Nicholas Lewin-Koh wrote:
Hi
the following example I think demonstrates the inconsistency
f<-function(x) x
length(f)
[1] 1
is.na(f)
[1] FALSE
Warning message:
In is.na(f) : is.na() applied to non-(list or vector) of type 'closure'
The documentation states:
Arguments
x an R object to be tested.
value a suitable index vector for use with x.
And nowhere in the details was it implied (to me anyway) that x could
not be a function
or anything else in R for that matter. Did I miss something?
Well, it's just a warning which you get whenever you apply is.na to
things that cannot logically be NA, e.g.
> is.na(.GlobalEnv)
[1] FALSE FALSE
Warning message:
In is.na(.GlobalEnv) :
is.na() applied to non-(list or vector) of type 'environment'
> is.na(quote(a))
[1] FALSE
Warning message:
In is.na(quote(a)) :
is.na() applied to non-(list or vector) of type 'symbol'
> is.na(quote(`NA`))
[1] FALSE
Warning message:
In is.na(quote(`NA`)) :
is.na() applied to non-(list or vector) of type 'symbol'
> is.na(is.na)
[1] FALSE
Warning message:
In is.na(is.na) : is.na() applied to non-(list or vector) of type 'builtin'
I suppose the documentation could be more explicit about it, but where's
the need?
--
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.dalga...@biostat.ku.dk) FAX: (+45) 35327907
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