Using for loop to create monthly data sets from a timetable with annual data

I have a large timetable datafile that include data for an entire year and 7 columns of additional values. I'm trying to extract the data for each individual month and store the entire rows of data for that month in a seperate table or timetable for further processing within the loop.

Currently I'm able to sort the annual data for a single month by using the code

S = timerange('08/01/1985 00:00:00','09/01/1985 00:00:00');
AugustData = TT(S,:);

I considered something like:

n = 12; 
for i = 1:n
    monthStart = [num2str(i) '/01/1985 00:00:00'];
    monthEnd = [num2str(i+1) '/01/1985 00:00:00'];
    S = timerange(monthStart, monthEnd);
    AugustData = TT(S,:);
end 

However, [num2str(i) '/01/1985 00:00:00'] come out as a char rather than a time. Is there a way to pass a dynamic variable into a time range?

I would appreiciate it if anyone know of any ways to get the data for all 12 month without having to repeat the above code 12 times.

[dpb]

"I'm trying to extract the data for each individual month and store the entire rows of data for that month in a seperate table or timetable for further processing within the loop. "

Do NOT do this!!!

Use findgroups and splitapply or varfun or similar techniques instead. Precisely the sort of thing they were made for...

Answer 1

[Peter Perkins]

+1 to what dpb said, but if you really want to do this

timerange(datetime(1985,i,1),datetime(1985,i+1,1))

should do it.

To use findgroups, you may want to temporarily add a variable to the timetable, e.g.

tt.Month = month(tt.Time)