Tidyverse:group_by、arrange和lag跨列

Question

我正在研究一个体育项目的投影模型，我需要了解某支球队最近的比赛：

< li >他们的下一个对手是谁？(已解决) < li >他们的下一个对手是什么时候？

可以在下面使用的reprex。以第1行为例，我需要理解“a”的下一个对手“e”的最近一场比赛是game_id_3。

game_id_ <- c(1, 1, 2, 2, 3, 3, 4, 4, 5, 5, 6, 6)

game_date_ <- c(rep("2021-01-29", 6), rep("2021-01-30", 6))

team_ <- c("a", "b", "c", "d", "e", "f", "b", "c", "d", "f", "e", "a")

opp_ <- c("b", "a", "d", "c", "f", "e", "c", "b", "f", "d", "a", "e")

df <- data.frame(game_id_, game_date_, team_, opp_)

#Next opponent
df <- df %>% 
  arrange(game_date_, game_id_, team_) %>% 
  group_by(team_) %>% 
  mutate(next_opp = lead(opp_, n = 1L))

如果我能提供更多细节，请告诉我。

Answer 1

我们可以使用匹配返回对应的game_id_

library(dplyr)
df %>%
   arrange(game_date_, game_id_, team_) %>%
   group_by(team_) %>%
   mutate(next_opp = lead(opp_, n = 1L)) %>%
   ungroup %>%
   mutate(last_time = game_id_[match(next_opp, opp_)])