Re: st: RE: Taking averages, etc.

[Richard Williams <Richard.A.Williams.5@nd.edu>]

At 01:24 PM 12/17/2003 -0500, David Kantor wrote:
> I have written about this previously, but I feel compelled to state this 
> again.  Some of us may find it confusing, but I always do these kinds of 
> operations using nested cond() functions:
>
> #delimit ;
> gen Y =
> cond(X1 == 1 & X2 == 3, 3,
> cond(X3 == 2  & X4 == 17, 4,
>  5));
I like this!  It seems to do exactly what I had in mind in terms of being a 
counterpart to the SPSS DO IF command.  I believe it is also very similar 
to how you would do this in Excel if you were trying to fit the formula 
into a cell instead of writing a macro. My only objection, as you also 
note, is that this syntax is harder to read than the SPSS counterpart, but 
splitting things up onto separate lines probably helps.


> As Fred wrote:
>
> gen y = 3 if X1==1 & X2==3
> replace y = 4 if X1 !=1 & X2 !=3 & X3==2 & X4==17
> replace y = 5 if X1 !=1 & X2 !=3 & X3 !=2 & X4 !=17
>
> First, this needs a correction:
Actually, I made the mistake, not Fred :) But I think this underscores that 
it would be easy (at least for somebody like me) to make coding mistakes if 
there were a lot of conditions involved.


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