Combinations {arrangements} | R Documentation |
This function returns a Combinations iterator for iterating
combinations of k
items from n
items. The iterator allows users to fetch the next
combination(s) via the getnext()
method.
Combinations icombinations(x = NULL, k = NULL, n = NULL, v = NULL, freq = NULL, replace = FALSE, skip = NULL)
x |
an integer or a vector, will be treated as |
k |
an integer, the number of items drawn, defaults to |
n |
an integer, the total number of items, its value may be implicitly deduced from |
v |
a vector to be drawn, defaults to |
freq |
an integer vector of item repeat frequencies |
replace |
an logical to draw items with replacement |
skip |
the number of combinations skipped |
An object of class R6ClassGenerator
of length 25.
The Combinations
class can be initialized by using the convenient wrapper icombinations
or
Combinations$new(n, k, v = NULL, freq = NULL, replace = FALSE)
getnext(d = 1L, layout = NULL, drop = NULL) collect(layout = "row") reset()
number of fetched arrangements
if "row", "column" or "list" is specified, the returned value would be a "row-major" matrix, a "column-major" matrix or a list respectively
vectorize a matrix or unlist a list
combinations for generating all combinations and ncombinations to calculate number of combinations
icomb <- icombinations(5, 2) icomb$getnext() icomb$getnext(2) icomb$getnext(layout = "column", drop = FALSE) # collect remaining combinations icomb$collect() library(foreach) foreach(x = icombinations(5, 2), .combine=c) %do% { sum(x) }