gregorian-parts: Compute granularities from dates

In calcal: Calendrical Calculations

Compute granularities from dates

Description

Compute days, weeks, or months from a vector of dates. These work for Gregorian dates, and for some other calendars where it makes sense. In particular, day_of_week has been implemented for many calendars that contain the concept of a week. Similarly, day_of_month, day_of_year and days_remaining will work for several calendars.

Usage

day_of_week(date, ...)

day_of_month(date)

day_of_year(date)

days_remaining(date)

week_of_month(date, first_day = "Monday")

week_of_year(date, first_day = "Monday")

month_of_year(date)

year(date)

Arguments

date	A vector of dates
...	Other arguments used for specific calendars
first_day	Character denoting first day of the week. Default is "Monday"

Details

week_of_year() returns the ISO 8601 week number with first_day as Monday. Under this standard, week 1 of a year is defined as the first week with at least 4 days in the year; equivalently, it is the week containing 4 January. There is no week 0; instead week 1 of a year may begin in the previous calendar year.

week_of_month() is defined analogously where week 1 of a month is the first week with at least 4 days in the month; equivalently, it is the week containing the 4th day of the month. There is no week 0; instead week 1 of a month may begin in the previous calendar month.

days_remaining() returns the number of days remaining in the year.

Other functions should be self-explanatory.

Value

A vector of numerical values for the requested granularity. In the case of day_of_week(), it returns a character vector of the name of the day of the week, or a numeric vector if numeric = TRUE is specified.

Examples

april2025 <- gregorian_date(2025, 4, 1:30)
day_of_week(april2025)
day_of_month(april2025)
day_of_year(april2025)
days_remaining(april2025)
week_of_month(april2025)
week_of_year(april2025)
month_of_year(april2025)

calcal documentation built on Feb. 25, 2026, 9:07 a.m.