convert an array of numbers into letters; 1 =a, 2 =b, 3 = c etc.

So i have created a function that returns a row vector of numbers, Example:

[3, 6, 12, 1, 1, 3].

I want to write a new function that turns these numbers into letters. And in a form that i can call call it for any size set of results using a rule such as

1 = A, 2 = B, 3 = C, 4 = D, etc.

I see there is a num2str function but i dont really understand how to implement this as a function that will perform the conversion on each element in the vector.

What would be the best way to do this?

Answer 1

[Matt Kindig]

Alphabet = 'ABCDEFGHIJKLMNOPQRSTUVWXYZ'

numbers = [3,6,12,1,1,3]
letters = Alphabet(numbers)

Or using the ASCII codes:

letters = char(numbers + 64);

[David Mehr]

Thank you Matt for your swift response,

this is great (Y)

one quick question: is it possible to denote a character in your alphabet by more than one symbol?

E.G A a2 B b2 C c2 -

thank you :)

[kclamb]

Alphabet = {'ABCDEFGHIJKLMNOPQRSTUVWXYZ','abcdefghijklmnopqrstuvwxyz'}
numbers = [3,6,12,1,1,3]
letters = Alphabet{1}(numbers)
letters = Alphabet{2}(numbers)

[Walter Roberson]

Substitutions = {'Alpha', 'Bob', 'Charlie', 'Delta'};
mapped = Substitutions(numbers);
strjoin(mapped, {' '})     %if you want them blank separated in one string

[Ivan Mich]

If someone wants to do the opposite? That is, based on the letters to find the numbers that were set (I mean if I have the word HELLO, which numbers correspont to the above letters?)

[Image Analyst]

@Ivan Mich, give a specific example of what you're starting with (data plus the look up table), and your desired/expected output.

[Walter Roberson]

@Ivan Mich

Alphabet = 'ABCDEF'

Alphabet = 'ABCDEF'

numbers = [3,6,12,1,1,3];
map(Alphabet) = numbers;

map('DEADBEAF')

ans = 1×8

1 1 3 1 6 1 3 3

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Answer 2

[Image Analyst]

Try this:

asciiValues = [3, 6, 12, 1, 1, 3]
asciiChars = char(asciiValues+'A'-1)

In the command window:

asciiValues =
     3     6    12     1     1     3
asciiChars =
CFLAAC

[Image Analyst]

For lower case you can either do lower(asciiChars), or do this:

asciiChars = char(asciiValues+'a'-1)

[David Mehr]

thank you

Answer 3

[Jay]

You can create a simple MATLAB function to convert numbers to letters like this:

function letterStr = num2letterVec(numVec)
    % Convert each number in the vector to a letter (1=A, 2=B, ..., 26=Z)
    letters = 'ABCDEFGHIJKLMNOPQRSTUVWXYZ';
    % Use modulo 26 to handle numbers > 26
    letterStr = letters(mod(numVec-1, 26)+1);
end

This function works for any size vector, and numbers greater than 26 will wrap around automatically.

If you want to explore similar number-to-letter conversions online, you can check numberstoletters.com for inspiration and alternative mappings.

[Walter Roberson]

I would suggest a minor adjustment:

    letterStr = letters(mod(numVec-1, length(letters))+1);

This avoids the "magic number", and makes it easier to adjust if letters changes.

[Jay]

make sense, thank you for updating the code..

function letterStr = num2letterVec(numVec)
    %NUM2LETTERVEC Convert a numeric vector to letters (1=A, 2=B, ..., 26=Z)
    %   Handles numbers > 26 by wrapping around using modulo.
    %   Non-integer values are rounded to the nearest integer.

    % Define the letters
    letters = 'ABCDEFGHIJKLMNOPQRSTUVWXYZ';

    % Round numbers to nearest integer
    numVec = round(numVec);

    % Convert numbers to letters using modulo
    letterStr = letters(mod(numVec - 1, length(letters)) + 1);
end