calculate X months after the specific date.

"seq" function included in mondate library is enhanced to calculate the distance of months between two dates. This is not possible in the standard "seq" function. Please don't forget to load mondate library beforehand.


> seq(mondate("2009/12/31"), by=1, length.out=8)[8]
mondate: timeunits="months"
[1] 2010/07/31