npermutations {arrangements}

Number of permutations

Description

Number of permutations

Usage

npermutations(x = NULL, k = NULL, n = NULL, v = NULL,
  freq = NULL, replace = FALSE, bigz = FALSE)

Arguments

x

an integer or a vector, will be treated as n if integer; otherwise, will be treated as v. Should not be specified together with n and v.

k

an integer, the number of items drawn, defaults to n if freq is NULL else sum(freq)

n

an integer, the total number of items, its value may be implicitly deduced from length(v) or length(freq)

v

a vector to be drawn, defaults to 1:n.

freq

an integer vector of item repeat frequencies

replace

an logical to draw items with replacement

bigz

an logical to use gmp::bigz

See Also

permutations for generating all permutations and ipermutations for iterating permutations

Examples

npermutations(7)
npermutations(LETTERS[1:5])
npermutations(5, 2)
npermutations(LETTERS, k = 5)

# integer overflow
## Not run: npermutations(14, 10)
npermutations(14, 10, bigz = TRUE)

# number of permutations of `c("a", "b", "b")`
# they are `c("a", "b")`, `c("b", "b")` and `c("b", "b")`
npermutations(k = 2, freq = c(1, 2))

# zero sized partitions
npermutations(0)
npermutations(5, 0)
npermutations(5, 6)
npermutations(0, 1)
npermutations(0, 0)