How to run checks on all rows of structure?

I want to check all the rows in the field of a structure and find out which rows are not empty. Can I get an index without using a loop?

For example, with the following structure:

s.a=rand(5);
s(2,1).a=[];
s(3,1).a=rand(5);
s(4,1).a=[];

I would be hoping for something like:

idx=[1 0 1 0].';

My current code is:

idx = zeros(size(s,1),1);
for c = 1:size(s,1)
    if ~isempty(s(c).a)
        idx(c)=1;
    end
end

EDIT: subscripts for structure with rows as opposed to columns.

Answer 1

[Stephen23]

"How to run checks on all rows of structure?"

Your structure only has one row (and four columns):

>> size(s)
ans =
   1   4

If you want to check the size of a particular field of a non-scalar structure, then try something like this:

>> F = @(q)isempty(q.a);
>> X = ~arrayfun(F,s)
X =
  1  0  1  0

[Turlough Hughes]

Thanks. It works on rows as well. The sample I gave above was a mistake.