Calling variables instead of values

I had previously asked this: http://www.mathworks.com/matlabcentral/answers/19875-calling-variables-instead-of-values And marked as answered, but I have a little hiccup.

I have this:

    A=6; B=7; C=5;
    x = [7 5 6]

I want to call x1 as:

x1 = 
    B     C     A

Previous answered:

    x = [2 3 1]
    xc = {'A' 'B' 'C'}
    x1 = xc(x)

This line of code only works for values that are within the number of columns of the matrix.

Answer 1

[Alex]

In the previous question you have a single set (x) that has several elements that you want to link to.

In the new problem, you do not have a single set, so you have a way to search each of the possible solutions. There is no easy way to do this. The two ways I know how to do this is with if/else tree (messy), or an enumerator and switch/case setup (not as messy).

if/else tree example

for i = 1:3
    if(x(i) == A)
      x1(i) = 'A';
    elseif( x(i) == B)
    ...
    ...
    end
end

The other option is using enumeration and switch/case. I've only used enumeration in older versions, so the following is a quick setup for 2009 A.

classdeff my_letters (Enumeration) < int32
proerties
 A = 6;
 B = 7;
 C = 8;
end
methods (static)
function str = string(input)
    switch int32(input)
        case my_letter.A
           str = 'A';
...
...
...
    end
end

Now you can use a switch case as opposed to an if-else tree

Switch x(i)
   case int32(my_letters.A) 
        X1(i) = my_letters.A.string();
...
...
end

The switch/Case is cleaner and faster code wise.

[Will]

Thank you very much. I had not done much reading on 1-to-1 and 1-to-many analyses. Very helpful, thank you.

[Andrei Bobrov]

S = {'A' 'B' 'C'}

C =[6 7 5]

x = [7 5 6]

[loc,loc] = ismember(x,C)

out = S(loc)

Answer 2

[Alex]

My original comment about one-to-one, I realize, is not the best descriptor.

I've since edited the original post to reflect that and I'll try to explain the differences a little better.

In your original question, you have a base set (x) and you are looking to match values within that set. Since all the values are contained within a single set, this is easy.

In the new question, there are multiple sets (A, B, & C) that all have to be searched since each one could possibly contain the solution that you desire.

If there is a way to combine the multiple sets (like Will's above comment) into a single set (set S in Will's example), then the solution can be achieved much easier. Otherwise, the if/else tree or the switch/case ideas I mentioned are the best options, that I know of.