The best way to get years between two dates in R

Question

I'd like to calculate a difference between two dates in years with decimal values. Let's say we have "1978-08-25" and "2014-02-05" (%Y-%m-%d). How can I calculate the difference between these two dates in years with decimal values (ie. not just 35 years, but 35.95...years)? Thank you in advance.

somewhat close: `as.integer(as.Date("2014-02-05") - as.Date("1978-08-25")) / 365.25` — flodel, Feb 06 '14 at 00:21

score 3 · Answer 1 · answered Feb 06 '14 at 00:33

3

You could check out the zoo package.

x = as.yearmon("2014-02-05")
y = as.yearmon("1978-08-25")

x - y
[1] 35.5

answered Feb 06 '14 at 00:33

AGS

14,288
5
52
67

score 1 · Answer 2 · answered Feb 06 '14 at 01:29

It's probably worth noting that this really can't be answered definitively (as @hadley alluded to). Even the base difftime function in R only allows the options of:

...units = c("auto", "secs", "mins", "hours", "days", "weeks"))

No months, no years, because they are not definite values. Having said that, you can closely approximate something sensible using @flodel's method in the comments.

The best way to get years between two dates in R

2 Answers2

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