Extract Node List from a Vector or Unsupported Object

When called on an atomic vector (character, numeric, integer, logical, factor), returns the unique values as a node list with a name column (preserving order of first appearance) and an n column giving the frequency of each value. For all other unsupported types, an informative error is raised.

Usage

# Default S3 method
nodelist(input_object, ...)

Arguments

input_object

An atomic vector, or an object for which no specific nodelist method exists.

...

Additional arguments (currently unused)

Value

A data.frame with columns name (unique values in order of first appearance) and n (frequency count). For unsupported types, an error is raised.

Examples

# Character vector
nodelist(c("A", "B", "C", "A", "B"))
#>   name n
#> 1    A 2
#> 2    B 2
#> 3    C 1

# Numeric vector
nodelist(c(1, 2, 3, 2, 1))
#>   name n
#> 1    1 2
#> 2    2 2
#> 3    3 1

# Unsupported type
try(nodelist(as.formula(y ~ x)))
#> Error in nodelist.default(as.formula(y ~ x)) : 
#>   nodelist() does not support objects of class 'formula'. Supported classes: vector, data.frame, list, randomForest, tree, rpart, xgb.Booster, gbm.