2020-07-31 Get rid of info of dplyr when grouping: `summarise()` regrouping output by 'species' (override with `.groups` argument)
2019-07-24 dplyr for programming
2017-06-17 dplyr 0.7.0 with great improvements for programming
2016-11-13 ggplot2: x-axis scale now available on all facet-columns
2016-05-08 RTFM or how to use spread of Hadley Wickham’s tidyr with a factor