How do I make input/output in a function a vector?

I'm trying to make a grade-rounding function. How do I make sure my function works on each value I type in at once. E.g. the inputvector [7.2,10.3] should give me the outputvector [7,10]

function gradesRounded = roundGrade(grades)

if grades <= -2
    gradesRounded=-3;
elseif grades <1 && grades > -2
    gradesRounded=00;

elseif grades < 3 && grades >=1
    gradesRounded=02;

elseif grades < 5.5 && grades >= 3
    gradesRounded=4;

elseif grades < 8.5 && grades > 5.5
    gradesRounded=7;

elseif grades >= 8.5 && grades < 11
    gradesRounded=10;

elseif grades >= 11
    gradesRounded=12;

end
end

Answer 1

[JESUS DAVID ARIZA ROYETH]

one cycle is missing

function gradesRounded = roundGrade(grades)
gradesRounded=grades;
for k=1:numel(grades)
if grades(k) <= -2
    gradesRounded(k)=-3;
elseif grades(k) <1 && grades(k) > -2
    gradesRounded(k)=00;
elseif grades(k) < 3 && grades(k) >=1
    gradesRounded(k)=02;
elseif grades(k) < 5.5 && grades(k) >= 3
    gradesRounded(k)=4;
elseif grades(k) < 8.5 && grades(k) > 5.5
    gradesRounded(k)=7;
elseif grades(k) >= 8.5 && grades(k) < 11
    gradesRounded(k)=10;
elseif grades(k) >= 11
    gradesRounded(k)=12;
end
end
end

[Clara Kühnel]

I made the for loop, but I still get the error message " too many input arguments"

[Ameer Hamza]

Are you calling the function as

roundGrade([7.2,10.3])

or

roundGrade(7.2, 10.3)

[Clara Kühnel]

Ahh, I called it by the second one - I see my mistake. Thank you very much!

[Guillaume]

Now try with

roundGrade([5.5 5.5 5.5])

See discussion in my answer for what is going wrong.

Answer 2

[Guillaume]

You could wrap your existing near endless list of if ... elseif into a for loop... (see answer by Jesus) ...

Or you could use matlab the way it's meant, with the discretize function.

function gradesRounded = roundGrade(grades)
   edge_grade_pair= [-Inf -3; -2 0; 1 2; 3 4; 5.5 7; 8.5 10; 11 12; Inf NaN];
   gradesRounded = edge_grade_pair(discretize(grades, edge_grade_pair(:, 1)), 2);
end

A lot more compact! And it's trivial to add more edges if needed. Just two more values in the matrix.

One minor difference is that the above results in 0 for exact -2 while your code results in -3 but considering that your code is not consistent with which edge is included in which bracket (for example your code won't return anything for exact 5.5 since it's not included in any bracket), I assume you've got it wrong.