Generating an array of letters in the alphabet

Question

Is there an easy way to generate an array containing the letters of the alphabet in C#? It's not too hard to do it by hand, but I was wondering if there was a built in way to do this.

Catharine

FYI, this question has been asked before with internationalization in mind. – Sailer

possible duplicate of Localization: How to map culture info to a script name or Unicode character range? – Prosciutto

The reverse can be found here https://mcmap.net/q/189528/-what-is-the-algorithm-to-convert-an-excel-column-letter-into-its-number – Cicely

Answer 1

I don't think there is a built in way, but I think the easiest would be

  char[] alpha = "ABCDEFGHIJKLMNOPQRSTUVWXYZ".ToCharArray();

Hufnagel

It also works on other alphabets, as long as you place the string in a Resource :) – Kokaras

This is the best way if you want to ensure that your code works on machines with different languages. Otherwise if you generate your alphabet dynamically (as other answers below) you can end with a different alphabet on different machines. – Xanthic

How does this work with different languages? Will this somehow magically contain chines letters, or letters form other languages? – Dorri

This answer almost seems like a joke answer. The OP specifically said he could do it by hand but wants an automated way. And it ignores culture, language, etc. – Ruff

Answer 2

C# 3.0 :

char[] az = Enumerable.Range('a', 'z' - 'a' + 1).Select(i => (Char)i).ToArray();
foreach (var c in az)
{
    Console.WriteLine(c);
}

yes it does work even if the only overload of Enumerable.Range accepts int parameters ;-)

Higdon

'z' - 'a' + 1 = It just looks really clumsy, but I can't see a way around it :( – Reef

String.Concat(Enumerable.Range('a', 'z' - 'a' + 1).Select(c => ((char)c).ToString().ToUpperInvariant())); returns ABCDEFGHIJKLMNOPQRSTUVWXYZ; – Napalm

@CasperT: Probably Enumerable.Range('a', 26) – Napalm

This won't work for the languages that have letters whose ASCII codes fall outside of the range 'a' - 'z'. You cannot use this method in such cases. Nice solution otherwise. – Phelps

Answer 3

for (char letter = 'A'; letter <= 'Z'; letter++)
{
     Debug.WriteLine(letter);
}

Fault

Pure and clean, thanks. – Witching

Answer 4

char[] alphabet = Enumerable.Range('A', 26).Select(asciiCode => (char)asciiCode).ToArray();

Atwater

Answer 5

I wrote this to get the MS excel column code (A,B,C, ..., Z, AA, AB, ..., ZZ, AAA, AAB, ...) based on a 1-based index. (Of course, switching to zero-based is simply leaving off the column--; at the start.)

public static String getColumnNameFromIndex(int column)
{
    column--;
    String col = Convert.ToString((char)('A' + (column % 26)));
    while (column >= 26)
    {
        column = (column / 26) -1;
        col = Convert.ToString((char)('A' + (column % 26))) + col;
    }
    return col;
}

Chrisom

Oh hey, just replacing Convert.ToString with String.valueOf makes it work in Java :) – Chrisom

How about getIndexFromColumnName ? – Liam

Answer 6

Assuming you mean the letters of the English alphabet...

    for ( int i = 0; i < 26; i++ )
    {
        Console.WriteLine( Convert.ToChar( i + 65 ) );
    }
    Console.WriteLine( "Press any key to continue." );
    Console.ReadKey();

Bight

It's better to use (int)'A' instead of hardcoding 65. It'll make the code more readable and less prone to errors. – Overspread

However, in the leading encoding where 'A' != 65, (EBCDIC), A to Z aren't sequencial. – Pilsudski

Doesn't look like an array to me. – Grate

@MehrdadAfshari Internally used encoding is irrelevant. What is relevant is that the values of type Char are Unicode code points, and those are A-Z sequential. – Chrisom

Answer 7

You could do something like this, based on the ascii values of the characters:

char[26] alphabet;

for(int i = 0; i <26; i++)
{
     alphabet[i] = (char)(i+65); //65 is the offset for capital A in the ascaii table
}

(See the table here.) You are just casting from the int value of the character to the character value - but, that only works for ascii characters not different languages etc.

EDIT: As suggested by Mehrdad in the comment to a similar solution, it's better to do this:

alphabet[i] = (char)(i+(int)('A'));

This casts the A character to it's int value and then increments based on this, so it's not hardcoded.

