ISO calendar dates

Create an ISO 8601 date object. Weeks are defined as starting on Mondays. Week 1 is 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.

Usage

iso_date(year = integer(), week = integer(), day = integer())

as_iso(date, ...)

Arguments

year

A numeric vector of years

week

A numeric vector of weeks

day

A numeric vector of days

date

Vector of dates on some calendar

...

Additional arguments not currently used

Value

An iso vector object

Details

More flexible week numbering is possible using Gregorian dates with week_of_year().

See also

week_of_year()

Examples

iso_date(2025, 23, 2:4)
#> <iso[3]>
#> [1] 2025-23-02 2025-23-03 2025-23-04
as_gregorian(iso_date(2025, 23, 2:4))
#> <gregorian[3]>
#> [1] 2025-Jun-03 2025-Jun-04 2025-Jun-05
as_iso(gregorian_date(2025, 1, 1:31))
#> <iso[31]>
#>  [1] 2025-01-03 2025-01-04 2025-01-05 2025-01-06 2025-01-07 2025-02-01
#>  [7] 2025-02-02 2025-02-03 2025-02-04 2025-02-05 2025-02-06 2025-02-07
#> [13] 2025-03-01 2025-03-02 2025-03-03 2025-03-04 2025-03-05 2025-03-06
#> [19] 2025-03-07 2025-04-01 2025-04-02 2025-04-03 2025-04-04 2025-04-05
#> [25] 2025-04-06 2025-04-07 2025-05-01 2025-05-02 2025-05-03 2025-05-04
#> [31] 2025-05-05
as_iso("2016-01-01")
#> <iso[1]>
#> [1] 2015-53-05
as_iso(Sys.Date())
#> <iso[1]>
#> [1] 2025-22-02
tibble::tibble(
  date = seq(as.Date("2025-01-01"), as.Date("2025-12-31"), by = "day"),
  iso = as_iso(date)
)
#> # A tibble: 365 × 2
#>    date              iso
#>    <date>          <iso>
#>  1 2025-01-01 2025-01-03
#>  2 2025-01-02 2025-01-04
#>  3 2025-01-03 2025-01-05
#>  4 2025-01-04 2025-01-06
#>  5 2025-01-05 2025-01-07
#>  6 2025-01-06 2025-02-01
#>  7 2025-01-07 2025-02-02
#>  8 2025-01-08 2025-02-03
#>  9 2025-01-09 2025-02-04
#> 10 2025-01-10 2025-02-05
#> # ℹ 355 more rows