[R-pkg-devel] tibbles are not data frames

On Tue, Sep 26, 2017 at 5:33 PM, Hadley Wickham <h.wickham at gmail.com> wrote:

I for one am happy this discussion pops up, because it's a piece of
information I give to my students as well: convert to a data.frame when
you
start your analysis just to play safe. And this discussion shows why
that is
-for the time being!- a good advice. The moment tibbles become the
default
data format in R, or some R++, or in Julia for all I care, I'll be more
than
happy to burn that drop = FALSE on a stake. But for now we can't ignore
the
differences and the potential for conflicts when you try to use a tibble
instead of a data.frame.

I think this is sub-optimal advice because most functions do work fine
with tibbles.

Most. Not all. Either tibbles work exactly like a data.frame, or they don't.
If they do, I wouldn't give that advice. But they don't.

It is only a few packages (largely written some time
ago) that don't. And typically, if they don't work with tibbles,
you'll get a (usually slightly confusing) error message because some
function will get a data frame instead of a vector. So as far I can
tell, you only need to as.data.frame() retrospectively, not
prospectively. Are you aware of any code that returns an incorrect
result (i.e. no error) when given a tibble instead of a data frame?

x <- tibble(a = 1:5, b = 5:1)

relcount <- function(x, id){
  table(x[,id]) / length(x[,id])
}
relcount(x, "a")
relcount(as.data.frame(x), "a")

You're welcome.