数据框R中字符元素的条件替换[重复]答案

【问题标题】：Conditional Replacement of character elements in data frame R [duplicate]数据框R中字符元素的条件替换[重复]
【发布时间】：2016-04-25 19:42:33
【问题描述】：

我的数据是这样的

win_loss_table<- data.frame(Player = c("A","B","C","D","E","A","C"),Status = c("A","C","D","Draw","E","C","D"))
> win_loss_table
  Player Status
1      A      A
2      B      C
3      C      D
4      D   Draw
5      E      E
6      A      C
7      C      D

转换后的表格应如下所示

desired_table <- data.frame(Player = c("A","B","C","D","E","A","C"), Status= c("Won","Lost","Lost","Draw","W0n","Lost","Lost"))
> desired_table
  Player Status
1      A    Won
2      B   Lost
3      C   Lost
4      D   Draw
5      E    Won
6      A   Lost
7      C   Lost

但是使用下面的代码我得到一个这样的数据框，这是不正确的

incorrect_table<- data.frame(Player = c("A","B","C","D","E","A","C"),Status=as.factor(ifelse(win_loss_table$Status == "Draw","Draw",ifelse(win_loss_table$Player %in% win_loss_table$Status,"Won","Lost"))))
>incorrect_table
  Player Status
1      A    Won
2      B   Lost
3      C    Won
4      D   Draw
5      E    Won
6      A    Won
7      C    Won

任何关于我哪里出错的帮助将不胜感激

【问题讨论】：

我认为问题出在：ifelse(win_loss_table$Player %in% win_loss_table$Status,"Won","Lost")，它不会将值与值进行比较，而是在第二个列表 win_loss_table$Status 中查看第一个列表 (win_loss_table$Player) 中的每个值。如答案所示，一个简单的== 就可以完成这项工作。

标签： r

【解决方案1】：

您真的不想在因子水平上胡闹。处理角色要容易得多。首先让我们将列强制转换为字符。

win_loss_table[] <- lapply(win_loss_table, as.character)

然后我们可以用向量子集确定赢/输，然后替换 Draw。

with(win_loss_table, {
    replace(c("Won", "Lost")[(Player != Status) + 1L], Status == "Draw", "Draw")
})
# [1] "Won"  "Lost" "Lost" "Draw" "Won"  "Lost" "Lost"

【讨论】：

【解决方案2】：

一种方法是使用嵌套的ifelse

as.factor(ifelse(as.character(win_loss_table$Player) == as.character(win_loss_table$Status), "Won",
   ifelse(as.character(win_loss_table$Status) == "Draw", "Draw", "Lost")))

#[1] Won  Lost Lost Draw Won  Lost Lost
#Levels: Draw Lost Won

data.frame(Player = c("A","B","C","D","E","A","C"), Status = factor(ifelse(as.character(win_loss_table$Player) == as.character(win_loss_table$Status), "Won",
                                                                       ifelse(as.character(win_loss_table$Status) == "Draw", "Draw", "Lost"))))

#  Player Status
#1      A    Won
#2      B   Lost
#3      C   Lost
#4      D   Draw
#5      E    Won
#6      A   Lost
#7      C   Lost

【讨论】：