我有以下数据框：
structure(list(x = c(1, 1, 2, 2, 3, 3, 4, 4, 5, 5, 1, 2, 3, 3,
4, 4, 5), cat = c("type1", "type1", "type1", "type1", "type1",
"type1", "type1", "type1", "type1", "type1", "type2", "type2",
"type2", "type2", "type2", "type2", "type2"), y = c("a", "b",
"a", "b", "a", "b", "a", "b", "a", "b", "c", "c", "c", "d", "c",
"d", "c")), row.names = c(NA, 17L), .Names = c("x", "cat", "y"
), class = "data.frame")
我想得到这个输出：
library(dplyr)
inner_join(filter(df, cat == 'type1'), filter(df, cat == 'type2'), by = 'x')
x cat.x y.x cat.y y.y
1 1 type1 a type2 c
2 1 type1 b type2 c
3 2 type1 a type2 c
4 2 type1 b type2 c
5 3 type1 a type2 c
6 3 type1 a type2 d
7 3 type1 b type2 c
8 3 type1 b type2 d
9 4 type1 a type2 c
10 4 type1 a type2 d
11 4 type1 b type2 c
12 4 type1 b type2 d
13 5 type1 a type2 c
14 5 type1 b type2 c
虽然我得到了我想要的东西但我不喜欢复杂的步骤。我知道tidyr包的spread在这种情况下不起作用。有什么想法吗？