isubset: Subset Iterator

In combiter: Combinatorics Iterators

Description

Create an iterator for all subsets of integers 1 through n.

Usage

isubset(n)

isubsetv(values)

Arguments

n	positive integer
values	iterable (subsettable by [)

Details

• isubset iterates through integer vectors

• isubsetv iterates through general values

Value

iterator object

Examples

x <- isubset(3)
ct <- 0
while (hasNext(x))
{
  ct <- ct + 1
  i <- nextElem(x)
  cat(sprintf("%3d : %s\n", ct, paste0(i, collapse = " ")))
}

as.list(isubsetv(letters[1:4]))

Example output

  1 : 
  2 : 1
  3 : 2
  4 : 3
  5 : 1 2
  6 : 1 3
  7 : 2 3
  8 : 1 2 3
[[1]]
character(0)

[[2]]
[1] "a"

[[3]]
[1] "b"

[[4]]
[1] "c"

[[5]]
[1] "d"

[[6]]
[1] "a" "b"

[[7]]
[1] "a" "c"

[[8]]
[1] "a" "d"

[[9]]
[1] "b" "c"

[[10]]
[1] "b" "d"

[[11]]
[1] "c" "d"

[[12]]
[1] "a" "b" "c"

[[13]]
[1] "a" "b" "d"

[[14]]
[1] "a" "c" "d"

[[15]]
[1] "b" "c" "d"

[[16]]
[1] "a" "b" "c" "d"

combiter documentation built on May 2, 2019, 7:24 a.m.