Split a gtsummary table

split_gtsummary_tbl.R

split_gtsummary_tbl <- function(x, .split_after) {
  # get row index where splits occur
  df_index <-
    .split_after %>% 
    purrr::map_int(~x$table_body$variable %in% .x %>%
                 which() %>%
                 max()) %>%
    {union(., nrow(x$table_body))} %>%
    sort() %>%
    unique() %>%
    {tibble::tibble(..index.. = .)} %>%
    mutate(..group.. = dplyr::row_number())
  
  # nest `x$table_body` within each group
  nested_table_body <-
    x$table_body %>%
    dplyr::mutate(..index.. = dplyr::row_number()) %>%
    dplyr::left_join(df_index, by = "..index..") %>%
    tidyr::fill(..group.., .direction = "up") %>%
    tidyr::nest(data = -..group..)
  
  # return gtsummary tbl list
  purrr::map(
    seq_len(nrow(nested_table_body)),
    function(..group..) {
      x$table_body <- nested_table_body$data[[..group..]]
      x
    }
  )
}

tt <- 
  trial %>%
  tbl_summary(by = trt) %>%
  add_p()

split_gtsummary_tbl(tt, .split_after = c("marker", "grade"))