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()).
Usage
names0(num, prefix = "x")
dummy_names(var, lvl, ordinal = FALSE, sep = "_")
dummy_extract_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(),lvlwould be the suffixes that result aftermodel.matrixis 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"