Help creating a for loop

I am taking some data in a 28x6 matrix and I am wanting to create a for loop that takes the value in each position in and divides that value by the sum of the entire row and then replace said value with that new calculated value. Then do this for each value in the matrix.

For example if I have the matrix:

[1 2 3 ; 4 5 6]

I would like to create a loop that makes the following matrix from the above matrix:

[(1/(1+2+3)) (2/(1+2+3)) (3/(1+2+3)) ; (4/(4+5+6)) (5/(4+5+6)) (6/(4+5+6))]

I am not sure how to go about this in a for loop and would appreciate the help.

Answer 1

[Walter Roberson]

M = [1 2 3 ; 4 5 6];
M ./ sum(M,2)

Note: this code requires R2016b or later. For earlier versions,

bsxfun(@rdivide, M, sum(M,2))