How to create one plot with multiple lines in a for loop?

Hello,

I have been trying to create a plot, with an unknown number of lines. Each should be on the same graph, and a different colour. However, I am only getting one line on my graph.

This is my code currently:

y = cell(numFiles,1) ;
x = [30:10:100]
figure(); 
hold on
for k = 1:numFiles
    %Code that generates data
    y{k} = [h g f e d c b a ]
    plot(x,y{k}, 'Color', [rand,rand,rand])
end
 
title('SNR / Index')
hold off 

What am I doing wrong? Thank you!

Answer 1

[Jan]

x = 30:10:100;
figure();
% axes('NextPlot', 'add');  % Same as: hold on
hold on
for k = 1:8
    y{k} = rand(size(x));
    plot(x, y{k}, 'Color', rand(1, 3))
end

You see, it works with hold('on') or with creating the axes explicitly also.

Are you sure, that this is your code and there is no cla anywhere?

[AK]

It still isn’t working using hold on or axes().

All the code is mine. I just don’t really understand why only one line shows, as from my limited knowledge, it should.

[Jan]

But you see, that my code, which only replaces your "y{k} = [h g f e d c b a ]" by some random data, does show a set of lines. So the difference must be inside, what is hidden in "y{k} = [h g f e d c b a ]". Show us this important part.

[Jan]

As assume, your code contains a command, which clear the axes: imshow(i) command in generating_prob() .

You can find such problems by using the debugger: Set a breakpoint in the code and step through the functions line by line. Then you will see, which command has the observed effekt.

[AK]

Thank you! This worked! I need to use the debugger more often.

[Jan]

The debugger is the best friend of the programmer.