Extend vector with NaN at specific points

Hi there, I've got two vectors, RTdata(1x3120 double) and outcomeflat(1x3024). I basically want to add a NaN to the vector outcomeflat if there is one present in the same element in RTdataflat, AND if there is not already a NaN present at that positiion in outcomeflat. So e.g.

RTdataflat = [1 2 3 NaN 5 6 NaN 8 9 NaN]
outcomeflat = [3 4 7 NaN 9 2 8 9]

I'd want to convert outcomeflat to

outcomeflat = [3 4 7 NaN 9 2 NaN 8 9 NaN]

So far I tried to use this:

nan_locations = isnan(RTdataflat)
for n = 1:3120
    if nan_locations(n) == 1
        if outcomeflat(n) ~= NaN
        b = NaN;
        outcomeflat = cat(2, outcomeflat(1:n), b, outcomeflat(n:end));
        end 
    end 
end     

However this outputs outcomeflat as a 1x3740 vector, as opposed to the 1x3120 vector that I need/expected. I'm not sure why the second if statement doesn't prevent this. I tried putting it in the same if statement using && however this produced the same result

Thanks!

Answer 1

[Daniel Catton]

I've been able to come up with this code, it follows my understanding of the problem given your example:

RTdataflat = [1 2 3 NaN 5 6 NaN 8 9 NaN];
outcomeflat = [3 4 7 NaN 9 2 8 9];
%Define your vectors

[Rx,Ry] = size(RTdataflat);
[ox,oy] = size(outcomeflat);
%Gets sizes of the vectors

q =Ry-oy;
    outcomeflat(end+q) = 0;
%Pre-allocates some extra space in outcomeflat for the NaN variables

    for b = 1:Ry
        if isnan(RTdataflat(Rx,b))
            if ~isnan(outcomeflat(Rx,b))
            for c = flip(b:Ry)
            outcomeflat(1,c) = outcomeflat(1,c-1); %Moves all data to allow space for NaN if data does not contain NaN already
            end
            end
            outcomeflat(Rx,b) = NaN; %Adds NaN into the vector
        end
    end

%Returns the vector [3,4,7,NaN,9,2,NaN,8,9,NaN] as requested.

[Owen Gray]

This is great thank you so much!!! Really appreciate it and makes sense cheers, worked perfectly