Add next row's value to a list and then repeat adding row after row-CodePudding

I am running this code to create the DF included in the picture below:

library(tidyverse)
library(espnscrapeR)

steelers_data <- espnscrapeR::get_nfl_pbp(401326308) %>%
  group_by(drive_id) %>%
  janitor::clean_names() %>%
  dplyr::rename(
    posteam = pos_team_abb,
    qtr = drive_start_qtr,
    desc = play_desc) %>%
  select(game_id, drive_id, posteam, play_id, play_type, yards_gained, desc,
        logo, qtr, drive_result, home_team_abb, away_team_abb, home_wp) %>%
  mutate(home_wp = dplyr::lag(home_wp, 1)) %>%
  mutate(away_wp = 1.00 - home_wp) %>%
  filter(posteam == "PIT") %>%
  filter(!play_type %in% c("Kickoff", "End Period", "End of Half", "Timeout", "Kickoff Return (Offense)", "End of Game"))

##testing
testing <- steelers_data %>%
  filter(drive_id == "4013263082") %>%
  group_by(play_id) %>%
  summarize(wp_data = list(away_wp), .groups = "drop")

However, I would like to add the next row's wp_data to the prior. My desired output is this:

Any help is greatly appreciated.

CodePudding user response：

Use purrr::accumulate:

library(tidyverse)
data.frame(A = 1:10) %>% 
  mutate(A2 = purrr::accumulate(A, c))

or Reduce:

df <- data.frame(A = 1:10)
df$A2 <- Reduce(c, df$A, accumulate = T)

output

    A                            A2
1   1                             1
2   2                          1, 2
3   3                       1, 2, 3
4   4                    1, 2, 3, 4
5   5                 1, 2, 3, 4, 5
6   6              1, 2, 3, 4, 5, 6
7   7           1, 2, 3, 4, 5, 6, 7
8   8        1, 2, 3, 4, 5, 6, 7, 8
9   9     1, 2, 3, 4, 5, 6, 7, 8, 9
10 10 1, 2, 3, 4, 5, 6, 7, 8, 9, 10