radjusted: Create an adjusted rschedule

In almanac: Tools for Working with Recurrence Rules

Create an adjusted rschedule

Description

radjusted() creates a new adjusted rschedule on top of an existing one. The new rschedule contains the same event dates as the existing rschedule, except when they intersect with the dates in the event set of the rschedule, adjust_on. In those cases, an adjustment is applied to the problematic dates to shift them to valid event dates.

This is most useful when creating corporate holiday rschedules. For example, Christmas always falls on December 25th, but if it falls on a Saturday, your company might observe Christmas on the previous Friday. If it falls on a Sunday, you might observe it on the following Monday. In this case, you could construct an rschedule for a recurring event of December 25th, and a second rschedule for weekends. When Christmas falls on a weekend, you would apply an adjustment of adj_nearest() to get the observance date.

Usage

radjusted(rschedule, adjust_on, adjustment)

Arguments

rschedule	⁠[rschedule]⁠ An rschedule, such as an rrule, runion, rintersect, or rsetdiff.
adjust_on	⁠[rschedule]⁠ An rschedule that determines when the adjustment is to be applied.
adjustment	⁠[function]⁠ An adjustment function to apply to problematic dates. Typically one of the pre-existing adjustment functions, like adj_nearest(). A custom adjustment function must have two arguments x and rschedule. x is the complete vector of dates that possibly need adjustment. rschedule is the rschedule who's event set determines when an adjustment needs to be applied. The function should adjust x as required and return the adjusted Date vector.

Value

An adjusted rschedule.

Examples

since <- "2000-01-01"
until <- "2010-01-01"

on_christmas <- yearly(since = since, until = until) %>%
  recur_on_month_of_year("Dec") %>%
  recur_on_day_of_month(25)

# All Christmas dates, with no adjustments
alma_events(on_christmas)

on_weekends <- weekly(since = since, until = until) %>%
  recur_on_weekends()

# Now all Christmas dates that fell on a weekend are
# adjusted either forwards or backwards, depending on which
# non-event date was closer
on_adj_christmas <- radjusted(on_christmas, on_weekends, adj_nearest)

alma_events(on_adj_christmas)

almanac documentation built on April 14, 2023, 12:23 a.m.