Rounding with the weather data
When is rounding useful? In a lot of the same situations extracting date components is useful. The advantage of rounding over extracting is that it maintains the context of the unit. For example, extracting the hour gives you the hour the datetime occurred, but you lose the day that hour occurred on (unless you extract that too), on the other hand, rounding to the nearest hour maintains the day, month and year.
As an example you'll explore how many observations per hour there really are in the hourly Auckland weather data.
Diese Übung ist Teil des Kurses
Working with Dates and Times in R
Anleitung zur Übung
- Create a new column called
day_hour
that isdatetime
rounded down to the nearest hour. - Use
count()
onday_hour
to count how many observations there are in each hour. What looks like the most common value? - Extend the pipeline, so that after counting, you filter for observations where
n
is not equal to2
.
Interaktive Übung
Versuche dich an dieser Übung, indem du diesen Beispielcode vervollständigst.
# Create day_hour, datetime rounded down to hour
akl_hourly <- akl_hourly %>%
mutate(
day_hour = ___(datetime, unit = ___)
)
# Count observations per hour
akl_hourly %>%
count(___)
# Find day_hours with n != 2
akl_hourly %>%
count(___) %>%
filter(___) %>%
arrange(desc(n))