# RE: st: combining two variables

 From "Nick Cox" To Subject RE: st: combining two variables Date Wed, 7 Mar 2007 17:14:51 -0000

```Some very complicated solutions here!

Consider:

gen newvar = max(var1, var2) if missing(var1, var2)

Logic:

If just one of var1 or var2 is missing,
then -missing()- will return true.

In that case, max(var1, var2) will
return the non-missing value in question.

If both are missing, then you get missing returned,
but that is fair enough.

If neither is missing, missing is returned.

Nick
n.j.cox@durham.ac.uk

Paswel Phiri Marenya

> What to me is easier is something like:
>
> gen var3 = var2
> then replace var3=var1 in 4/5 and so on...although with a
> long data set it
> may be tedious perhaps.
> PPm
>
> > Thank you to everyone who answered my last question on
> > creating a variable corresponding to the row number.
> >
> > Now I have a question about combining the data from two
> > variables (in the same data set) into one variable. I want to
> > combine the variables in such a way that the data from one
> > variable can replace the missing values from the other. I have
> > created an example of what I am looking for below:
> >
> >
> >            Have:                   Want:
> >       var1       var2              newvar
> >         .          2                 2
> >         .          8                 8
> >         .          0                 0
> >         7          .                 7
> >         3          .                 3
> >         .          .                 .
> >
> > Any thoughts on how to do this?

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```