[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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