If I understand the problem correctly, you're getting a dataset with variables r0, r1, foo, potato, etc, each one of which contains a struct, and you want to extract the eigVal field from each variable. But the problem is that you can't find a way to loop over the variable names programmatically.
Assuming that's the issue...
Firstly, if you can use 13b or later, you can use tables rather than datasets, which are a bit nicer and allow either named or numeric indexing with {}:
for i = 1:n
arcoeff(i) = mles{:,i}.eigVec;
end
But, either way, you can use dynamic variable referencing in the same way you can with structs:
x = dataset(rand(5,1),rand(5,1))
y = 'Var2'
z = x.(y) % Equivalent to z = x.Var2
So now
vnames = mles.Properties.VarNames;
for i = 1:n
arcoeff(i) = mles.(vnames{i}).eigVec;
end
[Side note: given that the eigenvectors are, well, vectors, I think your indexing will have to be something like arcoeff(:,i) = ...]
[Second side note: the condition if 0.05 - coeff && 0.05 - coeff > 0 isn't well formed: the first part 0.05 - coeff is numeric, so will be converted to logical, which will make it equivalent to 0.05 - coeff > 0 (so you're testing the same thing twice -- "if X && X").]
