accessing multiple individual struct field values

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I have made a structure like so;
xfr = struct('name',[],'sn',zeros(tmp,1),'xs',zeros(tmp,1),'f',[],'amp',[],'unphas',[],'lincoh',[]);
and filled the fields amp,unphas, and lincoh with 4 double values. xfr is 1x15. I need to make a scatter plot of one field vs the first value of unphas [unphas(1)]
I can easily extract all of the xs values: xfr.xs
How can I extract the first (or second, third, or fourth) value of unphas for all xfr ?
I have tried many different ways without success
a = [xfr(1:15).unphas(4)]
Expected one output from a curly brace or dot indexing
expression, but there were 15 results.

Answers (1)

Stephen23
Stephen23 on 20 May 2021
Edited: Stephen23 on 20 May 2021
S(1).data = [1;2;3];
S(2).data = [4;5;6];
S(3).data = [7;8;9];
n = 2;
V = arrayfun(@(s)s.data(n),S)
V = 1×3
2 5 8
or (assuming that each field contains a column vector):
M = [S.data];
V = M(2,:)
V = 1×3
2 5 8
  2 Comments
Darren Reed
Darren Reed on 20 May 2021
I don't think I have column vectors in the structure xfr.unphas
The data is put into the structure within a double loop as this:
xfr(i).unphas(j) = unphas(mxi+ids(j,1));
Is there any other way to put the data into the xfr.unphas field to make it a column vector?
Thanks
Stephen23
Stephen23 on 21 May 2021
The arrayfun approach does not assume anything about the orientation or size of the array. Try that first.

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