st: Mata question on replacing missing values

[Matthew Baker <matthew.baker@hunter.cuny.edu>]

Dear Listers:

     I am curious if there is a simple solution to the following
problem in Mata. I have two vectors (call them X and Y). X has missing
values, while Y does not. What I would like to do is make a third
vector, Z, which is composed of X when the value of X is not missing,
and Y otherwise. For example, if I have X=(5,6,.,.,4)', and
Y=(1,5,3,2,3)', I would like Z to be Z=(5,6,3,2,4)'. In order:


: X,Y,Z
       1   2   3
    +-------------+
  1 |  5   1   5  |
  2 |  6   5   6  |
  3 |  .   3   3  |
  4 |  .   2   2  |
  5 |  4   3   4  |
    +-------------+

Is there a simple solution?

Thanks in advance,

Matt Baker

-- 
Dr. Matthew J. Baker
Department of Economics
Hunter College and the Graduate Center, CUNY
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