How to extract year of birth from a “YYYY-MM-DD” string variable in R? [duplicate]

问题

This question already has answers here:

Extract year from date (6 answers)

Closed 2 years ago.

I've seen several entries here on a similar question yet on different platforms - i.e. not using R.

My question, in brief, is: How do I take only the year info from a string variable that also contains the month and day of birth?

Example:

    born_in
1   "1974-12-18"
2   ...

Thank you in advance!

回答1:

Here's a single line:

format(as.Date("1974-12-18"),"%Y")

回答2:

Maybe this will help:

 born_in <- "1974-12-18"
 born_in_date <- as.Date(born_in)
 year(born_in_date)

来源：https://stackoverflow.com/questions/47597010/how-to-extract-year-of-birth-from-a-yyyy-mm-dd-string-variable-in-r