Extract only quarter from a date in r

Question

I would like to extract ONLY the quarter from a date, e.g., to get an integer 1 from the date \"2003-02-08\". I have been trying something along this line

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Answer 1

There is a base R function, quarters, that more or less accomplishes what you want, though it prepends "Q". So

quarters(as.Date("2001-05-01"))
[1] "Q2"

If it is important to get rid of the "Q", you could use substr

substr(quarters(as.Date("2001-05-01")), 2, 2)
[1] "2"

Other date-related base R functions, such as weekdays and months can be found in help page ?quarters.