recur_with_week_start {almanac}

Control the start of the week

Description

recur_with_week_start() controls the week day that represents the start of the week. This is important for rules that use recur_on_week_of_year().

The default day of the week to start on is Monday.

Usage

recur_with_week_start(x, day)

Arguments

x

⁠[rrule]⁠

A recurrence rule.

day

⁠[integer(1) / character(1)]⁠

Day of the week to start the week on. Must be an integer value in ⁠[1, 7]⁠, with 1 = Monday and 7 = Sunday. This is also allowed to be a full weekday string like "Tuesday", or an abbreviation like "Tues".

Value

An updated rrule.

Examples

# Weekly rules are a bit tricky because they are implemented to comply
# with ISO-8601 standards, which require that the first week of the year
# is when there are at least 4 days in that year, and the week starts on
# the week day specified by `recur_with_week_start()` (Monday by default).
on_first_week <- yearly() %>% recur_on_week_of_year(1)

# In 2017:
# - Look at dates 1-4
# - 2017-01-02 is a Monday, so start the first week here
alma_search("2017-01-01", "2017-01-25", on_first_week)

# In 2015:
# - Look at dates 1-4
# - None of these are Monday, so the start of the week is
#   in the previous year
# - Look at 2014 and find the last Monday, 2014-12-29. This is the start of
#   the first week in 2015.
alma_search("2014-12-25", "2015-01-25", on_first_week)

# Say we want the start of the week to be Sunday instead of Monday!

# In 2015:
# - Look at dates 1-4
# - 2015-01-04 is a Sunday, so start the first week here
on_first_week_sun <- yearly() %>%
  recur_on_week_of_year(1) %>%
  recur_with_week_start("Sunday")

alma_search("2014-12-25", "2015-01-25", on_first_week_sun)