Calculate ages in R

Question

I have two data frames in R. One frame has a persons year of birth:

YEAR
/1931
/1924

and then another column shows a more recent time.

Answer 1

You can do some formating:

as.numeric(format(as.Date("01/01/2010", format="%m/%d/%Y"), format="%Y")) - 1930

With your data:

> yr <- c(1931, 1924)
> recent <- c("09/08/2005", "11/08/2005")
> as.numeric(format(as.Date(recent, format="%m/%d/%Y"), format="%Y")) - yr
[1] 74 81

Since you have your data in a data.frame (I'll assume that it's called df), it will be more like this:

as.numeric(format(as.Date(df$recent, format="%m/%d/%Y"), format="%Y")) - df$year