[R] as.integer question

Peter Dalgaard P.Dalgaard at biostat.ku.dk
Thu Jan 17 18:54:35 CET 2008


Erin Hodgess wrote:
> Hi R People:
>
> I'm reading "Statistical Computing with R", by Maria Rizzo, and it's
> really good.
>
> Anyhow, I have a question about something in there.
>
>   
>> u <- runif(5)
>> u
>>     
> [1] 0.1177041 0.4271790 0.4601597 0.2204846 0.4051473
>   
>> #in the book
>> sum(as.integer(u > 0.4))
>>     
> [1] 3
>   
>> #what I would do
>> sum(u > 0.4)
>>     
> [1] 3
>   
>
> Is one way better than the other, please?
>
> Thanks,
> Erin
>
>   
I'd do what you'd do, but I suppose that the author felt that it was
clearer to make the coercion explicit. In terms of speed, your version
is likely faster (but what would you do with those extra 17 microseconds
of life?).

-p

-- 
   O__  ---- Peter Dalgaard             Øster Farimagsgade 5, Entr.B
  c/ /'_ --- Dept. of Biostatistics     PO Box 2099, 1014 Cph. K
 (*) \(*) -- University of Copenhagen   Denmark          Ph:  (+45) 35327918
~~~~~~~~~~ - (p.dalgaard at biostat.ku.dk)                  FAX: (+45) 35327907




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