Lengthens a Dataset by Combination of Columns

Creates a long dataset of "n" columns comprising the combinations of values from different columns.

lengthener(indt, n = 2)

Arguments

indt	The input dataset.
n	The number of columns expected. Passed on to combn.

Value

A data.table.

References

http://stackoverflow.com/q/35690478/1270695

Author

Ananda Mahto

Examples

mydf <- as.data.frame(matrix(c(1,2,3,4,0,0,1,1), byrow = TRUE, nrow = 2))
lengthener(mydf, 2)
#>     V1 V2
#>  1:  1  2
#>  2:  1  3
#>  3:  1  4
#>  4:  2  3
#>  5:  2  4
#>  6:  3  4
#>  7:  0  0
#>  8:  0  1
#>  9:  0  1
#> 10:  0  1
#> 11:  0  1
#> 12:  1  1
lengthener(mydf, 3)
#>    V1 V2 V3
#> 1:  1  2  3
#> 2:  1  2  4
#> 3:  1  3  4
#> 4:  2  3  4
#> 5:  0  0  1
#> 6:  0  0  1
#> 7:  0  1  1
#> 8:  0  1  1