Collapse factor levels with additional controls

Collapses factor levels into manually defined groups like forcats::fct_collapse(), with additional options to control behavior when specified levels don't exist in the data and to order factor levels in the order listed.

Usage

fct_collapse_alt(
  .f,
  ...,
  other_level = NULL,
  reorder = TRUE,
  unknown_levels = c("ignore", "warn", "error")
)

Arguments

.f

A factor (or character vector).

...

A series of named character vectors. The levels in each vector will be replaced with the name.

other_level

Value of level used for "other" values not named in .... If NULL, no extra level is created.

reorder

If TRUE, the collapsed levels are ordered in the order they are listed in ..., followed by other_level if specified, and then existing levels.

unknown_levels

How to handle levels listed in ... that aren't present in the input factor .f. Options are:

• "ignore": ignore unknown levels without a warning (default),

• "warn": issue a warning and then ignore unknown levels,

• "error": raise an error.

Value

A factor with collapsed levels.

Examples

f <- factor(c("a", "b", "c", "d", "e", "f"))

fct_collapse_alt(f, EFG = c("e", "f", "g"), AB = c("a", "b"))
#> [1] AB  AB  c   d   EFG EFG
#> Levels: EFG AB c d
fct_collapse_alt(f, EFG = c("e", "f", "g"), AB = c("a", "b"), reorder = FALSE)
#> [1] AB  AB  c   d   EFG EFG
#> Levels: AB c d EFG
fct_collapse_alt(f, EFG = c("e", "f", "g"), AB = c("a", "b"), other_level = "other")
#> [1] AB    AB    other other EFG   EFG  
#> Levels: EFG AB other
# `unknown_levels = "warn"` mirrors behavior of `forcats::fct_collapse()`
# \donttest{
fct_collapse_alt(f, EFG = c("e", "f", "g"), AB = c("a", "b"), unknown_levels = "warn")
#> Warning: Unknown levels in `f`: g
#> [1] AB  AB  c   d   EFG EFG
#> Levels: EFG AB c d
# }