cv = '000001010011100101111'
vect = [1 2 3];
groupsize = 3;
assert(mod(numel(cv), groupsize) == 0, 'Input cannot be divided evenly into groups of %d elements', groupsize);
prefix = reshape(cv, groupsize, []); %reshape input into columns of groupsize elements
postfix = char(repmat(vect + '0', 1, ceil(size(prefix, 2)/groupsize))); %replicate vect to be at least as long as prefix, and convert to char
postfix = postfix(1:size(prefix, 2)); %truncate unneeded elements
result = reshape([prefix; postfix], 1, []) %concatenate and reshape into one row
