ISO week to season week (numeric)

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

Usage

isoweek_to_seasonweek_n(x)

# Default S3 method
isoweek_to_seasonweek_n(x)

# S3 method for class 'character'
isoweek_to_seasonweek_n(x)

# S3 method for class 'numeric'
isoweek_to_seasonweek_n(x)

Arguments

x

ISO week as a number between 1 and 53.

Value

Season week as a numeric vector (ISO week 53 returns 18.5).

Details

Surveillance seasons start at ISO week 35, so ISO week 35 is season week 1. ISO week 36 is season week 2, and the numbering continues across the new year. ISO week 53 occurs only in long ISO years. It maps to the half-step season week 18.5, so that the surrounding weeks keep consistent numbering.

See also

seasonweek_to_isoweek_n() and seasonweek_to_isoweek_c() convert back. They return different classes from each other, so they are not a family. vignette("cstime", package = "cstime") and vignette("season", package = "cstime"), which both run this function.

Examples

isoweek_to_seasonweek_n(35)
#> [1] 1
isoweek_to_seasonweek_n(c(31, 53))
#> [1] 49.0 18.5