arrangements (version 1.1.7)

permutations: Permutations generator

Description

This function generates all the permutations of selecting k items from n items. The results are in lexicographical order.

Usage

permutations(x = NULL, k = n, n = NULL, v = NULL, freq = NULL,
  replace = FALSE, layout = NULL, nitem = -1L, skip = NULL,
  index = NULL, nsample = NULL, drop = NULL)

Arguments

x

an integer or a vector, will be treated as n if integer; otherwise, will be treated as v

k

an integer, the number of items drawn

n

an integer, the total number of items, its actual value may be determined by other variables

v

a vector to be drawn

freq

an integer vector of item repeat frequencies

replace

an logical to draw items with replacement

layout

if "row", "column" or "list" is specified, the returned value would be a "row-major" matrix, a "column-major" matrix or a list respectively

nitem

number of permutations required, usually used with skip

skip

the number of permutations skipped

index

a vector of indices of the desired permutations

nsample

sampling random permutations

drop

vectorize a matrix or unlist a list

See Also

ipermutations for iterating permutations and npermutations to calculate number of permutations

Examples

# NOT RUN {
permutations(3)
permutations(LETTERS[1:3])

# choose 2 from 4
permutations(4, 2)
permutations(LETTERS[1:3], k = 2)

# multiset with frequencies c(2, 3)
permutations(k = 3, freq = c(2, 3))

# with replacement
permutations(4, 2, replace = TRUE)

# column major
permutations(3, layout = "column")
permutations(4, 2, layout = "column")

# list output
permutations(3, layout = "list")
permutations(4, 2, layout = "list")

# specifc range of permutations
permutations(4, 2, nitem = 2, skip = 3)

# specific permutations
permutations(4, 2, index = c(3, 5))

# random permutations
permutations(4, 2, nsample = 3)

# zero sized permutations
dim(permutations(0))
dim(permutations(5, 0))
dim(permutations(5, 6))
dim(permutations(0, 0))
dim(permutations(0, 1))

# }