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Cyclical time helpers

Source: R/cyclical_time.R
cyclical_time_helpers.Rd

Helper functions for creating cyclical time representations. These functions create time objects that repeat within a larger time cycle, useful for identifying seasonal patterns or positions within a calendar period.

Usage

month_of_year(data, discrete = TRUE, calendar = time_calendar(data), ...)

day_of_year(data, discrete = TRUE, calendar = time_calendar(data), ...)

day_of_month(data, discrete = TRUE, calendar = time_calendar(data), ...)

day_of_week(data, discrete = TRUE, calendar = time_calendar(data), ...)

week_of_year(data, discrete = TRUE, calendar = time_calendar(data), ...)

Arguments

data

Another object to be coerced into the specified cyclical time.

discrete

If TRUE, the position within the cycle that data falls into is returned as an integer. If FALSE, a fractional position is returned (analagous to time using a continuous time model).

calendar

A calendar object specifying the calendar system to use.

...

Additional arguments for cyclical_time(), such as tz for timezones.

Gregorian cyclical time representations

  • month_of_year(): Represents the month position within a year (1-12). The chronon is one month, cycling within a year.

  • day_of_year(): Represents the day position within a year (1-365 or 1-366 for leap years). The chronon is one day, cycling within a year.

  • day_of_month(): Represents the day position within a month (1-28, 1-29, 1-30, or 1-31 depending on the month). The chronon is one day, cycling within a month.

ISO 8601 cyclical time representations

  • day_of_week(): Represents the day position within a week (1-7) using the ISO 8601 standard where weeks start on Monday.

  • week_of_year(): Represents the week position within a year (1-52 or 1-53) using the ISO 8601 week numbering system.

Custom cyclical time representations

You can create custom cyclical time representations using cyclical_time() with any of the supported time units (see calendar_gregorian and calendar_isoweek).

For example, to create a representation for day of the month:

day_of_month <- new_cyclical_time_fn(
  chronon = day(1L), cycle = month(1L),
  fallback_calendar = cal_gregorian
)

See also

cyclical_time() for creating custom cyclical time vectors, linear_time_helpers for linear time helper functions, new_cyclical_time_fn() for creating cyclical time helper functions

Examples


month_of_year(Sys.Date())
#> <mixtime[1]>
#> [1] Feb
day_of_year(Sys.Date())
#> <mixtime[1]>
#> [1] 55
day_of_week(Sys.Date())
#> <mixtime[1]>
#> [1] Tue
day_of_week(as.Date("2025-12-15") + 0:6)
#> <mixtime[7]>
#> [1] Mon Tue Wed Thu Fri Sat Sun