Practical Predictive Analytics

Converting the dataframe to a time series object

As a preparation step, we will use the ts function to convert our dataframe to a time series object. It is important that the time series be equally spaced before converting to a ts object. At a minimum, you supply the time series variable, and start and end dates as arguments to the ts function.

After creating a new object, x, run a str() function to verify that all of the 14 time series from 1999 to 2012 have been created:

# only extract the 'ALL' timeseriesx <- ts(x2$Not.Covered.Pct[1:14], start = c(1999), end = c(2012), frequency = 1)str(x) >  Time-Series [1:14] from 1999 to 2012: 0.154 0.157 0.163 0c.161 0.149 ...