R： 如何根据不同的数据帧为数据帧中的每个人提供相同的id号？

我有两个数据集，df和df2。这是两个非常大且混乱的数据帧的过度简化版本。

在最初的df中，我通过按腰带和体重分组为每个人创建了一个唯一的id。我希望每个人在df中都有相同的身份证号码，以便给df2中的同一个人。它们需要具有相同的名称，并应按皮带和重量分组。注意，df2中有一些人不在df中。

简化的df如下所示

     belt     weight rank id        name
1  purple open class    1 55  Tom Cruise
2   black    rooster    2 79 Emma Watson
3    blue    feather    3 63    John Doe
4    blue    feather    4 63    John Doe
5  purple open class    5 55  Tom Cruise
6   brown      heavy    6  3  James Bond
7  purple open class    7 55  Tom Cruise
8  purple      heavy    8 61  Tom Cruise
9   black open class    9 70    Jane Doe
10 purple      heavy   10 61  Tom Cruise

第二个数据帧看起来像这样。一个在df2，但不在df的人应该收到一个NA作为他们的id。注意，id必须由腰带和体重给出，因为有些人根据他们所参加的体重组别而有不同的分数

    belt2    weight2 rank2        name points
1  purple open class     1  Tom Cruise    100
2   black    rooster     2 Emma Watson     30
3    blue    feather     3    John Doe     50
4    blue    feather     4    John Doe     50
5  purple open class     5  Tom Cruise    100
6   brown      heavy     6  James Bond    200
7   black    rooster     7    Jon Snow     92
8  purple      heavy     8  Tom Cruise     77
9   black open class     9    Jane Doe     88
10 purple      heavy    10  Tom Cruise     77

这是我希望df2的样子：

    belt2    weight2 rank2 id           name points
1  purple open class     1 55     Tom Cruise    100
2   black    rooster     2 79    Emma Watson     30
3    blue    feather     3 63       John Doe     50
4    blue    feather     4 63       John Doe     50
5  purple open class     5 55     Tom Cruise    100
6   brown      heavy     6  3     James Bond    200
7   black    rooster     7 NA       Jon Snow     92
8  purple      heavy     8 61     Tom Cruise     77
9   black open class     9 70       Jane Doe     88
10 purple      heavy    10 61     Tom Cruise     77

基本上，我希望df2中的id号与df中的id编号匹配。如果不匹配，请填写NA。

# df
belt <- c("purple", "black", "blue", "blue", "purple", "brown", "purple", "purple", "black", "purple")
weight <- c("open class", "rooster", "feather", "feather", "open class", "heavy", "open class", "heavy", "open class", "heavy")
rank <- 1:10
id <- c(55, 79, 63, 63, 55, 3, 55, 61, 70, 61)
names <- c("Tom Cruise", "Emma Watson", "John Doe", "John Doe", "Tom Cruise", "James Bond", "Tom Cruise", "Tom Cruise", "Jane Doe", "Tom Cruise")
(df <- data.frame(belt, weight, rank, id, name = names))

#df2
belt2 <- c("purple", "black", "blue", "blue", "purple", "brown", "black", "purple", "black", "purple")
weight2 <- c("open class", "rooster", "feather", "feather", "open class", "heavy", "rooster", "heavy", "open class", "heavy")
rank2 <- 1:10
names2 <- c("Tom Cruise", "Emma Watson", "John Doe", "John Doe", "Tom Cruise", "James Bond", "Jon Snow", "Tom Cruise", "Jane Doe", "Tom Cruise")
points <- c(100, 30, 50, 50, 100, 200, 92, 77, 88, 77)
(df2 <- data.frame(belt2, weight2, rank2, name = names2, points))