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: [email protected] [mailto:owner-
> [email protected]] On Behalf Of Kit Baum
> Sent: Thursday, April 14, 2005 9:43 PM
> To: [email protected]
> 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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