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Date to ISO year (character)

Source: R/conversion_date_isoweek_isoyear.R
date_to_isoyear_c.Rd

Converts a date to its ISO 8601 week-based year, returned as a character string.

Usage

date_to_isoyear_c(x = lubridate::today())

# Default S3 method
date_to_isoyear_c(x)

# S3 method for class 'character'
date_to_isoyear_c(x = lubridate::today())

# S3 method for class 'Date'
date_to_isoyear_c(x = lubridate::today())

Arguments

x

A Date object, or a character string in the format 'yyyy-mm-dd'.

Value

ISO year as a character vector (e.g. "2021").

Details

The ISO 8601 week-based year is not always the same as the calendar year. ISO weeks run Monday to Sunday. Week 1 is the week that contains the first Thursday of the year. As a result, the first days of January can belong to the last ISO week of the previous year. The last days of December can belong to ISO week 1 of the following year. For example, 2021-01-01 is a Friday that falls in ISO week 53 of ISO year 2020.

See also

vignette("cstime", package = "cstime") and vignette("date_conversion", package = "cstime"), which both run this function.

Other date-to-character converters: date_to_calmonth_c(), date_to_calyear_c(), date_to_calyearmonth_c(), date_to_isoquarter_c(), date_to_isoweek_c(), date_to_isoyearquarter_c(), date_to_isoyearweek_c()

Examples

date_to_isoyear_c(as.Date("2021-08-11"))
#> [1] "2021"
date_to_isoyear_c("2021-01-01")
#> [1] "2020"