Encoding your flight data
You're ready to encode your data to an xts
object! Remember that flights
is a data frame containing four columns of flight data and one column of dates.
To convert to an xts
object, you'll need to ensure that your date column is in a time-based format. As you discovered earlier, the date
column is currently a character
. Once date
is saved in a time-based format, you're ready to convert to xts! To do so, you'll use as.xts()
, which takes two primary arguments.
First, you'll need to specify the object being converted (in this case, flights
). To avoid redundancies, you should generally remove the time-based column from the data when you convert to xts
. In this case, you'll remove the fifth column (dates
), by specifying [, -5]
in your as.xts()
call.
Second, you'll need to tell xts how to index your object by specifying the order.by
argument. In this case, you want to index your object on the date
column.
The flights
data frame is preloaded for you.
This exercise is part of the course
Case Study: Analyzing City Time Series Data in R
Exercise instructions
- Load the
xts
package. - Use as.Date() to convert the
date
column inflights
from acharacter
to aDate
object. - Convert your data to an
xts
object usingas.xts()
. To do so, you'll need to specify the data being encoded followed by theorder.by
argument, which generates the time-based index. Save this object asflights_xts
. - Check the class of
flights_xts
in your workspace. - Examine the first
5
rows offlights_xts
.
Hands-on interactive exercise
Have a go at this exercise by completing this sample code.
# Load the xts package
# Convert date column to a time-based class
flights$date <- ___(flights$date)
# Convert flights to an xts object using as.xts
flights_xts <- as.xts(___ [ , -___], order.by = ___)
# Check the class of flights_xts
# Examine the first five lines of flights_xts