I'm trying to knit the Rmd file, but the following message shows:
Error: 'data_frame' is not an exported object from 'namespace:vctrs'
So I couldn't knit.
I believe the functions that caused this are the group_by() and summarise() functions.
My dplyr version is 0.8.5
vctrs version is 0.2.4
R version is 3.5.3
Any suggestions? Thank you!