Find leap-day (Feb 29) indices in a date vector

Scans a vector of dates and returns the integer indices of all elements that correspond to February 29. If the vector contains no leap days, returns NULL.

Usage

find_leap_day_indices(date)

Arguments

date

A vector coercible to Date.

Value

Integer vector of indices where dates equal February 29, or NULL if none.

Examples

find_leap_day_indices(as.Date(c("1980-02-28", "1980-02-29", "1981-01-01")))
#> [1] 2
find_leap_day_indices(as.Date(c("2001-01-01", "2001-12-31")))
#> NULL