If

Colin Fay

2019-04-08

if_ conditions

if_none(), if_any() and if_all() test the elements of the list.

if_all(1:10, ~ .x < 11, ~ return(letters[1:10]))
#>  [1] "a" "b" "c" "d" "e" "f" "g" "h" "i" "j"

if_any(1:10, is.numeric, ~ "Yay!")
#> [1] "Yay!"

if_none(1:10, is.character, ~ rnorm(10))
#>  [1]  0.1639942  1.6186677 -1.4342989  0.7978063 -2.3276527 -0.5471802
#>  [7] -0.7113301 -0.5626312  0.7712547 -0.2543223

The defaut for all .p is isTRUE(). So you can:

a <- c(FALSE, TRUE, TRUE, TRUE)

if_any(a, .f = ~ "nop!")
#> [1] "nop!"

if_then() performs a simple “if this then do that”:

if_then(1, is.numeric, ~ "nop!")
#> [1] "nop!"

if_not() runs .f if .p(.x) is not TRUE :

if_not(.x = 1, .p = is.character, ~ ".x is not a character")
#> [1] ".x is not a character"

And if_else() is a wrapper around base::ifelse().

If you want these function to return a value, you need to wrap these values into a mapper / a function. E.g, to return a vector, you’ll need to write if_then(1, is.numeric, ~ "Yay").

a <- if_else(1, is.numeric, ~ "Yay", ~ "Nay")
a
#> [1] "Yay"