聚合滚动平均值与 R 中的条件语句

Question

我有一个遵循以下格式的数据框。

 match  team1 team2 winningTeam
 1      A     D     A
 2      B     E     E
 3      C     F     C
 4      D     C     C
 5      E     B     B
 6      F     A     A
 7      A     D     D
 8      D     A     A

我想做的是创建变量来计算 1 队和 2 队在最后 x 场比赛中的状态。例如，我想创建一个名为 team1_form_last3_matches 的变量，对于第 8 场比赛，该变量将为 0.33（因为他们赢得了最后 3 场比赛中的 1 场），并且还会有一个名为 team2_form_last3_matches 的变量，它将是第 8 场比赛 0.66（因为他们赢得了最近 3 场比赛中的 2 场）。理想情况下，我希望能够指定在计算 teamx_form_lasty 变量和那些要自动创建的变量。我尝试了很多使用 dplyr、zoo 滚动均值函数和大量嵌套 for / if 语句的方法。但是，我还没有完全破解它，当然也不是以一种优雅的方式。我觉得我缺少针对这个一般问题的简单解决方案。任何帮助将不胜感激！

干杯，

杰克

Answer 1

怎么样：

dat <- data.frame(match = c(1:8), team1 = c("A","B","C","D","E","F","A","D"), team2 = c("D","E","F","C","B","A","D","A"), winningTeam = c("A","E","C","C","B","A","D","A"))
  match team1 team2 winningTeam
1     1     A     D           A
2     2     B     E           E
3     3     C     F           C
4     4     D     C           C
5     5     E     B           B
6     6     F     A           A
7     7     A     D           D
8     8     D     A           A

Allteams <- c("A","B","C","D","E","F")

# A vectorized function for you to use to do as you ask:
teamX_form_lastY <- function(teams, games, dat){
  sapply(teams, function(x) {
    games_info <- rowSums(dat[,c("team1","team2")] == x) + (dat[,"winningTeam"] == x)
    lookup <- ifelse(rev(games_info[games_info != 0])==2,1,0)
    games_won <- sum(lookup[1:games])
    if(length(lookup) < games) warning(paste("maximum games for team",x,"should be",length(lookup)))
    games_won/games
  })
}

teamX_form_lastY("A", 4, dat)
A 
0.75 

# Has a warning for the number of games you should be using
teamX_form_lastY("A", 5, dat)
A 
NA 
Warning message:
  In FUN(X[[i]], ...) : maximum games for team A should be 4

# vectorized input
teamX_form_lastY(teams = c("A","B"), games = 2, dat = dat)
A   B 
0.5 0.5 

# so you ca do all teams
teamX_form_lastY(teams = Allteams, 2, dat)
A   B   C   D   E   F 
0.5 0.5 1.0 0.5 0.5 0.0

Answer 2

这适用于 t1l3，您需要为 t2 复制它。

dat <- data.frame(match = c(1:8), team1 = c("A","B","C","D","E","F","A","D"), team2 = c("D","E","F","C","B","A","D","A"), winningTeam = c("A","E","C","C","B","A","D","A"),stringsAsFactors = FALSE)

dat$t1l3 <- c(NA,sapply(2:nrow(dat),function(i) {
  df <- dat[1:(i-1),] #just previous games, i.e. excludes current game
  df <- df[df$team1==dat$team1[i] | df$team2==dat$team1[i],] #just those containing T1
  df <- tail(df,3) #just the last three (or fewer if there aren't three previous games)
  return(sum(df$winningTeam==dat$team1[i])/nrow(df)) #total wins/total games (up to three)
}))

聚合滚动平均值与 R 中的条件语句

Aggregated rolling average with a conditional statement in R

r

moving-average

zoo

dplyr