Case statements returning a factor

Source: R/in_case_fct.R

These functions are equivalent to in_case(), switch_case(), grep_case(), fn_case(), and fn_switch_case() but return factors with their levels determined by the order of their case statements.

in_case_fct(..., preserve = FALSE, default = NA, ordered = FALSE)

switch_case_fct(x, ..., preserve = FALSE, default = NA, ordered = FALSE)

grep_case_fct(x, ..., preserve = FALSE, default = NA, ordered = FALSE)

fn_case_fct(x, fn, ..., preserve = FALSE, default = NA, ordered = FALSE)

fn_switch_case_fct(x, fn, ..., preserve = FALSE, default = NA, ordered = FALSE)

Arguments

...

<dynamic-dots> A sequence of two-sided formulas or named arguments.

  • Formulas: Elements of x that return TRUE when passed to fn with the left hand side (LHS) of each formula will be replaced with the value in the right hand side (RHS). The LHS must evaluate to a logical vector when passed to fn with x. The RHS must be of length 1 or the same length as all other RHS.

  • Named arguments: named arguments are passed as additional arguments to the function fn.

preserve

If TRUE, unmatched elements of x will be returned unmodified. (The elements may have their type coerced to be compatible with replacement values.) If FALSE, unmatched elements of x will be replaced with default. Defaults to FALSE.

default

If preserve is FALSE, a value to replace unmatched elements of x. Defaults to NA.

ordered

A logical. If TRUE, returns an ordered factor. If FALSE, returns an unordered factor.

x

A vector

fn

A function to apply to the left-hand side of each formula in ...

Either a quoted or unquoted function name, an anonymous function, or a purrr-style formula.

The function should take two inputs, the first being x and the second being the left-hand side of the formula. The function should return a logical vector, either of length 1 or the same length as x.

Value

A factor vector of length 1 or n, matching the length of the logical input or output vectors. Levels are determined by the order of inputs to .... Inconsistent lengths will generate an error.

See also

in_case(), switch_case(), grep_case(), fn_case(), and fn_case_fct() on which these functions are based.

Examples

1:10 %>%
  in_case_fct(
    . %% 2 == 0 ~ "even",
    . %% 2 == 1 ~ "odd"
  )
#>  [1] odd  even odd  even odd  even odd  even odd  even
#> Levels: even odd

switch_case_fct(
  c("a", "b", "c"),
  "c" ~ "cantaloupe",
  "b" ~ "banana",
  "a" ~ "apple"
)
#> [1] apple      banana     cantaloupe
#> Levels: cantaloupe banana apple

switch_case_fct(
  c("a", "b", "c", "d"),
  "c" ~ "cantaloupe",
  "b" ~ "banana",
  "a" ~ "apple"
)
#> [1] apple      banana     cantaloupe <NA>      
#> Levels: cantaloupe banana apple

switch_case_fct(
  c("a", "b", "c", "d"),
  "c" ~ "cantaloupe",
  "b" ~ "banana",
  "a" ~ "apple",
  preserve = TRUE
)
#> [1] apple      banana     cantaloupe d         
#> Levels: cantaloupe banana apple d

grep_case_fct(
  c("caterpillar", "dogwood", "catastrophe", "dogma"),
  "cat" ~ "feline",
  "dog" ~ "canine"
)
#> [1] feline canine feline canine
#> Levels: feline canine

fn_case_fct(
  c("a", "b", "c"),
  `%in%`,
  "c" ~ "cantaloupe",
  "b" ~ "banana",
  "a" ~ "apple"
)
#> [1] apple      banana     cantaloupe
#> Levels: cantaloupe banana apple