Can MATLAB Handle a Triple Nested Struct?

I am trying to create a Calendar struct where it has Month struct and within the Month struct there is a Day struct. So far I have been able to get the Month struct to work within the Calendar struct :

Calendar = {};
Calendar.year = int8.empty;
Calendar.Month = {};
for i = 1:length(SIData)
    Calendar(i).year = SIData(i).year;        
    Calendar(i).Month(1).month = 'January';
    Calendar(i).Month(2).month = 'February';
    Calendar(i).Month(3).month = 'March';
    Calendar(i).Month(4).month = 'April';
    Calendar(i).Month(5).month = 'May';
    Calendar(i).Month(6).month = 'June';
    Calendar(i).Month(7).month = 'July';
    Calendar(i).Month(8).month = 'August';
    Calendar(i).Month(9).month = 'September';
    Calendar(i).Month(10).month = 'October';
    Calendar(i).Month(11).month = 'November';
    Calendar(i).Month(12).month = 'December';
end

However I cannot get the Day struct to go into the Month struct without throwing an error:

for i = 1:length(Calendar)
    Calendar(i).Month.Day = {};
end

Error Message:

Scalar structure required for this assignment.

Error in Solar_Calc (line 32)
    Calendar(i).Month.Day = {};
    

Any ideas to fix this problem would be greatly appreciated.

Thanks!

[Elliott Tung]

I have also tried to do this:

Calendar.Month.Day = {};

[Stephen23]

"Can MATLAB Handle a Triple Nested Struct?"

Yes.

Your data is very complex. Why are you assigning an empty cell array on one line:

Calendar = {};

and then replacing that and/or assigning lots of individual scalar structures? It appears that there is some confusion about data types: the best way to preallocate a structure is to use the struct command, and avoid

For such simple data your data design is ... complex. You should consider simplifying it.

Answer 1

[Jeff Miller]

Haven't tried it, but it seems like this should work:

for i = 1:length(Calendar)
    for j=1:12
        Calendar(i).Month(j).Day = {};
    end
end

[Elliott Tung]

This works. Thanks!

Answer 2

[Walter Roberson]

 Calendar = struct('Month', repmat({struct('month', '', 'Day', cell(31,1))},12,1), 'year', int8.empty);
 

The result is a 12 x 1 struct with fields Month and year. Each Month is a 31 x 1 struct with fields 'month' and 'Day'.

Might I suggest that this is not the structure that you want? There is no point in repeating month 31 times.