Extinguisher

This code has a minor error. i = 0 to < 27 includes 27 letters (array element 0, then elements 1 to 26). – Burleigh

You can make it even better: alphabet[i] = (char)(i + 'A'); Same result – Reef

Shouldn't it be char[] alphabet = new char[26];? – Guillerminaguillermo

Answer 8

Note also, the string has a operator[] which returns a Char, and is an IEnumerable<char>, so for most purposes, you can use a string as a char[]. Hence:

string alpha = "ABCDEFGHIJKLMNOPQRSTUVQXYZ";
for (int i =0; i < 26; ++i)
{  
     Console.WriteLine(alpha[i]);
}

foreach(char c in alpha)
{  
     Console.WriteLine(c);
}

Pilsudski

Answer 9

Surprised no one has suggested a yield solution:

public static IEnumerable<char> Alphabet()
{
    for (char letter = 'A'; letter <= 'Z'; letter++)
    {
        yield return letter;
    }
}

Example:

foreach (var c in Alphabet())
{
    Console.Write(c);
}

Lightless

Answer 10

var alphabets = Enumerable.Range('A', 26).Select((num) => ((char)num).ToString()).ToList();

Perfidy

Answer 11

char alphaStart = Char.Parse("A");
char alphaEnd = Char.Parse("Z");
for(char i = alphaStart; i <= alphaEnd; i++) {
    string anchorLetter = i.ToString();
}

Westerman

It seems you have not learned how to use the correct quotes for chars. There is no reason to parse that from string; just use char alphaStart = 'A';, with single quotes instead of double quotes. – Chrisom

Answer 12

//generate a list of alphabet using csharp
//this recurcive function will return you
//a string with position of passed int
//say if pass 0 will return A ,1-B,2-C,.....,26-AA,27-AB,....,701-ZZ,702-AAA,703-AAB,...

static string CharacterIncrement(int colCount)
{
    int TempCount = 0;
    string returnCharCount = string.Empty;

    if (colCount <= 25)
    {
        TempCount = colCount;
        char CharCount = Convert.ToChar((Convert.ToInt32('A') + TempCount));
        returnCharCount += CharCount;
        return returnCharCount;
    }
    else
    {
        var rev = 0;

        while (colCount >= 26)
        {
            colCount = colCount - 26;
            rev++;
        }

        returnCharCount += CharacterIncrement(rev-1);
        returnCharCount += CharacterIncrement(colCount);
        return returnCharCount;
    }
}

//--------this loop call this function---------//
int i = 0;
while (i <>
    {
        string CharCount = string.Empty;
        CharCount = CharacterIncrement(i);

        i++;
    }

Beery

fixed formatting, but code seems to be incomplete (take a look at the if and while statements) – Peeved

Woah, recursion for something that simple? You can do that with a simple While, and dividing by 26. – Chrisom

Answer 13

4 ways get English alphabet in Console:

public void ShowEnglishAlphabet()
{
    var firstLetter = 'a';
    var endLetter = 'z';
    for (var letter = firstLetter; letter <= endLetter; letter++)
    {
        Console.WriteLine($"{letter}-{letter.ToString().ToUpper()}");
    }
}

public void ShowEnglishAlphabetFromUnicodeTableDecNumber()
{
    var firstLetter = 97;
    var endLetter = 122;
    for (var letterNumberUnicodeTable = firstLetter; 
    letterNumberUnicodeTable <= endLetter; letterNumberUnicodeTable++)
    {
        Console.WriteLine($"{(char)letterNumberUnicodeTable}- 
        {((char)letterNumberUnicodeTable).ToString().ToUpper()}");
    }
}

public void ShowEnglishAlphabetUnicodeTableEscapeSequence()
{
    var firstLetter = '\u0061';
    var endLetter = '\u007A';
    for (var letterNumberUnicodeTable = firstLetter; 
    letterNumberUnicodeTable <= endLetter; letterNumberUnicodeTable++)
    {
        Console.WriteLine($"{letterNumberUnicodeTable}- 
        {letterNumberUnicodeTable.ToString().ToUpper()}");
    }
}   

public void ShowEnglishAlphabetUnicodeTableLinq()
{
    var alphabets = Enumerable.Range('a', 26).Select(letter => 
    ((char)letter).ToString()).ToList();
    foreach (var letter in alphabets)
    {
        Console.WriteLine($"{letter}-{letter.ToUpper()}");
    }
}

Smallclothes

Even if this is a solution, please provide more information about it and what it does. – Welker

Answer 14

Unfortunately there is no ready-to-use way.

You can use; char[] characters = "ABCDEFGHIJKLMNOPQRSTUVWXYZ".ToCharArray();

Autotomize