MATLAB: Hot to store results from for loop in matrix

for loopstoring output in matrix

So,
I'm having trouble storing my results from a for loop in a matrix. I have a 22*9 matrix for which I want to calculate the diffferennce between the columns, for each row. and store it in a new matrix.
I have tried preallocating with zeroes, does not fix the probelm. Something is wring in my code (see below) but I can't seem to figure out what.
What happens is that the output is either (with preallocation) a 22*9 Matrix with only the output of the last calculation in the first and second column of the matrix.
Or, withour preallocation, I get the result as 9 separate vectors, one for each iteration.
very grateful for some input.
Thx!
The code: 
for m=1:9
if m==1
    deltaCI=0;
    deltaEA=0;
    deltaP=0;
    
else
    %calculate difference for  CI, EI, EA, between year (column) m and m-1 for each of the 22 rows. 
    deltaCI=CI(:, m)- CI(:, m-1);
    deltaEI=EI(:, m)- EI(:, m-1);
    deltaEA=EA(:, m)- EA(:, m-1);
    deltaP=P(:, m)- P(:, m-1);  
end'
    deltaCI(:,m)=deltaCI
    deltaEI(:,m)=deltaEI
    deltaEA(:,m)=deltaEA
end
resultsco2(:,m)=deltaCI.*deltaEI.*deltaEA.*deltaP;

Best Answer

You need not to run a loop to get the difference..simply use the fucntion diff. 
A = rand(22,9) ; 
A = [zeros(22,1) A] ; 
iwant = diff(A')' ;
Still, if you want o use the loop. Use like this:
deltaCI = zeros(22,9) ; 
deltaEA = zeros(22,9) ; 
deltaP = zeros(22,9) ; 
for m=2:9
    %calculate difference for  CI, EI, EA, between year (column) m and m-1 for each of the 22 rows. 
    deltaCI(:,m)=CI(:, m)- CI(:, m-1);
    deltaEI(:,m)=EI(:, m)- EI(:, m-1);
    deltaEA(:,m)=EA(:, m)- EA(:, m-1);
    deltaP(:,m)=P(:, m)- P(:, m-1);  
end
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