How to sum average annual data

Let's say I have a code from date 1/1/2004 to 31/12/2018, and I have a data of 5479x1 for each day. How do I sum the data up for each year to obtain an annual data value for each year?

= datetime(2004,01,01):calmonths(1):datetime(2018,12,31);

Answer 1

[KSSV]

Convert your date time into d,m,y, using datevec. Pick a year you want, get it's indices and use mean. Let A be your data.

[y,m,d] = datevec(yourdates) ; 
[c,ia,ib] = unique(y) ;   % get unique years present 
N = length(c) ;   % Total number of years present 
% loopfor each year 
for i = 1:N
    iwant(i) = mean(A(y==i)) ; % get mean of particular year 
end

[Pei Qing Chan]

Thank you!

[KSSV]

Thanks is accepting the answer.. :)