How to replace ones and zeros in a logical vector with vectors of corresponding length?

I need to recombine two vectors which where seperatet by logical indexing:

idx = [1 0 0 1 1 0 0]; % appearance of logical index
a = [2 3 4];           % the values of a have to replace the ones in indx in the same order
b = [9 8 7 7];         % the values of b have to replace the zeros in indx in the same order

The solution should look like this:

c = [2 9 8 3 4 7 7];   % recombined vector

Answer 1

[Scott MacKenzie]

idx = [1 0 0 1 1 0 0]; % appearance of logical index
a = [2 3 4];           % the values of a have to replace the ones in indx in the same order
b = [9 8 7 7]; 

c = [a b];
idx = logical(idx);
c = [c(idx) c(~idx)]

c = 1×7

2 9 8 3 4 7 7

[Edward Schreiner]

Thank you too! I'll accept this as i find it even more elegant.

Answer 2

[Yongjian Feng]

Try this:

idx = [1 0 0 1 1 0 0]; % appearance of logical index
a = [2 3 4];           % the values of a have to replace the ones in indx in the same order
b = [9 8 7 7];         % the values of b have to replace the zeros in indx in the same order

c = [];
aIdx = 1;
bIdx = 1;
for i=1:length(idx)
    if idx(i) == 1
        c(end+1)=a(aIdx);
        aIdx = aIdx + 1;
    else
        c(end+1) = b(bIdx);
        bIdx = bIdx + 1;
    end
end
c

[Edward Schreiner]

Thank you a lot! It works as intended.