MATLAB: Index exceeds the number of array elements

Question

Dear all. How can I fix this: "Index exceeds the number of array elements"?

data=[1:30]';
x=data(:,1);
n=length(data);
for i=1:n-2
    for k=1:n-2
          h(k)=sum(data((i):(i+2)));
          k=k+1;
          i=i+3;
    end
end

Thank you all!

Answer 1

One way:

x=(1:30).';
[m,n]=size(x);
N=3;
Result=zeros(m/N,n); % preallocate
for k = 1:m/N
   Result(k,n)=sum(x(k*N-(N-1):k*N));
end
Result

Gives:

Result =
     6
    15
    24
    33
    42
    51
    60
    69
    78
    87