plotting issue along the x-axis !

Hello ! I would like to plot two curves in the same figure, to make my issue more clear let consider the following example:

    x = linspace(0,10,20);
    y = x ;
    y1 = x;
    plot(x,y);hold on
    plot(-x,y1) ;

I would like to get the same general aspect of the figure but with the second curve plotted along [10 0], any suggestions how can I get it done ?! Thank you!

Answer 1

[Star Strider]

Use fliplr (or flip) on the x argument in the second plot call:

x = linspace(0,10,20);
y = x ;
y1 = x;
plot(x,y)
hold on
plot(fliplr(x),y1)
hold off

[Ano]

thank you for your answer but it didn't work , actually I would like to have an x-axis along [0 10] but with two directions as showing in the figure attached

[Star Strider]

The easiest way is to simply re-label the x-axis:

x = linspace(0,10,20);
y = x ;
y1 = x;
plot(x,y)
hold on
plot(-x,y1)
hold off
set(gca, 'XTickLabel', [10:-2:0 2:2:10])

EDIT —

Another option:

x = linspace(0,10,20);
y = x ;
y1 = x;
plot(x,y)
hold on
plot(-x,y1)
hold off
xt = get(gca, 'XTick');
lxt = length(xt);
set(gca, 'XTickLabel', [-(xt(1:fix(lxt/2))) xt(fix(lxt/2)+1:end)])

The second option is robust to the values of ‘xt’.

[Ano]

thank you very much for your reply! the second option outputted the x-axis without any scale. I wanted to know how can I keep the same figure with all the specifications but to plot y1= x and not y1 = -x , any suggestions?

[Star Strider]

I have no idea what you want to do.

Try this:

x = linspace(-10,10,21);
y = abs(x);
plot(x,y)
xt = get(gca, 'XTick');
lxt = length(xt);
set(gca, 'XTickLabel', [-(xt(1:fix(lxt/2))) xt(fix(lxt/2)+1:end)])

[Ano]

thanks it works ! the general idea that I would like to learn how to do is how can I divide my figure (subplot is not what I mean here) so that I will get from the center to the Left plot var1 , and from the center to the right plot var2 , is it clear now to you what I what to do ?!

[Star Strider]

In the code in my previous Comment, I used the same function plotted over the negative and positive axes, and then took the absolute value of it and re-labeled the x-axis.

If you want to plot two different functions on the same axes, you can do what I did here (plot the absolute value of the second function over the negative axis), then re-label the axes.

Plotting the absolute value of the second function and then re-labeling the axes appears to be the result you want.

Example —

x = linspace(-2.1, 10, 51);
y1 = x;
y2 = abs(x).^3;

figure(1)
plot(x(x>=0), y1(x>=0))
hold on
plot(x(x<=0), y2(x<=0))
hold off
xt = get(gca, 'XTick');
lxt = length(xt);
set(gca, 'XTickLabel', [-(xt(1:fix(lxt/2))) xt(fix(lxt/2)+1:end)])

This appears to be reasonably robust.

[Ano]

thank you very much !

[Star Strider]

As always, my pleasure!