Adding Number using for loop

Hi,

I have 2 columns in data, time and s. I want to add all values of S when time = 1. Similarly, I want to repeat this for all values of time. I know this is a simple task, but i am not getting any output . Please help.

Answer 1

[Benjamin Dassé]

Hi,

When time = 1 you can sum all values of S in writing :

sum(S(time==1))

So you can do for all time values

Results = zeros(numel(unique(time)),2)
j=0;
for i = unique(time)'
    j=j+1;
   Results(j,:) = [i sum(Y(time==i))]  % [new_time new_S]
end

Regards,

[Tehreem Syed]

Thanks

Answer 2

[KSSV]

Let A be your n*2 array.

t = A(:,1) ; 
s = A(:,2) ; 
[C,ia,ib] = unique(t) ; 
N = length(C) ; 
iwant = zeros(N,1) ; 
for i = 1:N
    iwant(i) = sum(s(ib==i)) ; 
end
iwant

[Tehreem Syed]

Thanks, it was helpful.

[Tehreem Syed]

I can accept only one answer, all of the solutions were really helpful and correct for me.

Regards