Seth Falcon wrote:
> Uwe Ligges <[EMAIL PROTECTED]> writes:
>
>>These are all dangerous, hence use the "safe" ways:
>>
>>sapply(a, is.null)
>>sapply(a, identical, "NULL")
>>sapply(a, is.na)
>>sapply(a, identical, "NA")
>
>
> Point taken, but is the behavior of as.character correct?
>
> as.character(list(NULL))
>
> as.character(NULL)
I thought about it quite a while. I think the current bahaviour is quite
OK. What should as.character do in the follwing case:
as.character(list("A", NA, NULL))
?
Note that it only can return a character vector...!
So, should it return a character vector of length 2? That's a bad idea,
if the length is reduced.
Moreover, as.character() does not get a NA or a NULL object for coercion
but an element of type list that itself conatins NA or NULL...
So if you want to convert a list to character and *keep* NA/NULL values,
you can only say:
lapply(a, as.character)
Uwe
> + seth
>
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