Generate sparse dummy variables

Usage

sparse_dummy(x, one_hot = TRUE)

Arguments

x: A factor.
one_hot: A single logical value. Should the first factor level be included or not. Defaults to FALSE.

Value

A list of sparse integer dummy variables.

Details

Only factor variables can be used with sparse_dummy(). A call to as.factor() would be required for any other type of data.

If only a single level is present after one_hot takes effect. Then the vector produced won't be sparse.

A missing value at the ith element will produce missing values for all dummy variables at thr ith position.

Examples

x <- factor(c("a", "a", "b", "c", "d", "b"))

sparse_dummy(x, one_hot = FALSE)
#> $b
#> [1] 0 0 1 0 0 1
#> 
#> $c
#> [1] 0 0 0 1 0 0
#> 
#> $d
#> [1] 0 0 0 0 1 0
#> 

x <- factor(c("a", "a", "b", "c", "d", "b"))

sparse_dummy(x, one_hot = TRUE)
#> $a
#> [1] 1 1 0 0 0 0
#> 
#> $b
#> [1] 0 0 1 0 0 1
#> 
#> $c
#> [1] 0 0 0 1 0 0
#> 
#> $d
#> [1] 0 0 0 0 1 0
#> 

x <- factor(c("a", NA, "b", "c", "d", NA))

sparse_dummy(x, one_hot = FALSE)
#> $b
#> [1]  0 NA  1  0  0 NA
#> 
#> $c
#> [1]  0 NA  0  1  0 NA
#> 
#> $d
#> [1]  0 NA  0  0  1 NA
#> 

x <- factor(c("a", NA, "b", "c", "d", NA))

sparse_dummy(x, one_hot = TRUE)
#> $a
#> [1]  1 NA  0  0  0 NA
#> 
#> $b
#> [1]  0 NA  1  0  0 NA
#> 
#> $c
#> [1]  0 NA  0  1  0 NA
#> 
#> $d
#> [1]  0 NA  0  0  1 NA
#>