Date formatting MMM-YYYY

Question

I have a dataset with dates in following format:

Initial:

Jan-2015 Apr-2013 Jun-2014 Jan-2015 Jan-2016 Jan-2015 Jan-2016 Jan-2015 Apr-2012 Nov-2012 Jun-2         


        

Answer 1

To expand on @neilfws answer, you can use the month and year functions from the lubridate package to create your dummy variables with the month and year in your data frame.

Here is the code:

library(lubridate)
library(zoo)
df <- data.frame(Initial = c("Jan-2015", "Apr-2013", "Jun-2014", "Jan-2015", "Jan-2016", "Jan-2015", 
                         "Jan-2016", "Jan-2015", "Apr-2012", "Nov-2012", "Jun-2013", "Sep-2013"),
             Final = c("Feb-2014", "Jan-2013", "Sep-2014", "Apr-2013", "Sep-2014", "Mar-2013", 
                       "Aug-2012", "Apr-2012", "Oct-2012", "Oct-2013", "Jun-2014", "Oct-2013"))

df$Initial <- as.character(df$Initial)
df$Final <- as.character(df$Final)
df$Initial <- as.yearmon(df$Initial, "%b-%Y")
df$Final <- as.yearmon(df$Final, "%b-%Y")
df$month_initial <- month(df$Initial)
df$year_intial <- year(df$Initial)
df$month_final <- month(df$Final)
df$year_final <- year(df$Final)

df$Difference <- 12*(df$Initial-df$Final)

And here is the final data.frame:

> head(df)
   Initial    Final month_initial year_intial month_final year_final Difference
1 Jan 2015 Feb 2014             1        2015           2       2014         11
2 Apr 2013 Jan 2013             4        2013           1       2013          3
3 Jun 2014 Sep 2014             6        2014           9       2014         -3
4 Jan 2015 Apr 2013             1        2015           4       2013         21
5 Jan 2016 Sep 2014             1        2016           9       2014         16
6 Jan 2015 Mar 2013             1        2015           3       2013         22

Hope this helps!

Answer 2

You could use as.yearmon from the zoo package for this.

library(zoo)
12 * (as.yearmon("Jan-2015", "%b-%Y") - as.yearmon("Feb-2014", "%b-%Y"))

# result
# [1] 11