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How to reorder legend entries with plot children

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Enoch23
Enoch23 on 29 Oct 2019
Answered: Kris Govertsen on 15 Jan 2021
Hello,
I have a loop creating some plots and on some of them I would like to change the order of the legend entries. I came across a method on StackOverflow, however, it doens't seem to work.
I tried the example in excaza 's answer without success.
When I type in lh.PlotChildren(neworder) I get
>> lh.PlotChildren(neworder)
ans =
4×1 Line array:
Line (y = 3*x)
Line (y = x)
Line (y = x.^2)
Line (y = 2*x)
which is the correct order. However, when assigning
>> lh.PlotChildren = lh.PlotChildren(neworder)
lh =
Legend (y = x, y = 2*x, y = 3*x, y = x.^2) with properties:
String: {'y = x' 'y = 2*x' 'y = 3*x' 'y = x.^2'}
Location: 'northeast'
Orientation: 'vertical'
FontSize: 9
Position: [0.7274 0.7282 0.1589 0.1726]
Units: 'normalized'
Show all properties
it doesn't work. Everything stays as is.
Am I missing something?
  1 Comment
Kyle Marquis
Kyle Marquis on 19 Sep 2020
Also having the same problems, and the solution given by Sebastian Bomberg is not helpful. Did it work for you?Anyone else have a solution?

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Answers (3)

Sebastian Bomberg
Sebastian Bomberg on 29 Oct 2019
You can reorder the children of the axes:
ax = gca;
ax.Children = ax.Children(neworder);
  1 Comment
Kyle Marquis
Kyle Marquis on 19 Sep 2020
I am having the same issues as Enoch23, and your "solution" has not helped. Are you able to show how this re-orders the legend as asked in the question?

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Kyle Marquis
Kyle Marquis on 19 Sep 2020
Edited: Kyle Marquis on 19 Sep 2020
I found a solution that can be used to re-order legend entries without messing up the order in which they are plotted on top of each other (But it doesn't involve plot children). I found it from https://matplotlib.org/1.3.1/users/legend_guide.html , and it's really simple, all you need to do is call
legend([p2, p1], ["line 2", "line 1"])
with p1 being the line object created when you plot
p1 = plot(...)
and together with uistack, I am able to change which objects get plotted on top of which, but then reorder the legend so it makes sense. Example
uistack(psave_d,'top') % Brings certain line to front
legend([psave_a, psave_b, psave_g, psave_c, psave_d, psave_e, psave_f, psave_pde], ["k_y=0.000001 W/m/K","k_y=0.0001 W/m/K","k_y=0.001 W/m/K","k_y=0.01 W/m/K","k_y=0.1 W/m/K","k_y=1 W/m/K","k_y=10 W/m/K","Isothermal PDE Numerical Model"])
If anyone needs more detail, I can gladly provide it. Cheers

Kris Govertsen
Kris Govertsen on 15 Jan 2021
This is how I was able to change the order of the legend on a figure with multiple subplots of area plots:
Before:
I want the order of the legend to follow the order of the colors in the area plot
% a is my figure
% If I type
If I type the following into the command window: a.Children... it returns:
% a.Children
%
% ans =
%
% 5×1 graphics array:
%
% Legend (Grid, VRFB error, VRFB Power, VRFB Energy, LIB error, LIB Power, LIB Energy, Solar, Tidal)
% Axes (Tidal RES)
% Axes (Solar PV RES)
% Axes (VRFB Cost)
% Axes (LIB Cost)
So a.Children(1) is my legend!
% Re-order Legend
lbl = a.Children(1).String; % Retrieve legend labels
numlbl = length(lbl); % Determine number of lables
order = sort(1:1:numlbl,'descend'); % Create array of label numbers in descending order
newlbl = lbl(order); % Create new labels in descending order
legend(findobj(a.Children(2),'Type','area'),newlbl) % Set the legend to follow the new labels
hope this helps!

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