Quickest way to enumerate the alphabet

Question

I want to iterate over the alphabet like so:

foreach(char c in alphabet)
{
 //do something with letter
}

Is an array of chars the best way to do this? (feels hacky)

Edit: The metric is "least typing to implement whilst still being readable and robust"

Subcommittee

Anytime you ask a "best" question, you need to give metrics to evaluate against or else everyone is going to throw specific answers out which likely do not apply to your unique situation. – Thermomotor

The only thing that may be hacky as you put it is that you are using a foreach loop instead of a standard for loop, but even then its not really hacky. – Importunate

I was looking for a "neater" way than enumerating over an array of chars. The metric is "least typing to implement whilst still being readable and robust" - Richard's answer is closest to my original thinking (which I couldn't articulate at the time of questioning) – Subcommittee

See #314966 #253162 – Subcommittee

Answer 1

(Assumes ASCII, etc)

for (char c = 'A'; c <= 'Z'; c++)
{
    //do something with letter 
} 

Alternatively, you could split it out to a provider and use an iterator (if you're planning on supporting internationalisation):

public class EnglishAlphabetProvider : IAlphabetProvider
{
    public IEnumerable<char> GetAlphabet()
    {
        for (char c = 'A'; c <= 'Z'; c++)
        {
            yield return c;
        } 
    }
}

IAlphabetProvider provider = new EnglishAlphabetProvider();

foreach (char c in provider.GetAlphabet())
{
    //do something with letter 
} 

Cindiecindra

Woah...never thought of that. Brilliant! – Resinous

If you neeeeed foreach: Enumerable.Range('a', 'z'-'a' + 1).Select(x=>(char)x) – Jorin

@Richard: You just give half of the solution. I like your generic IAlphabetProvider approach, but you need a factory to get the correct provider. Something like: var provider = AlphabetProvider.GetProvider(CultureInfo.CurrentCulture); – Yacov

It's just sample code, I can't write the entire application in my answer. FYI by having a static method, your solution is coupled to the AlphabetProvider class. – Cindiecindra

@Rob - you can replace that Select with Cast<char>. – Doyon

@Richard Szalay & Rob Fonseca-Ensor: you should add your input to the "Hidden Features of C#" meta-question. Those things are gems! Here's a link to the question: https://mcmap.net/q/16352/-hidden-features-of-c-closed – Erzurum

@Rob - argh! I forgot that normal casts don't work between generic parameters. If you write your own version of Cast, you find the compiler won't accept it unless you cast to object first. Which makes it a boxing conversion, so you can only get out exactly whatever you put in. So I withdraw my comment. – Doyon

(Although I think it will work in C# 4.0, just installing it now to find out.) – Doyon

Results are mixed... a generic cast via dynamic will work. But Enumerable.Cast still does an old-style unboxing, so no change there. But it is very easy to write a similar DynamicCast extension that says yield return (TOut)(dynamic)item, and that works. – Doyon

It will be really great if you can add the interface's definition public interface IAlphabetProvider { IList<string> GetAlphabet(); } as well into your post for clarity as it is a user defined interface. Prima facie it looks as if IAlphabetProvider is an already existing interface in .Net framework class library and you have simply implemented it to solve OP's problem. – Ballista

@Ballista - Tbh, the core of my answer was that you can do for loops on char values. The rest of it was just potential design inspiration if the OP wanted to take it further. – Cindiecindra

I understand your point @RichardSzalay. I suggested as it would bring completeness to your post and will be more clearer for the future readers also. For a second one gets lost as from where this interface IAlphabetProvider is coming from. – Ballista

Answer 2

Or you could do,

string alphabet = "abcdefghijklmnopqrstuvwxyz";

foreach(char c in alphabet)
{
 //do something with letter
}

Parapsychology

With this solution, internationalization is easy: use different letters :) (assuming C#'s foreach char goes by letter rather than 8-bit sequence). If it doesn't, I don't know the best approach for multi-byte characters in C#. – Cobweb

@JoeyAdams For internationalization, would you take the hard-coded literal out of the code and get it through the ResourceManager or something? – Pifer

@JoeyAdams String.GetEnumerator() goes char by char, so you’d only have a partial Unicode code point/surrogate pair if your string contains such characters. So you might want to normalize both your alphabet and the data you are comparing against it and ensure you think in terms of numeric codepoints rather than char: https://mcmap.net/q/243197/-how-would-you-get-an-array-of-unicode-code-points-from-a-net-string – Skied

Answer 3

var alphabet = Enumerable.Range(0, 26).Select(i => Convert.ToChar('A' + i));

Cohere

Answer 4

Enumerable.Range(65, 26).Select(a => new { A = (char)(a) }).ToList().ForEach(c => Console.WriteLine(c.A));

Shinleaf

Not much point newing-up an anonymous object to store a single property. And the built-in foreach statement is usually clearer for performing an action on each item of a sequence - that's what it's for. – Doyon

To simplify: Enumerable.Range(65, 26).ToList().ForEach(c => Console.WriteLine((char)c)); – Iddo

Nice; This saved me some time ! – Censurable

Answer 5

Use Enumerable.Range:

Enumerable.Range('A', ('Z' - 'A' + 1)).Select(i => (char)i)

Andriaandriana

Answer 6

You could do this:

for(int i = 65; i <= 95; i++)
{
    //use System.Convert.ToChar() f.e. here
    doSomethingWithTheChar(Convert.ToChar(i));
}

Though, not the best way either. Maybe we could help better if we would know the reason for this.

Resinous

Answer 7

I found this:

foreach(char letter in Enumerable.Range(65, 26).ToList().ConvertAll(delegate(int value) { return (char)value; }))
{
//breakpoint here to confirm
}

while randomly reading this blog, and thought it was an interesting way to accomplish the task.

Baton

I hope this was a joke. Really :) – Electroshock