MATLAB: Access Data in Nested Structure using For loop - matlab

Question

Good day,
I have a nested structure in this format.
Data: [1x1 struct]
a: [1x1 struct]
a1: [10x1 double]
a2: [10x1 double]
a3: [10x1 double]
b: [1x1 struct]
b1: [10x1 double]
b2: [10x1 double]
c: [1x1 struct]
c1: [10x1 double]
c2: [10x1 double]
c3: [10x1 double]
c4: [10x1 double]
Each of sub-fields of a, b & c are duration percentage of an event in buckets. The number of elements in each bucket are number of data-sets. I'd like sum the bucket values of each data set and discard the entire data-set if they don't add up to 100%. How may I access each element of the buckets for a, b & c fields of Data using for loop in a simply format.
EDIT: I figured out how to call the sub-fields & it's elements, sum the percentages & now, if the data-sets not adding up to 100 need to fully removed from each sub-field.
field = fieldnames(Data);
for group = 1:length(field)
for subfield = fieldnames(Data.(field{group}))
fieldSize = structfun(#(field) length(field),Data.(field{group}));
nb_datasets = fieldSize(1,1);
for jj = 1:nb_datasets
for ii = 1:length(subfield)
a_dataset_pcts(jj,ii) = Data.(field{group}).(subfield{ii})(jj,1);
end
a_pct_total(jj,:) = sum(a_dataset_pcts(jj,:));
end
end
end

Answer 1

Matlab like matrices Bensa.... You should drop your approach now.
Fixed size datasets
If all a, b, c arrays are 10x1 sized, you should switch immediately to a cell of arrays, being the index the durations, and the arrays columns the datasets for each duration:
a: [1x1 cell]
a{1}: [10xna double]
a{2}: [10xnb double]
a{3}: [10xnc double]
All statistics go easy. You have two for loops, one for the durations, other for the dataset. Matlab vectorizes the functions inside each dataset (most of the time). In here, i am assuming max(.) is your aggregation array function for obtaining statistics:
n=length(a);
for i=1:n
ni=size(a{i},2);
for j=1:ni
max(a{i})
mean(a{i}')'
if j==j0 && i==i0
a{i}(:,j)=[]; % Cleanup j0th event in i0th dataset
end
end
end
Do you need to compare a.a1 & b.b1 & c.c1? If that is true, then you forcedly should create the auxiliar array x, and then get your stats:
for i=1:n
x(:,i)=a{i};
end
max(x')'
Variable size datasets
If the a, b, c arrays are different each time, then you upgrade the last data and switch to a cell of cells:
a{1}: [1xna cell]
a{1,1}: [la(1)x1 double]
...
a{1,na}: [la(na)x1 double]
a{2}: [1xnb cell]
...
a{3}: [1xnc cell]
...
In here the max(.')' approach is useless, because every dataset could be of different length. If that is the case, you still can reference the data as usually through columns:
n=length(a);
for i=1:n
ni(i)=size(a{i},2);
for j=1:ni(i)
li=length(a{i,j}) % Length of each dataset
max(a{i,j})
% mean(a{i}')' % This do not work anymore
if j==j0 && i==i0
a{i,j}=[]; % Cleanup j0th event in i0th dataset
end
end
end
Do this make sense?. Feel free to comment below...