how to concatenate structure fields

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Hello I have a structure s(i).f(j).d where i=1:40 and j=1:10.I want to concantenate all the fields in to one single matrix. for eg
for j=1:10
m(:,j)=s(1).f(j).d
with the following code above
this concatenates 10 column matrix into m .But this is just for s(1) how to proceed for s1..s2...s40 for all the 40 fields?

Accepted Answer

Azzi Abdelmalek
Azzi Abdelmalek on 15 Jul 2016
Look at this example
s(1).f(1).d=11
s(1).f(2).d=12
s(2).f(1).d=21
s(2).f(2).d=22
a=s.f
n=numel(a)
for k=1:numel(s)
M(k,:)=[s(k).f(1:n).d]
end
  4 Comments
Azzi Abdelmalek
Azzi Abdelmalek on 15 Jul 2016
load lbpstructure
a=s.f;
n=numel(a);
M=[]
for k=1:numel(s)
b=[s(k).f(1:n).d];
M=[M;b];
end
M

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More Answers (1)

Guillaume
Guillaume on 15 Jul 2016
Use a double for loop, then:
m = zeros(numel(s(1).f(1).d), numel(s(1).f(1)), numel(s)); %preallocation is advised
for sidx = 1:numel(s)
for fidx = 1:numel(s(sidx).f)
m(:, fidx, sidx) = s(sidx).f(fidx).d;
end
end
Note that I've concatenated the s1, ... s40 along the 3rd dimension. You didn't specify what you wanted exactly.
  2 Comments
Guillaume
Guillaume on 15 Jul 2016
Whichever shape you want for the output, the idea is still the same. Iterate over both arrays. To get the above:
m = zeros(numel(s(1).f(1).d, numel(s) * numel(s(1).f));
col = 1;
for sidx = 1 : numel(s)
for fidx = 1 : numel(f)
m(:, col) = s(sidx).f(idx).d;
col = col + 1;
end
end

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