R 根据引用在数据框中添加列

我有两个具有不同类型数据(data 1 -3)的array.两者都涉及相同的参与者("person 1"等). df1包含列group.我想把这一栏加到df2栏，根据ID栏(例如，person3永远属于group1).请注意，在两个嵌套框中，每person行的行数(=唯一观测值)不相等.

这是我的输入:

ID <- c("person1", "person1", "person2", "person3", "person3", "person3", "person4")
data1 <- c(1:7)
data2 <- c(6:12)
group <- c("group1", "group1", "group2", "group1", "group1", "group1", "group2")
df1 <- data.frame(ID, data1, data2, group)

ID <- c("person1", "person2", "person2", "person3", "person3", "person4", "person4")
data3 <- c(7:13)
df2 <- data.frame(ID, data3)

> df1
       ID data1 data2  group
1 person1     1     6 group1
2 person1     2     7 group1
3 person2     3     8 group2
4 person3     4     9 group1
5 person3     5    10 group1
6 person3     6    11 group1
7 person4     7    12 group2

> df2
       ID data3
1 person1     7
2 person2     8
3 person2     9
4 person3    10
5 person3    11
6 person4    12
7 person4    13

这是所需的输出:

ID <- c("person1", "person2", "person2", "person3", "person3", "person4", "person4")
data3 <- c(7:13)
group <- c("group1", "group2", "group2", "group1", "group1", "group2", "group2")
df2final <- data.frame(ID, data3, group)

> df2final
       ID data3  group
1 person1     7 group1
2 person2     8 group2
3 person2     9 group2
4 person3    10 group1
5 person3    11 group1
6 person4    12 group2
7 person4    13 group2

谢谢大家！