Modifies elements of a vector selectively, similar to the functions in purrr.

modify_if() applies a predicate function .p to all elements of .x and applies .f to those elements of .x where .p evaluates to TRUE.

modify_at() applies .f to those elements of .x selected via .at.

modify_if(.x, .p, .f, ...)

modify_at(.x, .at, .f, ...)

Arguments

.x

:: vector().

.p

:: function()
Predicate function.

.f

:: function()
Function to apply on .x.

...

:: any
Additional arguments passed to .f.

.at

:: (integer() | character())
Index vector to select elements from .x.

Examples

x = modify_if(iris, is.factor, as.character) str(x)
#> 'data.frame': 150 obs. of 5 variables: #> $ Sepal.Length: num 5.1 4.9 4.7 4.6 5 5.4 4.6 5 4.4 4.9 ... #> $ Sepal.Width : num 3.5 3 3.2 3.1 3.6 3.9 3.4 3.4 2.9 3.1 ... #> $ Petal.Length: num 1.4 1.4 1.3 1.5 1.4 1.7 1.4 1.5 1.4 1.5 ... #> $ Petal.Width : num 0.2 0.2 0.2 0.2 0.2 0.4 0.3 0.2 0.2 0.1 ... #> $ Species : chr "setosa" "setosa" "setosa" "setosa" ...
x = modify_at(iris, 5, as.character) x = modify_at(iris, "Sepal.Length", sqrt) str(x)
#> 'data.frame': 150 obs. of 5 variables: #> $ Sepal.Length: num 2.26 2.21 2.17 2.14 2.24 ... #> $ Sepal.Width : num 3.5 3 3.2 3.1 3.6 3.9 3.4 3.4 2.9 3.1 ... #> $ Petal.Length: num 1.4 1.4 1.3 1.5 1.4 1.7 1.4 1.5 1.4 1.5 ... #> $ Petal.Width : num 0.2 0.2 0.2 0.2 0.2 0.4 0.3 0.2 0.2 0.1 ... #> $ Species : Factor w/ 3 levels "setosa","versicolor",..: 1 1 1 1 1 1 1 1 1 1 ...