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Is the calendar year a leap year?

Source: R/calendar.R
calendar_leap_year.Rd

calendar_leap_year() detects if the calendar year is a leap year - i.e. does it contain one or more extra components than other years?

A particular year is a leap year if:

  • year_month_day(): February has 29 days.

  • year_month_weekday(): February has a weekday that occurs 5 times.

  • year_week_day(): There are 53 weeks in the year, resulting in 371 days in the year.

  • iso_year_week_day(): There are 53 weeks in the year, resulting in 371 days in the year.

  • year_quarter_day(): One of the quarters has 1 more day than normal (the quarter with an extra day depends on the start used, but will always be the same for a particular start). This aligns with Gregorian leap years for all starts except February, in which case the leap year is always 1 year after the Gregorian leap year.

  • year_day(): There are 366 days in the year.

Usage

calendar_leap_year(x)

Arguments

x

[calendar]

A calendar type to detect leap years in.

Value

A logical vector the same size as x. Returns TRUE if in a leap year, FALSE if not in a leap year, and NA if x is NA.

Examples

x <- year_month_day(c(2019:2024, NA))
calendar_leap_year(x)
#> [1] FALSE  TRUE FALSE FALSE FALSE  TRUE    NA

# For year-quarter-day, the leap year typically aligns with the Gregorian
# leap year, unless the `start` is February, in which case the leap year is
# always 1 year after the Gregorian leap year
x <- year_quarter_day(2020:2021, start = clock_months$january)
calendar_leap_year(x)
#> [1]  TRUE FALSE

x <- year_quarter_day(2020:2021, start = clock_months$february)
calendar_leap_year(x)
#> [1] FALSE  TRUE

# With a January start, 2020 has the extra day
get_day(year_quarter_day(2020, 1:4, "last", start = clock_months$january))
#> [1] 91 91 92 92
get_day(year_quarter_day(2021, 1:4, "last", start = clock_months$january))
#> [1] 90 91 92 92
get_day(year_quarter_day(2022, 1:4, "last", start = clock_months$january))
#> [1] 90 91 92 92

# With a February start, 2021 has the extra day
get_day(year_quarter_day(2020, 1:4, "last", start = clock_months$february))
#> [1] 89 92 92 92
get_day(year_quarter_day(2021, 1:4, "last", start = clock_months$february))
#> [1] 90 92 92 92
get_day(year_quarter_day(2022, 1:4, "last", start = clock_months$february))
#> [1] 89 92 92 92