Time conversion

Chi Zhang

2022-02-22

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(fhiplot)
#> fhiplot 2022.2.22 https://folkehelseinstituttet.github.io/fhiplot

Which year/week is it?

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

isoyear_c()
#> [1] "2022"
isoyear_n()
#> [1] 2022
isoweek_c()
#> [1] "08"
isoweek_n()
#> [1] 8

# provide a date
isoyear_c('2021-01-01')
#> [1] "2020"
isoyear_n('2021-01-01')
#> [1] 2020
isoweek_c('2021-01-01')
#> [1] "53"
isoweek_n('2021-01-01')
#> [1] 53

Get year/week from a isoyearweek string

isoyearweek_to_year_c("2021-02")
#> [1] "2021"
isoyearweek_to_year_n("2021-02")
#> [1] 2021
isoyearweek_to_week_c("2021-02")
#> [1] "02"
isoyearweek_to_week_n("2021-02")
#> [1] 2

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

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