event-mday-in-month: Events related to a specific day in a month

In DavisVaughan/almanac3: Tools for Adjusting and Generating Dates Using a Grammar of Schedules

Description

• before_mday_in_month(): Is the date before the day of the month mday in month month?

• after_mday_in_month(): Is the date after the day of the month mday in month month?

• between_mdays_in_months(): Is the date between the day of the month x_mday in month x_month and y_mday in month y_month?

These functions are convenient helpers for defining events such as "before January 24th". They are constructed from lower level event creators, but are common enough to stand alone.

Usage

after_mday_in_month(month, mday, inclusive = FALSE)

before_mday_in_month(month, mday, inclusive = FALSE)

between_mdays_in_months(x_month, x_mday, y_month, y_mday)

Arguments

month, x_month, y_month	[integer(1) / character(1)] A month of the year. Combined with mday, this uniquely defines a specific day of a specific month, such as "January 24".
mday, x_mday, y_mday	[integer(1)] A day of the month.
inclusive	[logical(1)] Should the date defined by month and mday count as an event?

Examples

# Any day before Feb 25th
before_feb_25 <- before_mday_in_month("Feb", 25)

event_in("2019-01-01", before_feb_25)
event_in("2019-01-26", before_feb_25)

# You might think that you could construct this helper
# from these two lower level event helpers
bad_before_feb_25 <- before_mday(25) & before_month("Feb")

# But the logic isn't right! It works when both conditions are true,
# but Jan-26 is before Feb-25, but registers as a non-event with this logic
# because 26 > 25.
event_in("2019-01-01", bad_before_feb_25)
event_in("2019-01-26", bad_before_feb_25)

# The actual condition is more like:
strictly_before_feb <- before_month("Feb", inclusive = FALSE)
in_feb_and_before_25th <- on_month("Feb") & before_mday(25)
good_before_feb_25 <- strictly_before_feb | in_feb_and_before_25th

event_in("2019-01-01", good_before_feb_25)
event_in("2019-01-26", good_before_feb_25)

# This pattern can be used to construct other similar helpers that
# we have chosen not to export, but still might be useful. For example:
# "After the 15th day in the 2nd quarter"
strictly_after_q2 <- after_quarter(2, inclusive = FALSE)
in_q2_and_after_15th_qday <- on_quarter(2) & after_qday(15)
after_15th_day_in_q2 <- strictly_after_q2 | in_q2_and_after_15th_qday

event_in(as.Date("2019-04-01") + days(14), after_15th_day_in_q2)
event_in(as.Date("2019-04-01") + days(15), after_15th_day_in_q2)

DavisVaughan/almanac3 documentation built on Oct. 30, 2019, 5:59 a.m.