Question

I am new to MATLAB so I don’t even know if this is possible, but here it is…
I am trying to print multiple lines in a single graph using the plot function. The problem is, I want to be able to specify how many lines the graph should display by simply changing a variable, for example: {This is the pseudo code to what I want to do}

 number_of_lines = 4;
 x = 0:0.5:5;

 function_output[number_of_lines];

 for n=0:number_of_lines
     function_output[n] = sin(n + x);
 end

 for n=0:number_of_lines
     plot(x,function_output[n]);
 end

I know the above pseudo code isn’t exactly MATLAB, but all I want to know if such algorithm is possible to do in MATLAB.

Answer 1

Here’s one way to implement your example in MATLAB:

function_output = zeros(numel(x), number_of_lines);  % Initialize a 2-D array
for n = 1:number_of_lines                   % MATLAB uses 1-based indexing
    function_output(:, n) = sin(n + x).';  %' Compute a row vector, transpose
                                            %   it into a column vector, and
                                            %   place the data in a column of
                                            %   the 2-D array
end
plot(x, function_output);  % This will plot one line per column of the array

And here are some documentation links you should read through to learn and understand the above code:

• Matrices and Arrays
• Matrix Indexing
• Arithmetic Operators
• The plot function