Re: st: RE: re: cond(a,b,c) fn

[James Cui <james.cui@med.monash.edu.au>]

Thanks for the input. You are right "x" is an expression, not a 
variable. Good judgment comes from good experience and good experience 
comes from bad experience!

James.

Email: James.Cui@med.monash.edu.au



Scott Merryman wrote:

> A couple other ways:
>
> gen a = cond(rep78==1, 1, 0 ) if rep !=.
>
>
> gen a = cond(rep, cond(rep ==1, 1, 0), 0, .)
>
> Scott
>
>
> > -----Original Message-----
> > From: owner-statalist@hsphsun2.harvard.edu [mailto:owner-
> > statalist@hsphsun2.harvard.edu] On Behalf Of Kit Baum
> > Sent: Thursday, April 14, 2005 9:43 PM
> > To: statalist@hsphsun2.harvard.edu
> > Subject: st: re: cond(a,b,c) fn
> >
> > James writes
> >
> > When I use the cond(x,a,b,c) function, I could not generate the value c
> > when x is missing. For example:
> >
> > sysuse auto, clear
> > tab rep78, mi
> > gen a=cond(rep78==1, 1, 0, .)
> > tab a, mi
> >
> > It gives
> >
> > a	Freq.	Percent	Cum.
> >
> > 0	72	97.30	97.30
> > 1	2	2.70	100.00
> >
> > Total	74	100.00
> >
> > There should be 5 missing values for variable a according to the manual.
> > Thanks for your input.
> >
> >
> >
> > The online help says
> >
> >  cond(x,a,b,c) returns a if x evaluates to true (not 0), b if x
> > evaluates to false
> >         (0), and c if x evaluates to missing (.).
> >
> > Since "rep78==1" never evaluates to missing, a will never be set to
> > missing.
> > A way to achieve this is
> >
> > . g a = (rep78==1)*rep78/rep78
> >
> > . tab a,mi
> >
> >           a |      Freq.     Percent        Cum.
> > ------------+-----------------------------------
> >           0 |         67       90.54       90.54
> >           1 |          2        2.70       93.24
> >           . |          5        6.76      100.00
> > ------------+-----------------------------------
> >       Total |         74      100.00
> >
> > Kit Baum, Boston College Economics
> > http://ideas.repec.org/e/pba1.html
> >
> > *
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>
>
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