We need to map "dates" onto dust::dust's concept of model
"step" and we do this by mapping a date such as 2020-03-02 into
the number of days into 2020 (62 here, with the 1st of January
being day 1). We call this integer number a "sircovid date".
sircovid_date(date)
sircovid_date_as_date(date)
as_sircovid_date(date)
as_date(date)A Date object, or something that can be converted to one, or a "sircovid date"; see Details
An integer, being the number of days into 2020
There are several related functions here
sircovid_date converts its argument into an R Date object,
then applies this tranformation. If the argument is not a Date
object or a string representing one, an error will be thrown.
sircovid_date_to_date does the reverse conversion to
sircovid_date, converting an integer sircovid date into an R
Date
as_sircovid_date does the same conversion as sircovid_date
but will assume that an integer already represents a sircovid
date and will return it unmodified rather than erroring.
as_date does a string to date conversion, using as.Date()
but requiring the dates are in ISO 8601 (YYYY-MM-DD) format (it
is a helper that avoids conversion to NA, instead throwing an
error)
# Convert dates into sircovid dates:
sircovid::sircovid_date("2020-01-01")
#> [1] 1
sircovid::sircovid_date(c("2020-03-01", "2020-10-01"))
#> [1] 61 275
# Reverse the conversion:
sircovid::sircovid_date_as_date(1)
#> [1] "2020-01-01"
sircovid::sircovid_date_as_date(c(61, 275))
#> [1] "2020-03-01" "2020-10-01"
# Double conversion not possible with sircovid_date...
try(sircovid::sircovid_date(61))
#> Error in as_date(date) : Expected ISO dates or R dates - please convert
# ...but allowed with as_sircovid_date
sircovid::as_sircovid_date(61)
#> [1] 61
# Strict date conversion with as_date
sircovid::as_date("2020-03-01")
#> [1] "2020-03-01"
try(sircovid::as_date("03-01-2020"))
#> Error in sircovid::as_date("03-01-2020") :
#> Expected ISO dates or R dates - please convert