averaging

I have a matrix composed of 12 columns representing depths from 1 to 12 and I have thousands of rows which represent 2 minute intervals at which the measurements were taken. how could I change the values to show hourly averages? As in average every 30 rows! I've tried using reshape to do this but cant get my head around it.

thanks

Answer 1

[Andrei Bobrov]

d=randi(127,90,12);
out = squeeze(mean(reshape(d.',size(d,2),30,[]),2)).';

or

n = 30;
a = zeros(size(d)./[n 1]);
k1 = (n-1:-1:0);
for j1 = 1:size(d,1)/n
    k = j1*n - k1;
    a(j1,:) = mean(d(k,:));
end

or 2

out2 = blockproc(d,[30, size(d,2)],@(block_struct)mean(block_struct.data))

Answer 2

[Fangjun Jiang]

d=rand(90,12);
[M,N]=size(d);
e=mat2cell(d,30*ones(M/30,1),N);
f=cellfun(@mean,e,'uni',false);
g=cell2mat(f);

Answer 3

[ricco]

both work perfect, thanks.