小编use*_*618的帖子

假设我有一个这样的数据帧:

hand_id card_id card_name card_class
A       1       p          alpha
A       2       q          beta
A       3       r          theta
B       2       q          beta
B       3       r          theta
B       4       s          gamma
C       1       p          alpha
C       2       q          beta 

我想将card_id,card_name和card_class连接成每一级A,B,C的单行.所以结果看起来像这样:

hand_id  combo_1  combo_2  combo_3
A        1-2-3    p-q-r    alpha-beta-theta
B        2-3-4    q-r-s    beta-theta-gamma
....

我尝试使用group_by和mutate来做到这一点,但我似乎无法让它工作

    data <- read_csv('data.csv')
    byHand <- group_by(data, hand_id) %>%
      mutate(combo_1 = paste(card_id), 
             combo_2 = paste(card_name),
             combo_3 = paste(card_class))

谢谢您的帮助.