possible bug: NULL equality in lists.
Uwe Ligges <ligges at statistik.uni-dortmund.de> writes:
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.
But consistent with vectorizing a list using unlist: unlist(list(NULL, NULL, "a")) [1] "a"
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...
In the case of NA, I think converting to "NA" should be a last resort. Since NA is a perfectly valid element of a character vector, it would seem to be a better choice.