This is a limitation of the struct( ) function when fed a cell array. If you examine s you will see it is not what you wanted.
You could do it in two steps
>> s = struct(field1,value1,field2,[],field3,value3,field4,value4);
>> s.(field2) = value2
s =
struct with fields:
f1: [1 2]
f2: {[1] [2] [32] 'text'}
f3: [3.1416 9.8696]
f4: [1 2 3]
>> cellfun(@(u) numel(u), value2)
ans =
1 1 1 4
>> cellfun(@(u) numel(u), s.f2)
ans =
1 1 1 4
The last one should throw an error because s is not a cell array
>> cellfun(@(u) numel(u.f2), s)
Error using cellfun
Input #2 expected to be a cell array, was struct instead.
