MATLAB letter grade from Excel file

I am trying convert the percentage grade I calulcated into letter grades and I do not know how to?

%a) Read the student's information into MATLAB using buil-in function
%readmatirx
data = readmatrix("ITEC2600_Sample_Grades.xls");
%b Create an anoymous fucntion to calculate the studet's final make
Final_Grade = @(data)max(data(:,2:3),[],2)*0.10 +data(:,4)*0.20+data(:,5)*0.20+data(:,6)*0.50;
Final= Final_Grade(data)
%c) find the letter for each grade level

[Voss]

Your percentage grade calculation is weighting the Project at 0.7 and the Final at 0:

Final_Grade = @(data)max(data(:,2:3),[],2)*0.10 +data(:,4)*0.20+data(:,5)*0.20+data(:,5)*0.50;
%                                                                      ^ Project      ^ Project again

I guess that should be Project at 0.2 and Final at 0.5:

Final_Grade = @(data)max(data(:,2:3),[],2)*0.10 +data(:,4)*0.20+data(:,5)*0.20+data(:,6)*0.50;
%                                                                                     ^ Final is column 6

[Victor]

ok thanks it

Answer 1

[Voss]

You need to define which numeric grades map to which letter grades. For example:

letters = 'F':-1:'A';
letters(letters == 'E') = ''

letters = 'FDCBA'

thresholds = [0, 60:10:100]

thresholds = 1×6

0 60 70 80 90 100

Once you do that you may be able to use discretize as follows:

% read file:
data = readmatrix("ITEC2600_Sample_Grades.xls");
% calculate numeric grades:
Final_Grade = max(data(:,2:3),[],2)*0.10 +data(:,4)*0.20+data(:,5)*0.20+data(:,6)*0.50

Final_Grade = 56×1

74.3910 85.1200 86.6620 61.9830 64.3490 55.5670 71.5370 64.9400 85.3990 91.9400

% discretize numeric grades to indices in thresholds, then index into
% letters with those indices:
Final_Letter_Grades = letters(discretize(Final_Grade,thresholds))

Final_Letter_Grades = 'CBBDDFCDBACFCBCDACBBDDDDBCCDFCDCFCBCBCDCCDCCFCDDCCBFCCCD'

[Victor]

I am new at this, but like is there a way to do this using switch or if statements?

[Voss]

Sure.

% if statements:
N = numel(Final_Grade);
Final_Letter_Grades = char(zeros(1,N));
for ii = 1:N
    if Final_Grade(ii) >= 90
        Final_Letter_Grades(ii) = 'A';
    elseif Final_Grade(ii) >= 80
        Final_Letter_Grades(ii) = 'B';
    elseif % etc.
        % ...
    else
        % ...
    end
end

% switch:
N = numel(Final_Grade);
Final_Letter_Grades = char(zeros(1,N));
for ii = 1:N
    switch true
        case Final_Grade(ii) >= 90
            Final_Letter_Grades(ii) = 'A';
        case Final_Grade(ii) >= 80
            Final_Letter_Grades(ii) = 'B';
        case % etc.
            % ...
        otherwise
            % ...
    end
end