On Wed, 11 Jul 2001, Agustin Lobo wrote:
>
> I've seen that:
>
> > min(c(NA,NA,NA),na.rm=T)
> [1] 2147483647
> Warning message:
> no finite arguments to min/max; returning extreme. in: min(..., na.rm >
na.rm)
>
> Would not be
>
> numeric(0)
>
> a more logical result?
It turns out that both NA and numeric(0) have disadvantages. The problem with
numeric(0) is that min() usually returns a vector of length 1 and doing
comparisons like (min(x)<max(y)) would lead to an error if one of them had
zero length. In many ways NA is the obvious result and is what S does, but using
Inf has the effect that max(c(x,y)) is always the same as max(x,max(y)) and
similar things.
The result is more elegant with real numbers where the result is the IEEE Inf
not just the largest number. Another minor advantage is that it automatically
gives the correct nonparametric confidence intervals for quantiles as having
infinite limits.
-thomas
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