Matlab: Numerical array index into a string array (without loops)

Question

I\'m doing a set of problems from the MATLAB\'s introductory course at MIT OCW. You can see it here, it\'s problem number 9, part g.iii.

I have one matrix with the final

Answer 1

Try:

letters=['F','D','C','B','A'];
tg = [1 2 1 3 3 1];
letters(tg)

Result:

ans = FDFCCF

This works even when tg (total grade) is a matrix:

letters=['F','D','C','B','A'];
tg = [1 2 1 ; 3 3 1];
result = letters(tg);
result


result =                                                                                                                                                                             

FDF                                                                                                                                                                             
CCF

Edit (brief explanation):
It is easy to understand that when you do letters(2) you get the second element of letters (D).

But you can also select several elements from letters by giving it an array: letters([1 2]) will return the first and second elements (FD).

So, letters(indexesArray) will result in a new array that has the same length of indexesArray. But, this array has to contain numbers from 1 to the length of letters (or an error will pop up).