MATLAB: I have matrix A, how can I add a row in matrix A with others rows of matrix A

addcolumnmatrixrowssum

I have matrix A, how can I add a row in matrix A with others rows of matrix A ?
For example:
a = ones (220,220);
b = a(:,1)+a(:,11)+a(:,21)+     a(:,31)+a(:,41)+a(:,51)+a(:,61)+a(:,71)+a(:,81)+a(:,91);
I would like to obtain sum of row as b. The problem is the matrix I'm working on is thousands, is there a more easy way to do this? a certain function maybe that only needs me to specify the column number. Thank you!

Best Answer

b = sum(a(:,1:10:91),2)
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