Computing stats by groups (II)

When grouping a data.table by multiple columns, you need to specify the by argument as either a character vector or a list. In this exercise, you will calculate the mean of duration for:

Each unique combination of start_station and end_station
Each start_station for each month

This exercise is part of the course

Data Manipulation with data.table in R

View Course

Hands-on interactive exercise

Have a go at this exercise by completing this sample code.

# Compute the mean duration for every start and end station
mean_station <- batrips[, ___, ___ = .(___, ___)]
mean_station

Edit and Run Code