Convert between tbl_now and tsibble

A tsibble::tsibble() has a single time index and a key identifying each series. Nowcasting needs two time indices, so the conversion keeps both date columns: the index is the event date and the report date (plus any strata) becomes part of the key.

tbl_now_from_tsibble() converts a tbl_ts into a tbl_now. You must say which column is the report_date; event_date defaults to the tsibble's index (tsibble::index_var()).

tbl_now_to_tsibble() converts a tbl_now into a tbl_ts, using index ("event_date", the default, or "report_date") as the tsibble index and the other date plus the strata as the key. Linelist data is aggregated to count-incidence first (a tsibble requires unique index/key combinations). The covariates, the censoring indicator and any materialised temporal-effect columns (see compute_temporal_effects()) ride along as measurement columns.

Usage

tbl_now_from_tsibble(
  data,
  report_date,
  event_date = NULL,
  strata = NULL,
  ...,
  verbose = TRUE
)

tbl_now_to_tsibble(
  x,
  ...,
  index = c("event_date", "report_date"),
  verbose = TRUE
)

Arguments

data

A tbl_ts (tsibble).

report_date

Column name of the report date (required for from).

event_date

Column name of the event date (for from); defaults to the tsibble index.

strata

Optional character vector of strata columns (from). If NULL (default) the tsibble key columns other than the date columns are used.

...

Forwarded to as_tbl_now() (from) or tsibble::as_tsibble() (to).

verbose

Logical. Print the choices that were made.

x

A tbl_now object.

index

For to: which date becomes the tsibble index, "event_date" (default) or "report_date".

Value

A tbl_now (from) or a tbl_ts (to).

Examples

data(denguedat)
nowobj <- tbl_now(denguedat,
  event_date = "onset_week",
  report_date = "report_week", verbose = FALSE
)
# The tsibble is indexed by the event date; the report date is in the key.
ts   <- tbl_now_to_tsibble(nowobj, verbose = FALSE)
#> Warning: tsibble requires unique index/key rows; aggregating linelist to
#> "count-incidence" with `to_count()`.
back <- tbl_now_from_tsibble(ts, report_date = "report_week", verbose = FALSE)