`if_else()`

is a vectorized if-else. Compared to the base R equivalent,
`ifelse()`

, this function allows you to handle missing values in the
`condition`

with `missing`

and always takes `true`

, `false`

, and `missing`

into account when determining what the output type should be.

## Arguments

- condition
A logical vector

- true, false
Vectors to use for

`TRUE`

and`FALSE`

values of`condition`

.Both

`true`

and`false`

will be recycled to the size of`condition`

.`true`

,`false`

, and`missing`

(if used) will be cast to their common type.- missing
If not

`NULL`

, will be used as the value for`NA`

values of`condition`

. Follows the same size and type rules as`true`

and`false`

.- ...
These dots are for future extensions and must be empty.

- ptype
An optional prototype declaring the desired output type. If supplied, this overrides the common type of

`true`

,`false`

, and`missing`

.- size
An optional size declaring the desired output size. If supplied, this overrides the size of

`condition`

.

## Value

A vector with the same size as `condition`

and the same type as the common
type of `true`

, `false`

, and `missing`

.

Where `condition`

is `TRUE`

, the matching values from `true`

, where it is
`FALSE`

, the matching values from `false`

, and where it is `NA`

, the matching
values from `missing`

, if provided, otherwise a missing value will be used.

## Examples

```
x <- c(-5:5, NA)
if_else(x < 0, NA, x)
#> [1] NA NA NA NA NA 0 1 2 3 4 5 NA
# Explicitly handle `NA` values in the `condition` with `missing`
if_else(x < 0, "negative", "positive", missing = "missing")
#> [1] "negative" "negative" "negative" "negative" "negative" "positive"
#> [7] "positive" "positive" "positive" "positive" "positive" "missing"
# Unlike `ifelse()`, `if_else()` preserves types
x <- factor(sample(letters[1:5], 10, replace = TRUE))
ifelse(x %in% c("a", "b", "c"), x, NA)
#> [1] NA NA 2 NA 3 1 NA 1 3 NA
if_else(x %in% c("a", "b", "c"), x, NA)
#> [1] <NA> <NA> b <NA> c a <NA> a c <NA>
#> Levels: a b c d e
# `if_else()` is often useful for creating new columns inside of `mutate()`
starwars %>%
mutate(category = if_else(height < 100, "short", "tall"), .keep = "used")
#> # A tibble: 87 × 2
#> height category
#> <int> <chr>
#> 1 172 tall
#> 2 167 tall
#> 3 96 short
#> 4 202 tall
#> 5 150 tall
#> 6 178 tall
#> 7 165 tall
#> 8 97 short
#> 9 183 tall
#> 10 182 tall
#> # … with 77 more rows
```