Subtracting months - issue with last day of month?

Question

Quick question on dates in R. Check out this snippet of code:

Sys.Date() - months(3)
# [1] \"2013-12-31\"
Sys.Date() - months(18)
# [1] NA

Answer 1

Similarly if you want to have an increment of 3 months, it can be done as follows:

PW_Data_Plan_V1$Month = as.Date(PW_Data_Plan_V1$DOJ) %m+% months(3)