MATLAB: How to compare two arrays

Question

Example:

 aa = [1 1 1 1 -1 -1 1 1 1 1 1 1 -1 -1 1]

and

 bb = [NaN NaN NaN NaN 0.2 0.3 NaN 0.2 0.3 NaN NaN NaN 0.2 0.3 NaN]

and I want to generate third array such that it contains values in bb for every value that correspond to -1 in aa, and for every other value I should get NaN, and the size of resulted should remain same as aa and bb. So the result should look something like this:

cc = [NaN NaN NaN NaN 0.2 0.3 NaN NaN NaN NaN NaN NaN 0.2 0.3 NaN].

I am doing something like this:

cc = bb(aa == -1 | isnan(bb));

But the length or the size of the array changes.

Please advice.

Answer 1

Try this:

cc = nan(1, length(bb))
cc(aa==-1) = bb(aa==-1)

In the command window:

cc =
         NaN       NaN       NaN       NaN    0.2000    0.3000       NaN       NaN       NaN       NaN       NaN       NaN    0.2000    0.3000       NaN