Assigning letters to numbers

I want to come up with a script for the following...

assign letters to numbers but in reverse (A = 26, B=25, etc).

Then, use that to solve basic problems like

1. Sum of first name + Last name

2. Ratio of first name / Last name

3. Sum of first name raise to power of sum of last name

NAME: Keanu Reeves

** I would show what i have but I really have no idea what im doing. I tried to find examples but im still struggling bad.

[Adam Danz]

What's the end goal here? What problems are you solving? Do capital letters have different values than lowercase letters?

You can convert letters to numbers using double().

double('Mike Keup')
ans =
    77   105   107   101    32    75   101   117   112
    
sum(double('Mike Keup'))    
ans =
   827
   
mean(double('Mike Keup'))
ans =
       91.889

[David Hill]

function [morseText,morseSound] = text2morse(string,playSound)
 
%% Translate AlphaNumeric Text to Morse Text
 
    string = lower(string);
 
    %Defined such that the ascii code of the characters in the string map
    %to the indecies of the dictionary.
    morseDictionary = {{' ',' '},{'',''},{'',''},{'',''},...
                       {'',''},{'',''},{'',''},{'',''},{'',''},{'',''},...
                       {'',''},{'',''},{'',''},{'',''},{'',''},{'',''},...
                       {'0','-----'},{'1','.----'},{'2','..---'},{'3','...--'},...
                       {'4','....-'},{'5','.....'},{'6','-....'},{'7','--...'},...
                       {'8','---..'},{'9','----.'},...
                       {'',''},{'',''},{'',''},{'',''},{'',''},{'',''},...
                       {'',''},{'',''},{'',''},{'',''},{'',''},{'',''},...
                       {'',''},{'',''},{'',''},{'',''},{'',''},{'',''},...
                       {'',''},{'',''},{'',''},{'',''},{'',''},{'',''},...
                       {'',''},{'',''},{'',''},{'',''},{'',''},{'',''},...
                       {'',''},{'',''},{'',''},{'',''},{'',''},{'',''},...
                       {'',''},{'',''},{'',''},...
                       {'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','--..'}};
 
    %Iterates through each letter in the string and converts it to morse
    %code
    morseText = arrayfun(@(x)[morseDictionary{x}{2}],(string - 31),'UniformOutput',false);
 
    %The output of the previous operation is a cell array, we want it to be
    %a string. This line accomplishes that.
    morseText = cell2mat(morseText);

Here is an example that converts text to morse code that might help you.

[Dominic Horne]

What does the 31 represent and why are all of the {'',''} required?

Answer 1

[per isakson]

"assign letters to numbers but in reverse (A = 26, B=25, etc)"

Why not start by making a function that takes letters and returns numbers. letters2numbers would be an appropriate name.

IMO functions makes it easy to divide a task into simpler subtasks. See Functions

An appropriate signature of the function would be

num = letters2numbers( word )

where the input, word, is a sequence of letters, e.g. first name, and num is a vector of numbers. letters2numbers can be implemented in many different ways. I came up with this one

function    num = letters2numbers( word )
    asc = double( upper(word) );    % http://www.asciitable.com/
    num = 26 + double('A') - asc;   % simple arithmetic
end

The Matlab function, double, returns the ascii numbers of the letters in the English alphabet.

>> asc = double( 'ABCZ' )
asc =
    65    66    67    90

and

>> num = 26 + double('A') - asc
num =
    26    25    24     1

converts the ascii-values to the numbers you asked for.

Try the function

>> letters2numbers('A')
ans =
    26
>> letters2numbers('Reeves')
ans =
     9    22    22     5    22     8
>> 

"1. Sum of first name + Last name"

>> sum(letters2numbers('Reeves'))
ans =
    88
    

Now it is possible to put together a function that does the homework

function    out = homework( NAME )
    cac   = strsplit( NAME );
    first = cac{1};
    last  = cac{end};
    out(1) =  sum(letters2numbers(first)) + sum(letters2numbers(last));
    out(2) =  sum(letters2numbers(first)) / sum(letters2numbers(last));
    out(3) =  sum(letters2numbers(first)) ^ sum(letters2numbers(last));
end

and run it

>> out = homework( 'Mike Keup' )
out =
          125       1.2727  3.0227e+101
>> out = homework( 'Keanu Reeves' )
out =
          171      0.94318  7.5661e+168
>> 

If you find the above difficult to follow why not try Matlab Onramp

Two alternate implementations of letters2numbers

function    num = letters2numbers( word )
    len = length( word );
    num = nan( 1, len );
    word = upper( word );
    for jj = 1:len
        num(jj) = strfind( 'ZYXWVUTSRQPONMLKJIHGFEDCBA', word(jj) );
    end
end

The statement

num(jj) = strfind( 'ZYXWVUTSRQPONMLKJIHGFEDCBA', word(jj) );

can be replaced by

num(jj) = find( 'ZYXWVUTSRQPONMLKJIHGFEDCBA' == word(jj) );

And the second alternate implementations

function    num = letters2numbers( word )
    [ ~, num ] = ismember( upper(word), 'ZYXWVUTSRQPONMLKJIHGFEDCBA' );
end

The function homework() doesn't see the differences. The inner is hidden from the calling function.

"I really have no idea what I'm doing" (I assume that you are serious.)