flatten a struct of arbitrarily nested arrays of integers into a flat array of integers

Question

Is it possible to flatten an array of arbitrarily nested arrays of integers into a flat array of integers in Matlab? For example,

[[1,2,[3]],4] -> [1,2,3         


        

Answer 1

I think you will have to adapt the flatten function from the file exchange to use struct2cell so something like this:

function C = flatten_struct(A)

    A = struct2cell(A);
    C = [];
    for i=1:numel(A)  
        if(isstruct(A{i}))
            C = [C,flatten_struct(A{i})];
        else
            C = [C,A{i}]; 
        end
    end

end

This results in:

a.c = [5,4];
a.b.a=[9];
a.b.d=[1,2];

flatten_struct(a)

ans =

    5    4    9    1    2

So the order is in the order you declared your struct instead of in your example order which I presume is alphabetical. But you have control over this so it shouldn't be a problem.