# Indexing multiple values of an array of structures with a field that varies in length

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John Petersen on 26 Nov 2014
Answered: Geoff Hayes on 26 Nov 2014
I have an array of structures, A. Each structure has a field 'vec'. Each 'vec' is a vector, but the length of the vector can vary with the index into A. So
length( A(i).vec ) = n
length( A(j).vec ) = m
I want to grab the last number of each of these vectors and place them in an array. The idea is something like
x = A(:).vec(end);
but of course that doesn't work.

Geoff Hayes on 26 Nov 2014
John - why not use arrayfun to grab the last element of each structure in your array A. Something like
lastElements = arrayfun(@(x)x.vec(end),A);
This seems to work for the following example
% randomly choose the lengths of 100 vectors
vecLengths = randi(42,100,1);
% create A
A = [];
for k=1:length(vecLengths)
A(k).vec = randi(255,1,vecLengths(k));
end
% get the last element from each vector
lastElements = arrayfun(@(x)x.vec(end),A);

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