combs {caMassClass}R Documentation

All Combinations of k Elements from Vector v

Description

Finds all unordered combinations of k elements from vector v.

Usage

combs(v,k)

Arguments

v Any numeric vector
k Number of elements to choose from vector v. Integer smaller or equal than length of v.

Value

combs(v,k) (where v has length n) creates a matrix with n!/((n-k)! k!) (n choose k) rows and k columns containing all possible combinations of n elements taken k at a time.

Author(s)

Jarek Tuszynski (SAIC) jaroslaw.w.tuszynski@saic.com

See Also

I discovered recently that R packages already have two functions with similar capabilities: combinations from gTools package and nchoosek from vsn package. Also similar to Matlab's nchoosek function ( http://www.mathworks.com/access/helpdesk/help/techdoc/ref/nchoosek.html)

Examples

  #example: combs(1:3,2) returns matrix with following rows (1 2), (1 3), (2 3)
  combs(1:3,2)

[Package caMassClass version 1.0 Index]