Legend each curve in a single figure from a matlab plot

Question

I want to plot four curves in a single figure from matlab, so I am using hold on. Furthermore, I want to create an legend to each curve, so I wrote the code:

clear all
x=linspace(0,10,100);
x2=linspace(-5,15,100);
x3=linspace(-10,20,100);
x4=linspace(35,40,100);

figure(1)

plot(x,x2)

legend('x2')
hold on 

plot(x,x3)

legend('x3')
hold on

plot(x,x4)

legend('x4')
hold on

plot(x,x)

legend('x')

hold off

But the result is that all my curves are in the same color, and just the last legend "x" has appeared in the figure (see it below).

How can I set one legend to each curve? All curves must have different colors.

pschulz pschulz · Accepted Answer · 2016-12-06T06:21:06

This depends a bit on your matlab version. In older versions (and in octave), plots added through the use of hold on get the same color. In R2015b (i don't know when this was introduced), the individual plots get different colors, but still only one legend is displayed.

To get multiple colors and multiple legend entries, you can specify all data to be plotted in one call, the same for the legends:

plot(x, x, x, x2, x, x3, x, x4);

or

plot(x, [x', x2', x3', x4']);

For the legends, approach the same way:

legend('x', 'x2', 'x3', 'x4');

Legend each curve in a single figure from a matlab plot

2 Answers