加入/合併兩列數據幀

Question

說我有這個數據裏面，

(df <- data.frame(col1 = c('My','Your','His','Thir'), col2 = c('Cat','Dog','Fish','Dog'))) 

    col1 col2 
1 My Cat 
2 Your Dog 
3 His Fish 
4 Thir Dog 

，我想列組合在一起這樣

`some magic` 

    col1 col2  col3 
1 My Cat My Cat 
2 Your Dog Your Dog 
3 His Fish His Fish 
4 Thir Dog Thir Dog 

我該怎麼辦？甚至用逗號（，）這樣，

`some magic` 

    col1 col2  col3 
1 My Cat My, Cat 
2 Your Dog Your, Dog 
3 His Fish His, Fish 
4 Thir Dog Thir, Dog 

Answer 1

df$col3 <- paste(df$col1, df$col2, sep=",")。您也可以使用sprintf和paste0函數。

df$col3 <- paste(df$col1, df$col2, sep=",") # comma separator 
df$col3 <- paste0(df$col1, df$col2) # for no separator 

Answer 2

如果你想給他們留下的兩個列表，（不是字符串串聯兩個），那麼下面的工作以及

within(df, col3 <- Map(list, as.character(col1),as.character(col2))) 

    col1 col2  col3 
1 My Cat My, Cat 
2 Your Dog Your, Dog 
3 His Fish His, Fish 
4 Thir Dog Thir, Dog 

Map是mapply(..., SIMPLIFY = FALSE)