Summation of n-th columns of multiple matrix.

I try to summate the 4th colums of this 15 matrices. I use following code:

P{1}=[0 18 0 0];
P{2}=[31 20 0 0];
P{3}=[51 25 0 0];
P{4}=[75 23.9 0 0];
P{5}=[76.2 25 0 1000];
P{6}=[84.7 25 0 1000];
P{7}=[93.2 31 0 1000];
P{8}=[109.2 46.7 0 1000];
P{9}=[127.2 49.7 0 1000];
P{10}=[145.2 31 0 1000];
P{11}=[161.2 25 0 0];
P{12}=[169.7 25 0 0];
P{13}=[178.2 23.9 0 0];
P{14}=[179.2 25 0 0];
P{15}=[188.4 25 0 0];

for k = 1 : 15
    A{k} = P{k}(4)
    y=sum(A{k})
end

Instead of y=6000 matlab show me that y=0. Maybe anyone show me my mistake.

Answer 1

[Bhuvnesh Singh]

To achieve this you can do something like :

y = 0
for k = 1 : 15
    A{k} = P{k}(4)
    y = y + A{k}
end