Roll scheduled events

Given a schedule of events, create a new schedule where the events are adjusted according to some rule.

roll_by() adjusts the events of a schedule by some incremental period.
roll_forward() and roll_backward() adjust the events of a schedule to the nth previous/next occurrence of some other scheduled event.

roll_by(x, n, unit, .p = NULL)

roll_forward(x, to_schedule, n = 1, .p = NULL)

roll_backward(x, to_schedule, n = 1, .p = NULL)

Arguments

x	The schedule of events to adjust.
n	The increment of the event adjustment. For `roll_by()` this is the increment of the `unit` period to adjust the events by. Eg. `2` to adjust the events two `unit` periods into the future or `-3` to adjust the events three unit periods into the past. For `roll_forward()` and `roll_backward()`, `n` defaults to 1, indicating the schedule should be adjusted to the `to_schedule` event immediately preceding/following the events of `x`. If more than 1, will skip n-1 occurrences.
unit	A character shortcut for a period object. Eg. "year", "years", "month", "months", "week", "weeks" etc. Can be any value accepted by `lubridate::period()`.
.p	Optionally, a schedule to use for limiting the adjustment performed on `x`. Events falling on `.p` will be adjusted. Events not falling on `.p` will be returned unadjusted in the output schedule. Leave `NULL` (the default) to adjust all the events of `x`. Eg. `roll_forward(x, to_schedule = on_wday("Sun"))` rolls the events of `x` to the next Sunday.
to_schedule	A schedule to which events can be rolled.

Value

A schedule object.

Examples


library(lubridate, warn.conflicts = FALSE)
library(magrittr, warn.conflicts = FALSE)

# Imagine you get paid on the 25th of the month

on_payday <- on_mday(25)

schedule_days(on_payday, during = 2000)
#>  [1] "2000-01-25" "2000-02-25" "2000-03-25" "2000-04-25" "2000-05-25"
#>  [6] "2000-06-25" "2000-07-25" "2000-08-25" "2000-09-25" "2000-10-25"
#> [11] "2000-11-25" "2000-12-25"

# Except if your payday falls on a weekend, in which case it moves to the
# next weekday

on_payday %>%
  roll_forward(to = on_weekday(), .p = on_weekend()) %>%
  schedule_days(during = 2000)
#>  [1] "2000-01-25" "2000-02-25" "2000-03-27" "2000-04-25" "2000-05-25"
#>  [6] "2000-06-26" "2000-07-25" "2000-08-25" "2000-09-25" "2000-10-25"
#> [11] "2000-11-27" "2000-12-25"

# For some people payday may adjust to the previous weekday if it falls on
# a weekend

on_payday %>%
  roll_backward(to = on_weekday(), .p = on_weekend()) %>%
  schedule_days(during = 2000)
#>  [1] "2000-01-25" "2000-02-25" "2000-03-24" "2000-04-25" "2000-05-25"
#>  [6] "2000-06-23" "2000-07-25" "2000-08-25" "2000-09-25" "2000-10-25"
#> [11] "2000-11-24" "2000-12-25"

# Imagine the garbage truck normally comes every Monday, but if
# Monday is a state holiday, then it comes on Tuesday instead.

on_labor_day <-
  on_first(on_wday("Mon"), within_given = "month") %>%
  only_occur(in_month("Sep"))

on_christmas_day <- only_occur(in_month("Dec"), on_mday(25))

on_non_working_day <-
  on_weekend() %>%
  also_occur(on_labor_day) %>%
  also_occur(on_christmas_day)

on_my_business_day <- dont_occur(on_non_working_day)

on_normal_trash_day <- on_wday("Mon")

on_trash_day <-
  on_normal_trash_day %>%
  roll_forward(to_schedule = on_my_business_day, .p = on_non_working_day)

# A Monday in September
happen(on_normal_trash_day, ymd("2019-09-09"))
#> [1] TRUE
happen(on_trash_day, ymd("2019-09-09"))
#> [1] TRUE

# Labor Day Monday should not be trash day
happen(on_normal_trash_day, ymd("2019-09-02"))
#> [1] TRUE
happen(on_trash_day, ymd("2019-09-02"))
#> [1] FALSE

# The day after Labor Day Monday is trash day
happen(on_normal_trash_day, ymd("2019-09-03"))
#> [1] FALSE
happen(on_trash_day, ymd("2019-09-03"))
#> [1] TRUE

# Say that a trash inspector always comes the day after trash day, whatever
# day that happens to be.

on_inspection_day <-
  on_trash_day %>%
  roll_by(1, "day")

# Inspector comes on a Tuesday in September
happen(on_inspection_day, ymd("2019-09-10"))
#> [1] TRUE

# Inspector doesn't come on that Wednesday
happen(on_inspection_day, ymd("2019-09-11"))
#> [1] FALSE

# Inspector doesn't come on the Tuesday after Labor Day Monday
happen(on_inspection_day, ymd("2019-09-03"))
#> [1] FALSE

# Inspector does come on that Wednesday
happen(on_inspection_day, ymd("2019-09-04"))
#> [1] TRUE

Arguments

Value

Examples

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