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Case statements returning a list

Source: R/in_case_list.R
in_case_list.Rd

These functions are equivalent to in_case(), switch_case(), grep_case(), fn_case(), and fn_switch_case() but return lists.

Usage

in_case_list(
  ...,
  .preserve = FALSE,
  .default = NA,
  preserve = deprecated(),
  default = deprecated()
)

switch_case_list(
  x,
  ...,
  .preserve = FALSE,
  .default = NA,
  .exhaustive = FALSE,
  preserve = deprecated(),
  default = deprecated()
)

grep_case_list(
  x,
  ...,
  .preserve = FALSE,
  .default = NA,
  .exhaustive = FALSE,
  preserve = deprecated(),
  default = deprecated()
)

fn_case_list(
  x,
  fn,
  ...,
  .preserve = FALSE,
  .default = NA,
  .exhaustive = FALSE,
  preserve = deprecated(),
  default = deprecated()
)

fn_switch_case_list(
  x,
  fn,
  ...,
  .preserve = FALSE,
  .default = NA,
  .exhaustive = FALSE,
  preserve = deprecated(),
  default = deprecated()
)

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, 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, default

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

x

A vector

.exhaustive

If TRUE, unmatched elements of x will result in an error. This can be useful to ensure you aren't accidentally forgetting to recode any values. Defaults to FALSE.

Note that if .preserve is TRUE, .exhaustive will never have any effect.

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 list of length 1 or n, matching the length of the logical input vector.

Details

This can be useful when returning a non-atomic value and/or when you want to create a list column inside a tibble.

See also

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

Examples

1:3 %>%
  in_case_list(
    . < 2    ~ mtcars,
    .default = letters
  )
#> [[1]]
#>                      mpg cyl  disp  hp drat    wt  qsec vs am gear carb
#> Mazda RX4           21.0   6 160.0 110 3.90 2.620 16.46  0  1    4    4
#> Mazda RX4 Wag       21.0   6 160.0 110 3.90 2.875 17.02  0  1    4    4
#> Datsun 710          22.8   4 108.0  93 3.85 2.320 18.61  1  1    4    1
#> Hornet 4 Drive      21.4   6 258.0 110 3.08 3.215 19.44  1  0    3    1
#> Hornet Sportabout   18.7   8 360.0 175 3.15 3.440 17.02  0  0    3    2
#> Valiant             18.1   6 225.0 105 2.76 3.460 20.22  1  0    3    1
#> Duster 360          14.3   8 360.0 245 3.21 3.570 15.84  0  0    3    4
#> Merc 240D           24.4   4 146.7  62 3.69 3.190 20.00  1  0    4    2
#> Merc 230            22.8   4 140.8  95 3.92 3.150 22.90  1  0    4    2
#> Merc 280            19.2   6 167.6 123 3.92 3.440 18.30  1  0    4    4
#> Merc 280C           17.8   6 167.6 123 3.92 3.440 18.90  1  0    4    4
#> Merc 450SE          16.4   8 275.8 180 3.07 4.070 17.40  0  0    3    3
#> Merc 450SL          17.3   8 275.8 180 3.07 3.730 17.60  0  0    3    3
#> Merc 450SLC         15.2   8 275.8 180 3.07 3.780 18.00  0  0    3    3
#> Cadillac Fleetwood  10.4   8 472.0 205 2.93 5.250 17.98  0  0    3    4
#> Lincoln Continental 10.4   8 460.0 215 3.00 5.424 17.82  0  0    3    4
#> Chrysler Imperial   14.7   8 440.0 230 3.23 5.345 17.42  0  0    3    4
#> Fiat 128            32.4   4  78.7  66 4.08 2.200 19.47  1  1    4    1
#> Honda Civic         30.4   4  75.7  52 4.93 1.615 18.52  1  1    4    2
#> Toyota Corolla      33.9   4  71.1  65 4.22 1.835 19.90  1  1    4    1
#> Toyota Corona       21.5   4 120.1  97 3.70 2.465 20.01  1  0    3    1
#> Dodge Challenger    15.5   8 318.0 150 2.76 3.520 16.87  0  0    3    2
#> AMC Javelin         15.2   8 304.0 150 3.15 3.435 17.30  0  0    3    2
#> Camaro Z28          13.3   8 350.0 245 3.73 3.840 15.41  0  0    3    4
#> Pontiac Firebird    19.2   8 400.0 175 3.08 3.845 17.05  0  0    3    2
#> Fiat X1-9           27.3   4  79.0  66 4.08 1.935 18.90  1  1    4    1
#> Porsche 914-2       26.0   4 120.3  91 4.43 2.140 16.70  0  1    5    2
#> Lotus Europa        30.4   4  95.1 113 3.77 1.513 16.90  1  1    5    2
#> Ford Pantera L      15.8   8 351.0 264 4.22 3.170 14.50  0  1    5    4
#> Ferrari Dino        19.7   6 145.0 175 3.62 2.770 15.50  0  1    5    6
#> Maserati Bora       15.0   8 301.0 335 3.54 3.570 14.60  0  1    5    8
#> Volvo 142E          21.4   4 121.0 109 4.11 2.780 18.60  1  1    4    2
#> 
#> [[2]]
#>  [1] "a" "b" "c" "d" "e" "f" "g" "h" "i" "j" "k" "l" "m" "n" "o" "p" "q" "r" "s"
#> [20] "t" "u" "v" "w" "x" "y" "z"
#> 
#> [[3]]
#>  [1] "a" "b" "c" "d" "e" "f" "g" "h" "i" "j" "k" "l" "m" "n" "o" "p" "q" "r" "s"
#> [20] "t" "u" "v" "w" "x" "y" "z"
#>