MATLAB: Calculating annual means for different time periods

Question

Hello,

I am trying to calculate annual means from monthly data for a number of basins with different time periods.

my data looks something like this:

time (year/month)            Amazon       Congo      .....
195101                            6430            4356
195102                            2530            7960
195103                            1820            2060
.....                                   .....               .....
.....                                   .....               .....
.....                                   .....               .....
200610                            16200          NaN
200611                            6540            NaN
200612                            9870            NaN

and so on. In addition I have two variables specifying the start and end years of the records for each basin as they differ from one basin to another:

start         end
195101    200012
195601    199312
197101    200612
.....          .....

So my questions is: how can I tell matlab to calculate the mean of each year (mean 195101-195112 and so on) and also tell it to start and end calculations at a particular year depending on the basin?

Cheers, Anna

Answer 1

variant

corrected [14:14 MDT]

%{
data - your array (double array) in view :
data = [195101                            6430            4356
195102                            2530            7960
195103                            1820            2060
200610                            16200          NaN
200611                            6540            NaN
200612                            9870            NaN]
%}
dy = datevec(num2str(data(:,1)),'yyyymm');
d1 = [dy(:,1), data(:,2:end)];
t = unique(d1(:,1)); 
outdata = [t, nan(numel(t),size(data,2)-1)];
for j1 = 2:size(data,2)
    t2 = ~isnan(d1(:,j1));
    yrs = unique(d1(t2,1));
    i1 = ismember(outdata(:,1),yrs);
    outdata(i1,j1) = cellfun(@mean,mat2cell(data(t2,j1),histc(d1(t2,1),yrs),1));
end