names0 creates a series of num names with a common prefix. The names are numbered with leading zeros (e.g. prefix01-prefix10 instead of prefix1-prefix10). dummy_names can be used for renaming unordered and ordered dummy variables (in step_dummy()).

names0(num, prefix = "x")

dummy_names(var, lvl, ordinal = FALSE, sep = "_")

Arguments

num

A single integer for how many elements are created.

prefix

A character string that will start each name.

var

A single string for the original factor name.

lvl

A character vectors of the factor levels (in order). When used with step_dummy(), lvl would be the suffixes that result after model.matrix is called (see the example below).

ordinal

A logical; was the original factor ordered?

sep

A single character value for the separator between the names and levels.

Value

names0 returns a character string of length num and dummy_names generates a character vector the same length as lvl.

Details

When using dummy_names(), factor levels that are not valid variable names (e.g. "some text with spaces") will be changed to valid names by base::make.names(); see example below. This function will also change the names of ordinal dummy variables. Instead of values such as ".L", ".Q", or "^4", ordinal dummy variables are given simple integer suffixes such as "_1", "_2", etc.

Examples

names0(9, "a")
#> [1] "a1" "a2" "a3" "a4" "a5" "a6" "a7" "a8" "a9"
names0(10, "a")
#>  [1] "a01" "a02" "a03" "a04" "a05" "a06" "a07" "a08" "a09" "a10"

example <- data.frame(x = ordered(letters[1:5]),
                      y = factor(LETTERS[1:5]),
                      z = factor(paste(LETTERS[1:5], 1:5)))

dummy_names("y", levels(example$y)[-1])
#> [1] "y_B" "y_C" "y_D" "y_E"
dummy_names("z", levels(example$z)[-1])
#> [1] "z_B.2" "z_C.3" "z_D.4" "z_E.5"

after_mm <- colnames(model.matrix(~x, data = example))[-1]
after_mm
#> [1] "x.L" "x.Q" "x.C" "x^4"
levels(example$x)
#> [1] "a" "b" "c" "d" "e"

dummy_names("x", substring(after_mm, 2), ordinal = TRUE)
#> [1] "x_1" "x_2" "x_3" "x_4"