Times without dates
For this entire course, if you've ever had a time, it's always had an accompanying date, i.e. a datetime. But sometimes you just have a time without a date.
If you find yourself in this situation, the hms
package provides an hms
class of object for holding times without dates, and the best place to start would be with as.hms()
.
In fact, you've already seen an object of the hms
class, but I didn't point it out to you. Take a look in this exercise.
This is a part of the course
“Working with Dates and Times in R”
Exercise instructions
- Use
read_csv()
to read in"akl_weather_hourly_2016.csv"
.readr
knows about thehms
class, so if it comes across something that looks like a time it will use it. - In this case the
time
column has been parsed as a time without a date. Take a look at the structure of thetime
column to verify it has the classhms
. hms
objects print like times should. Take a look by examining the head of thetime
column.- You can use
hms
objects in plots too. Create a plot withtime
on the x-axis,temperature
on the y-axis, with lines grouped bydate
.
Hands-on interactive exercise
Have a go at this exercise by completing this sample code.
# Import auckland hourly data
akl_hourly <- read_csv(___)
# Examine structure of time column
str(___)
# Examine head of time column
head(___)
# A plot using just time
ggplot(akl_hourly, aes(x = ___, y = ___)) +
geom_line(aes(group = make_date(year, month, mday)), alpha = 0.2)