Exercise

Using .SD (I)

.SD together with .SDcols is an incredibly powerful feature that makes computing on multiple columns so much easier.

.SD is a special symbol which stands for Subset of Data
.SDcols holds the columns that should be included in .SD

Instructions

100 XP

For each month, find the row corresponding to the shortest trip (by using which.min() on duration).
The result should contain the month, start_station, end_station, start_date, end_date, and duration columns.