Length-2 cycles; swap a pair of elements

Usage

swap(a, b)

Arguments

a, b: Integers

Details

Swaps two elements. Vectorized; uses standard recycling.

Value

Returns a permutation in cycle form

Author

Robin K. S. Hankin

Note

If the first argument equals the second, the identity permutation is returned.

Cycles of the form \((1n)\), that is, swap(1, n), are used extensively in inst/outer_automorphisms_of_S6.Rmd.

Examples


swap(2, 8)
#> [1] (28)

swap(5, 1:9)
#> [1] (15) (25) (35) (45) ()   (56) (57) (58) (59)

swap(1:8, 8:1)
#> [1] (18) (27) (36) (45) (45) (36) (27) (18)

swap(sample(9), sample(9))
#> [1] (69) ()   (69) (37) (28) (78) ()   (23) ()  

rcyc(10,4)^swap(1,9)
#>  [1] (2394) (2934) (2943) (2493) (2493) (2943) (2493) (2943) (2394) (2943)
#> [coerced from word form]