take certain elements from an array

Question

is there an easy way to select let's say every 2 elements from an array taking the first nonzero element. My array is sparse double. For example:

val =

     (1,1)             0.1667
     (2,1)             0.1667
     (3,1)             0.1667
     (4,1)             0.1667
     (5,1)             0.1667
     (6,1)             0.1667
     (7,1)             0.1667
     (8,1)             0.1667

So I want to run my code taking 2 values in, next two values out and so on. Like this:

val = 
     (1,1)             0.1667
     (2,1)             0.1667
     (5,1)             0.1667
     (6,1)             0.1667

Below is my code, let's say I want to select every 2 elements starting from the first nonzero element.

results=zeros(86400,1); % time of the day in seconds
for i=1:28,
    currentFlowArray=allFileMin(i).demand_pattern1.Wm.total.flowArray;
    for p=1:86400,
        results(p)=results(p)+ currentFlowArray(p);
    end
end

Hope I was clear! Thank you in advance!

Answer 1

To get the values out of val:

valnz = nonzeros(val);
result = valnz(sort([1:4:nnz(val) 2:4:nnz(val)]));

To remove make the non-desired values within val:

ind = find(val);
val(ind(sort([3:4:numel(ind) 4:4:numel(ind)]))) = 0;