我尝试id3根据两个变量(id1,id2)找到"group"():
df = data.frame(id1 = c(1,1,2,2,3,3,4,4,5,5),
id2 = c('a','b','a','c','c','d','x','y','y','z'),
id3 = c(rep('group1',6), rep('group2',4)))
id1 id2 id3
1 1 a group1
2 1 b group1
3 2 a group1
4 2 c group1
5 3 c group1
6 3 d group1
7 4 x group2
8 4 y group2
9 5 y group2
10 5 z group2
例如 id1=1关系到a和b的id2.但id1=2也与之相关,a因此两者都属于一个群体(id3=group1).但既然id1=2和id1=3 …
r ×1