Create a grouped boxplot

I have 3 groups of data A, B, and C.

A = rand(100,8);
B = rand(100,8)*2;
C = rand(100,8)*4;

I want to plot Box chart of grpup A,B and C.

The internal label of each group is {'a' 'b' 'c' 'd' 'e' 'f' 'g' 'h'}.

I found boxplotgroup(), and used below code

data = {A,B,C};
boxplotGroup(data, 'PrimaryLabels', {'a' 'b' 'c' 'd' 'e' 'f' 'g' 'h'}, ...
  'SecondaryLabels',{'A', 'B' 'C'}, 'InterGroupSpace', 3)

But I got this error.

Error using assert (line 5)
The number of primary labels must equal either the number of bars per group
(3) or the number of total bars (24).

Error in boxplotGroup (line 155)
    assert(ismember(numel(p.Results.primarylabels),[nMembers,
    nMembers*nGroups]), ...

Error in (line 13)
boxplotGroup(data, 'PrimaryLabels', {'a' 'b' 'c' 'd' 'e' 'f' 'g' 'h'}, ...
 

Answer 1

[Christopher McCausland]

Hi NA,

From the documentation here (See section boxplotGroup(__,'primaryLabels',c) ) the number of primary lables should match the number of boxplotGroups. i.e. you appear to be plotting three box plots (A,B,C) but trying to give these box plots eight names ('a' 'b' 'c' 'd' 'e' 'f' 'g' 'h').

I beleive that you are trying to show something like the last example in boxplotGroup(__,'secondaryLabels',s) (shown below) in which case swap your primary and secondary labels.

Let me know if that helps,

Christopher

[NA]

Actually, I want this plot. (Suppose the blue bands are box plot)

[Adam Danz]

@Christopher McCausland thanks for providing support.

@NA I know the boxplotGroup inputs are not intuitive. I may try to improve that in the future while maintaining backward compatibility.

If A B and C are all the same size, here's the solution. If they aren't the same size, you need to pad the smaller matrices with NaN values to make the equal.

A = rand(100,8);
B = rand(100,8)*2;
C = rand(100,8)*4;

D = squeeze(mat2cell(permute(cat(3,A,B,C),[1,3,2]),size(A,1),3,ones(1,size(A,2))));
%                                        Number of matricies ^

clf
boxplotGroup(D','PrimaryLabels', {'a' 'b' 'c' 'd' 'e' 'f' 'g' 'h'}, ...
  'SecondaryLabels',{'A', 'B' 'C'}, 'InterGroupSpace', 3)