Why isn't a line showing on my graph?

I tried graphing using plot(x, y, '-r') and it just put out a blank sheet. Is there something else I have to use to actually graph something?

[Geoff Hayes]

Bella - no, there is nothing else that you need to do to plot your graph. What can you tell us about x and y. Are these scalars or arrays? Try plotting

 plot(x,y,'ro')

instead as that will put a red circle at your coordinates and so will be easier to see.

[Star Strider]

See also: How do you get "plot" to graph a line?

Answer 1

[Walter Roberson]

Typically when that happens the person has the plot(x,y,'-r') in a loop with x and y being scalars. plot() will only create lines between the plots that are present in the same plot() call. The solution in such cases is to store the x and y values in a vector and do the plot after the loop.

   for K = 1 : number_of_iterations
      ...
      x_vector(K) = x;
      y_vector(K) = y;
   end

plot(x_vector, y_vector, '-r')