Sorting a matrix with conditions to a new vector column

If I have a matrix

A = [2 5 6 0 4 9 10 3 2 7 5];

and I'd like to sort it in a for loop with a condition such that, for example, 9 or above gets an A, 7 or below gets a B, 5 or below gets a C, and 3 or below gets an F. How can I write a for loop that would give me a column vector with the classifications (A, B, C...)?

I've tried writing a loop with an index set to the length of A, but I'm not sure what to do about it.

Any help is appreciated

[Ameer Hamza]

Can you show an example of output? What do you expect the values of A, B, C, ... after running the code.

Answer 1

[Ameer Hamza]

Try this

A = [2 5 6 0 4 9 10 3 2 7 5];

edges = [0 3 5 7 9 inf];
grades = {'F', 'D', 'C', 'B', 'A'};
idx = discretize(A, edges);
B = grades(idx);

[A, idx] = sort(A, 'descend');
B = B(idx);

t = table(A.', B.', 'VariableNames', {'Grades', 'Grade Letter'})

Result

t =
  11×2 table
    Grades    Grade Letter
    ______    ____________
      10         {'A'}    
       9         {'A'}    
       7         {'B'}    
       6         {'C'}    
       5         {'C'}    
       5         {'C'}    
       4         {'D'}    
       3         {'D'}    
       2         {'F'}    
       2         {'F'}    
       0         {'F'}    

[Ameer Hamza]

The easiet way is to define a table. Check the updated code.

[Ameer Hamza]

Can you paste your code here?

[Ameer Hamza]

If sorting is not important, then try this

A = [5 ;
    7 ;
    3 ;
    6.1 ;
    5 ;
    4 ;
    3 ;
    2 ;
    1;
    7];
edges = [0 4 5 6 7 inf];
grades = {'5th', '4th', '3rd', '2nd', '1st'}.';
idx = discretize(A, edges);
B = grades(idx);

t = table(A, B, 'VariableNames', {'Grades', 'Grade Letter'})

Result

t =
  10×2 table
    Grades    Grade Letter
    ______    ____________
       5        {'3rd'}   
       7        {'1st'}   
       3        {'5th'}   
     6.1        {'2nd'}   
       5        {'3rd'}   
       4        {'4th'}   
       3        {'5th'}   
       2        {'5th'}   
       1        {'5th'}   
       7        {'1st'}   

[Ameer Hamza]

The vector

edges = [0 4 5 6 7 inf];

have 5 intervals. Therefore the vector grades must also have 5 values. If you want to change the number of elements in grades, then you should also change edges accordingly.