Combining i, j, and by (I)
In this exercise, you will combine the i, j, and by arguments to find the first and last ride for each start station. Recall that data.table first filters the rows in i, and then groups the rows using by, and finally compute the expression in j.
Este exercício faz parte do curso
Data Manipulation with data.table in R
Instruções do exercício
- Arrange
batripsusing thestart_datecolumn in ascending order. - Group the rows by
start_station. - Extract the first and last rows of
start_date.
Exercício interativo prático
Experimente este exercício completando este código de exemplo.
# Find the first and last ride for each start_station
first_last <- batrips[___,
.(start_date = ___),
by = ___]
first_last