如果您想为类似的目标实现简单的实现,可以尝试listParts
使用package partitions
,例如,
> x <- 4
> partitions::listParts(x)
[[1]]
[1] (1,2,3,4)
[[2]]
[1] (1,2,4)(3)
[[3]]
[1] (1,2,3)(4)
[[4]]
[1] (1,3,4)(2)
[[5]]
[1] (2,3,4)(1)
[[6]]
[1] (1,4)(2,3)
[[7]]
[1] (1,2)(3,4)
[[8]]
[1] (1,3)(2,4)
[[9]]
[1] (1,4)(2)(3)
[[10]]
[1] (1,2)(3)(4)
[[11]]
[1] (1,3)(2)(4)
[[12]]
[1] (2,4)(1)(3)
[[13]]
[1] (2,3)(1)(4)
[[14]]
[1] (3,4)(1)(2)
[[15]]
[1] (1)(2)(3)(4)
其中x
是集合中元素的数量,所有分区均表示元素的索引。
如果要选择分区数,下面是一个用户功能,可能会有所帮助
f <- function(x, n) {
res <- listParts(x)
subset(res, lengths(res) == n)
}
这样
> f(x, 2)
[[1]]
[1] (1,2,4)(3)
[[2]]
[1] (1,2,3)(4)
[[3]]
[1] (1,3,4)(2)
[[4]]
[1] (2,3,4)(1)
[[5]]
[1] (1,4)(2,3)
[[6]]
[1] (1,2)(3,4)
[[7]]
[1] (1,3)(2,4)
> f(x, 3)
[[1]]
[1] (1,4)(2)(3)
[[2]]
[1] (1,2)(3)(4)
[[3]]
[1] (1,3)(2)(4)
[[4]]
[1] (2,4)(1)(3)
[[5]]
[1] (2,3)(1)(4)
[[6]]
[1] (3,4)(1)(2)
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