Fails for empty data.frame

[RomanTsegelskyi]

While writing some tests, I realized that pander fails for empty data.frames.

> mt <- mtcars[1:3, 1:4]
> mt
               mpg cyl disp  hp
Mazda RX4     21.0   6  160 110
Mazda RX4 Wag 21.0   6  160 110
Datsun 710    22.8   4  108  93
> mt[mt$mpg < 20, ]
[1] mpg  cyl  disp hp  
<0 rows> (or 0-length row.names)
> pander(mt[mt$mpg < 20, ])
Error in value[[jvseq[[jjj]]]] : subscript out of bounds

This doesn't seem to be super important (similar errors are in broom and ascii packages, thought xtable works correctly), but I will still investigate for a fix in the meantime

[daroczig]

Nice catch!

I think the xtable behavior (printing the header as a one-row table) is a nice solution, although I am not sure if we should print anything for objects without a real header, like:

> xtable::xtable(matrix(0, nrow = 0, ncol = 5))
% latex table generated in R 3.1.3 by xtable 1.7-4 package
% Tue Jun  9 20:42:55 2015
\begin{table}[ht]
\centering
\begin{tabular}{rrrrrr}
  \hline
 & 1 & 2 & 3 & 4 & 5 \\ 
  \hline
\hline
\end{tabular}
\end{table}

Probably I'd return nothing in such case. What do you think?

[RomanTsegelskyi]

It turns out there is actually a check for empty data.frames, just it's done too late, since the failure occurs earlier.

I like the current solution of assigning NA in case of empty object. And I agree that in case there is no header nothing should be printed, just like a warning produced. I have submitted a PR #182, let's move our discussion there.