Encode/factor

Low-level encoding and factor building

Usage

encode(x, from, to, strict = FALSE, exclude = NULL)

fact(x, levels = NULL, exclude = NULL)

Arguments

x

A vector of values

from, to

Vectors of the same length. Values in x are matched to from and replaced with the corresponding value in to.

strict

If TRUE, values in x that are not matched to from will be replaced with NA. If FALSE, they will be left unchanged.

exclude

Values in x that will not be matched when recoding; exclude will take priority over from in encode().

levels

A vector of unique values. If NULL, the unique values in x are used.

Value

encode() A vector of the same length as x with values replaced according to from and to.

fact() A factor vector with levels corresponding to the unique values in x (or levels if provided).

Details

encode() is a general purpose function for replacing values in a vector.

fact() is a low-level function for building factor vectors. It does not perform any sort()ing of levels (unlink base::factor()). Re-leveling can be done by applying encode() to the levels of a factor object.

Examples

fact(strsplit("factor function", "")[[1L]], exclude = " ")
#>  [1] f    a    c    t    o    r    <NA> f    u    n    c    t    i    o    n   
#> Levels: f a c t o r u n i

# encode() can be used to for the same utility as factor(x, levels, labels)
# (note: applying to levels can be more efficient)
(x <- fact(strsplit("jordan", "")[[1L]]))
#> [1] j o r d a n
#> Levels: j o r d a n
levels(x) <- encode(levels(x), from = c("a", "o"), to = "*")
x
#> [1] j * r d * n
#> Levels: j * r d n