Extract header N from a tplyr2 build result — tplyr_header

Returns the population-based header N values that were computed during tplyr_build(). Only available when population data was provided.

Usage

tplyr_header_n(result)

Arguments

result: A data.frame produced by tplyr_build()

Value

A data.frame with column variable levels and their N values, or NULL if no population data was used.

Examples

spec <- tplyr_spec(
  cols = "TRTA",
  pop_data = pop_data(cols = c("TRTA" = "TRT01P")),
  layers = tplyr_layers(group_count("AEBODSYS"))
)
built <- tplyr_build(spec, tplyr_adae, pop_data = tplyr_adsl)
tplyr_header_n(built)
#>                   TRTA .n
#> 1              Placebo 86
#> 2 Xanomeline High Dose 84
#> 3  Xanomeline Low Dose 84

# NULL when the build had no population data to draw an N from
no_pop <- tplyr_build(
  tplyr_spec(cols = "TRT01P", layers = tplyr_layers(group_count("SEX"))),
  tplyr_adsl
)
tplyr_header_n(no_pop)
#> NULL