Date to season week (numeric)

Maps a date to its position within the surveillance season, where season week 1 corresponds to ISO week 35.

Usage

date_to_seasonweek_n(x)

Arguments

x

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

Value

Season week as a numeric vector.

Details

The date is first converted to an ISO yearweek with date_to_isoyearweek_c() and then to a season week with isoyearweek_to_seasonweek_n(). As with isoweek_to_seasonweek_n(), ISO week 53 maps to the half-step season week 18.5.

See also

date_to_season_c() for the season itself, and isoyearweek_to_seasonweek_n() to start from an ISO yearweek instead. vignette("season", package = "cstime") for worked season week conversions. No vignette runs this function.

Examples

date_to_seasonweek_n(c("2021-01-01", "2021-12-01"))
#> [1] 18.5 14.0
date_to_seasonweek_n(as.Date("2021-09-01"))
#> [1] 1