Here's an example I tried:
This uses the 'tibble' package, which is an improvement on R data frames. The documentation states:
This is an S3 generic. tibble includes methods for data frames (adds tbl_df classes), tibbles (returns unchanged input), lists, matrices, and tables. Other types are first coerced via as.data.frame() with stringsAsFactors = FALSE.
I would expect that I could run the above because of that statement I bolded. I can do this:
I cannot do this: