Indexing/Accessing MATLAB nested structure

Question

Hope, that I'm not creating a duplicate, but so far I didn't find the right answer for my problem.

Let's say, we have the following structure(s):

a(1).b = 1;
a(1).x.y = 2;

a(2).b = 3;
a(2).x.y = 4;

When I now try to get all values of b, I can do:

>> a(:).b

ans = 1
ans = 3

But how to this with the nested struct .x.y?

>> a(:).x.y

Expected one output from a curly brace or dot indexing expression, but there were 2 results.

Thanks for your help...!

Interesting to know that Octave support multiple consecutive indexing, so with octave you can use `[[a.x].y]` or `[a.x].y`. — obchardon, Mar 27 '19 at 09:31
Also if someone know why this has not be implemented in matlab: I'm interested. — obchardon, Mar 27 '19 at 09:34

Sardar Usama · Accepted Answer · 2019-03-27T09:16:56.057

5

Just loop over the indices.

>> arrayfun(@(k) a(k).x.y, 1:numel(a))

ans =

     2     4

or:

>> struct2array(cell2mat(extractfield(a,'x')))

ans =

     2     4

edited Mar 27 '19 at 09:16

answered Mar 27 '19 at 08:42

Sardar Usama

Thanks! I was aware of ´arrayfun´ but didn't find the right way how to implement it. – Joojoo Mar 28 '19 at 09:16

1 Answers1