key for each letter and a value as the count of appearance. So, how to have a list of 'a' to 'z' to use as keys? I've tried this:

Dictionary<char, int> alphabetCounter = new Dictionary<char, int>();
for (char ch = 'a'; ch <= 'z'; ch++)
    alphabetCounter[ch] = 0;

Is it a better way to have the list of 'a' to 'z'? Thank you.

c#
4 Answers

Using Linq try this to have a list from "a" to "z".

var list = Enumerable.Range('a', 'z' - 'a' + 1).Select(c => (char)c).ToList();

If you want to get in upper case, is the same but using upper case.

var list = Enumerable.Range('A', 'Z' - 'A' + 1).Select(c => (char)c).ToList();

Edit:

Your question is to get the list, but to get as dictionary you can use .ToDictionary() and initialize with value 0:

var dictionary = Enumerable.Range('a', 'z' - 'a' + 1).Select(c => (char)c).ToDictionary(i => (char)i, i => 0);

The same case to upper/lower case.

user_134642790

Here's a way to do it in LINQ:

var alphabetCounter = Enumerable.Range(97, 26).ToDictionary(i => (char)i, i => 0);

This will create a dictionary with all chars with values 0.

ASCII codes of alphabet (lowercase) begins at 97, we can then take 26 numbers from there and convert them to char.

user_54470840

Is performance a thing? You can keep it simple.
You do not need to create your own dictionary, register every possibility then start counter[i]++ for each ocurrence, seems a bit of an overkill to me.

You can group up the letters by using .GroupBy (System.Linq), then after you can check the count of each ocurrence.

Example:

var word = "test";
var groupedLetters = word.GroupBy(x => x);

foreach(var letter in groupedLetters)
{
    Console.WriteLine($"{letter.Key} - {letter.Count()}");
}

Output:

t - 2  
e - 1  
s - 1
user_82423250

Hi May this example will help :

List<char> LS = new List<char>() {'A', 'B', 'C', 'D', 'A', 'D', 'B', 'A'};
Dictionary<char,int> AlphaDictionary = (from x in LS group x by x).Select(x => new {Alpha = x.Key, Count = x.Count()}).ToDictionary(x=>x.Alpha,x=>x.Count);
user_145215650
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