Expand a time series to future years — expand

Completes the year sequence for each group up to `max_year`, adding rows (filled with `NA`) for any missing years. Operates on any "long" intervention implementation data.frame (e.g. `site$interventions$itn$use`) that has one row per group per year.

Usage

expand_years(x, max_year, group_var)

Arguments

x: An intervention implementation data.frame (long format, one row per group per year).
max_year: Maximum year to expand to
group_var: Character vector of grouping (site) columns