sort boxplot based on 25-75th percentiles

Hi all,

I have a figure with 3 boxplots in it (different colors each of them)

However, I would like to sort them based on the difference between 25th-75th percentile.

Is it possible to do it?

And if yes can I keep the initial colours after they have been sorted?

thanks a lot

NIkolas

Answer 1

[the cyclist]

Yes, it is possible. The algorithm would be something like

• Find the percentiles on the data, using the prctile command, before plotting them with boxplot
• Sort those percentiles, and store the sorting order
• Use a grouping variable (the second argument to the boxplot command), making sure that the grouping variable values are sorted according to the correct order

I could probably give more specific advice if you upload the data and code that you are using now.

[Nikolas Spiliopoulos]

Hi again,

thanks for the answer

here is a simple example, where I have 9 bars in one figure with 3 different colours.

I don't fully unterstand how I sort them

thanks again

A=[rand(50,1) 2*rand(50,1) 3.5 *rand(50,1) 1.8*rand(50,1) 0.7*rand(50,1) 0.5*rand(50,1) 4*rand(50,1) 3.1*rand(50,1) 7*rand(50,1)]; %Random matrix


figure(01)
g=boxplot(A);
set(g(5,1:3), 'Color', 'r');
set(g(5,4:6), 'Color', 'b');
set(g(5,7:9), 'Color', 'g');

[the cyclist]

I think this does what you want. You want the colors of the box plots to be retained from the original, unsorted boxplot, right?

A=[rand(50,1) 2*rand(50,1) 3.5 *rand(50,1) 1.8*rand(50,1) 0.7*rand(50,1) 0.5*rand(50,1) 4*rand(50,1) 3.1*rand(50,1) 7*rand(50,1)]; %Random matrix

p25 = prctile(A,25);
p75 = prctile(A,75);

[~,sortingOrder] = sort(p75-p25);
[~,unsortingOrder] = sort(sortingOrder);

sortedA = A(:,sortingOrder);

figure
g=boxplot(sortedA);
set(g(5,unsortingOrder(1:3)), 'Color', 'r');
set(g(5,unsortingOrder(4:6)), 'Color', 'b');
set(g(5,unsortingOrder(7:9)), 'Color', 'g');

[Nikolas Spiliopoulos]

Thanks a lot,

that's exactly what I need

cheers!!