R中的ifelse语句不起作用-列结果不正确

Question

I have a df:

Year | Stage | Home.Team.Name | Home.Team.Goals | Away.Team.Name | Away.Team.Goals

1998 | Group A| Brazil..................| 2............................ | Scotland............... | 1

and so on.

What I'm trying to do is create a new column based off the result of each game. So the winners name appears in a new column. The code I currently have is:

RecentWorldCups$Game.Winner <- ifelse(RecentWorldCups$Home.Team.Goals>RecentWorldCups$Away.Team.Goals, RecentWorldCups$Home.Team.Name,
                                      ifelse(RecentWorldCups$Away.Team.Goals>RecentWorldCups$Home.Team.Goals, RecentWorldCups$Away.Team.Name,
                                             "Draw"))

The result of this is that it gives me a number (perhaps a factor number?) instead of the name of the team.

Anyone able to help? Cheers

Answer 1

You need to extract the character level value from your factor columns. Try this:

df <- RecentWorldCups     # for readability of your code

df$Game.Winner <- ifelse(df$Home.Team.Goals > df$Away.Team.Goals,
   levels(df$Home.Team.Name)[df$Home.Team.Name],
   ifelse(df$Away.Team.Goals > df$Home.Team.Goals,
       levels(df$Away.Team.Name)[df$Away.Team.Name],
       "Draw")
)

If you find it cumbersome to do these factor conversions, then one workaround would be to create your data frame with all strings set to not be factors, eg something like this:

RecentWorldCups <- data.frame(Home.Team.Goals=c(...), ..., stringsAsFactors=FALSE)