A data frame with columns named as the inputs, containing all input
combinations.
Examples
combinations(a =1:2, b =letters[1:3], c =LETTERS[1:2])#> a b c#> 1 1 a A#> 2 2 a A#> 3 1 b A#> 4 2 b A#> 5 1 c A#> 6 2 c A#> 7 1 a B#> 8 2 a B#> 9 1 b B#> 10 2 b B#> 11 1 c B#> 12 2 c B