Fixing loop values while plotting

Hello All,

I have been practicing matlab for fun for sometime now and I am getting into plotting data structures at the moment. I have been trying to "fix" certain loop values while plotting but I have been having a hard time getting this to work. In the code below, I would like to plot all the 'b" values for y=1 and z=1 while x=1:3. I can easily do this by fixing one of the variables but I currently can not fix y and z at the same time. Please see my simple code below. Any advice would be greatly appreciated! Thank you!

vals.y=[];
vals.x=[];
vals.b=[];
vals.z=[];

for z = 1:3;
for y = 1:3;
   for x=1:3;
       b = x*y*z;
       
vals.y(end+1)=y;
vals.x(end+1)=x;
vals.b(end+1)=b;  
vals.z(end+1)=z;

   end
end
end

plot(vals.b(vals.y==1),vals.x(vals.y==1));
%plot(vals.b(vals.y==1 & vals.z==1,vals.x(vals.y==1 & vals.z==1)); - Would Like to this
% to this

Answer 1

[Shunichi Kusano]

Your code almost works. You need a closing parenthesis.

plot(vals.b(vals.y==1 & vals.z==1,vals.x(vals.y==1 & vals.z==1)) % your code
plot(vals.b(vals.y==1 & vals.z==1),vals.x(vals.y==1 & vals.z==1)) % corrected code

And one suggestion. It's a good practice that you do not use for-loop, if you can. In this case, The following code is prefarable. This is easier to write and faster to calculate.

[vals.x, vals.y, vals.z] = meshgrid(1:3);
b = vals.x .* vals.y .* vals.z;

[Fabiano Da Mota]

Hello Shunichi,

Thank you very much! I have been trying different things for a couple of hours and the solution was simpler than I expected. Thank you again.