Date, year, week conversion

Chi Zhang

2022-05-04

We create the following functions to make it easier to work with date and times in different formats.

For the input, we allow either a numeric (3) or string (“03”, “2020-03”).

For the output, the user need to specify whether numeric or string is required. Functions end with c returns a character output and n returns a double.

library(cstime)
#> cstime 2024.6.13
#> https://www.csids.no/cstime/
library(magrittr)

Which year/week is this date?

By default the functions returns the isoyear or isoweek of today.

date_to_isoyear_c()
#> [1] "2024"
date_to_isoyear_n()
#> [1] 2024
date_to_isoweek_c()
#> [1] "24"
date_to_isoweek_n()
#> [1] 24
# provide a date
date_to_isoyear_c('2021-01-01')
#> [1] "2020"
date_to_isoyear_n('2021-01-01')
#> [1] 2020
date_to_isoweek_c('2021-01-01')
#> [1] "53"
date_to_isoweek_n('2021-01-01')
#> [1] 53
date_to_isoyearweek_c('2021-08-11')
#> [1] "2021-32"

Get isoyear/isoweek from a isoyearweek string

isoyearweek_to_isoyear_c("2021-02")
#> [1] "2021"
isoyearweek_to_isoyear_n("2021-02")
#> [1] 2021
isoyearweek_to_isoweek_c("2021-02")
#> [1] "02"
isoyearweek_to_isoweek_n("2021-02")
#> [1] 2

A list of isoyearweek can be accessed in the following way.

yrwk_19_20 <- dates_by_isoyearweek[isoyear %in% c(2019, 2020)]
head(yrwk_19_20)
#>    isoyear isoyearweek        mon        tue        wed        thu        fri
#> 1:    2019     2019-01 2018-12-31 2019-01-01 2019-01-02 2019-01-03 2019-01-04
#> 2:    2019     2019-02 2019-01-07 2019-01-08 2019-01-09 2019-01-10 2019-01-11
#> 3:    2019     2019-03 2019-01-14 2019-01-15 2019-01-16 2019-01-17 2019-01-18
#> 4:    2019     2019-04 2019-01-21 2019-01-22 2019-01-23 2019-01-24 2019-01-25
#> 5:    2019     2019-05 2019-01-28 2019-01-29 2019-01-30 2019-01-31 2019-02-01
#> 6:    2019     2019-06 2019-02-04 2019-02-05 2019-02-06 2019-02-07 2019-02-08
#>           sat        sun                                               weekdays
#> 1: 2019-01-05 2019-01-06 2018-12-31,2019-01-01,2019-01-02,2019-01-03,2019-01-04
#> 2: 2019-01-12 2019-01-13 2019-01-07,2019-01-08,2019-01-09,2019-01-10,2019-01-11
#> 3: 2019-01-19 2019-01-20 2019-01-14,2019-01-15,2019-01-16,2019-01-17,2019-01-18
#> 4: 2019-01-26 2019-01-27 2019-01-21,2019-01-22,2019-01-23,2019-01-24,2019-01-25
#> 5: 2019-02-02 2019-02-03 2019-01-28,2019-01-29,2019-01-30,2019-01-31,2019-02-01
#> 6: 2019-02-09 2019-02-10 2019-02-04,2019-02-05,2019-02-06,2019-02-07,2019-02-08
#>                  weekend
#> 1: 2019-01-05,2019-01-06
#> 2: 2019-01-12,2019-01-13
#> 3: 2019-01-19,2019-01-20
#> 4: 2019-01-26,2019-01-27
#> 5: 2019-02-02,2019-02-03
#> 6: 2019-02-09,2019-02-10
#>                                                                     days
#> 1: 2018-12-31,2019-01-01,2019-01-02,2019-01-03,2019-01-04,2019-01-05,...
#> 2: 2019-01-07,2019-01-08,2019-01-09,2019-01-10,2019-01-11,2019-01-12,...
#> 3: 2019-01-14,2019-01-15,2019-01-16,2019-01-17,2019-01-18,2019-01-19,...
#> 4: 2019-01-21,2019-01-22,2019-01-23,2019-01-24,2019-01-25,2019-01-26,...
#> 5: 2019-01-28,2019-01-29,2019-01-30,2019-01-31,2019-02-01,2019-02-02,...
#> 6: 2019-02-04,2019-02-05,2019-02-06,2019-02-07,2019-02-08,2019-02-09,...