almanac (version 0.1.1)

recur_on_mday: Recur on a day of the month

Description

recur_on_mday() recurs on a specific day of the month.

Usage

recur_on_mday(x, mday)

Value

An updated rrule.

Arguments

x

[rrule]

A recurrence rule.

mday

[integer]

The days of the month on which to recur. Negative values are allowed, which specify n days from the end of the month.

Details

If the day of the month doesn't exist for that particular month, then it is ignored. For example, if recur_on_mday(30) is set, then it will never generate an event in February.

Examples

# When used with a yearly or monthly frequency, `recur_on_mday()` expands the
# number of days in the event set.
on_yearly <- yearly()
on_yearly_mday_1_to_2 <- on_yearly %>% recur_on_mday(1:2)

start <- "1999-01-01"
end <- "2000-06-30"

alma_search(start, end, on_yearly)
alma_search(start, end, on_yearly_mday_1_to_2)

# When used with a daily frequency, `recur_on_mday()` limits the number of
# days in the event set.
on_daily <- daily()
on_daily_mday_1_to_2 <- on_daily %>% recur_on_mday(1:2)

length(alma_search(start, end, on_daily))
length(alma_search(start, end, on_daily_mday_1_to_2))

# Using a negative value is a powerful way to look back from the end of the
# month. This is particularly useful because months don't have the same
# number of days.
on_last_of_month <- monthly() %>% recur_on_mday(-1)

alma_search(start, end, on_last_of_month)

# If you want particular days of the week at the end of the month, you
# could use something like this, which checks if the end of the month
# is also a Friday.
on_last_of_month_that_is_also_friday <- on_last_of_month %>% recur_on_wday("Friday")
alma_search(start, end, on_last_of_month_that_is_also_friday)

# But you probably wanted this, which takes the last friday of the month,
# on whatever day that lands on
on_last_friday_of_month <- monthly() %>% recur_on_wday("Friday", -1)
alma_search(start, end, on_last_friday_of_month)