How to change the order of the legend in the Matlab version 2019b?

Hi

I am trying to change the order of legends based upon the user needs. Below is the reference figure and codes (for eg.)

plot([1 2],[15,30])
>> hold on;plot([1 2],[5,35]);
>> hold on;plot([1 2],[40 40],'--k');

How to change the order of legend in the attached figure?

Answer 1

[Dave B]

With your existing .fig file, grab the line objects and feed them into legend in whatever order you like:

open('check.fig')
kids=findobj(gca,'type','Line');
legend(kids)  

% or legend(kids([2 3 1])) if that's the order you like
% or legend(kids,'abc','def','ghi') if you want to update the labels

For a new plot:

figure

h1=plot([1 2],[15,30],'r','LineWidth',2);
hold on;
h2=plot([1 2],[5,35],'b','LineWidth',2);
h3=plot([1 2],[40 40],'--k','LineWidth',2);
ylim([5 50])
legend([h3 h2 h1],'3','2','1')

[Gopinath Karuppannan]

Thanks for the response.

My focus is editing the existing plots rather than for a new plot.

May i know the order of plot which we are giving is based upon the order of legend, Am i correct?

So,

Order - [1 2 3] ==> A B C

Order - [2 3 1] ==> B C A

Like above the order of legend has to be replaced right? But it doesn't behave as i mentioned.

The below figure is given in the order of [2 3 1]. I expected as [ B C A] but what i get is different.

I hope you have understand the issue. Can you explain if my understanding on the legend order is wrong.

Thanks

[Gopinath Karuppannan]

Hi

FYI: I have checked with different scenario in the order. Only two of them getting as in correct order.

Order - [1 2 3] ==> A B C

Order - [3 2 1] ==> C B A

Other than that, I am getting wrong. Refer the following image.

Thanks in advance.

[Dave B]

You're generally correct in your understanding but everything is upside down from what you described. That's a little confusing. I'd be surprised if that changed since 2019b, so I'm a little puzzled by your graphic above. In any case, you can be unambiguous about it by looking directly at the kids vector (see below) and you can certainly plot every combination (also below).

In general, I expect the first element of the kids vector that I defined above is the last thing plotted, and the last element of the kids vector is the first element plotted.

open('check.fig');
% I'm removing the semicolon so we can see what's in kids
% If you wanted to check these values programatically, you could use
% get(kids,'DisplayName') to get their 'names' or you can get some 
% other aspect of them that you'd like to use to guide their order
kids=findobj(gca,'type','Line') 

kids = 
  3×1 Line array:

  Line    (C)
  Line    (B)
  Line    (A)

orig=gca;

Here's a look at all the combinations of orders:

figure;
t = tiledlayout(2,3);
p=perms([1 2 3]);
for i = 1:height(p)
    h=copyobj(orig,t);
    h.Layout.Tile=i;
    kids=findobj(h,'type','Line');
    legend(h,kids(p(i,:)));
    title(h,sprintf('[%d %d %d]',p(i,:)))
end

[Gopinath Karuppannan]

Okay Perfect. Thanks for the explanation. I understood it clearly. i can do further on this one.