John Mount builds a function to improve upon the group-by to mutate model in dplyr:
The advantages of the shorthand are:
- The analyst only has to specify the grouping column once.
- The data (
mtcars) enters the pipeline only once.
- The analyst doesn’t have to start thinking about joins immediately.
Frankly I’ve never liked the shorthand. I feel it is a “magic extra” that a new user would have no way of anticipating from common use of
summarize(). I very much like the idea of wrapping this important common use case into a single verb. Adjoining “windowed” or group-calculated columns is a common and important step in analysis, and well worth having its own verb.
Below is our attempt at elevating this pattern into a packaged verb.
Click through for the script. I’d like to see something like this make its way into dplyr.