Lumps the levels of a nominal variable that carries a known hierarchy (for
example countries grouped into continents). Only levels within the same
cluster are combined, which preserves interpretability and lets the algorithm
run substantially faster than the fully general lump_nominal().
Usage
lump_hierarchical(
data,
threshold,
clusters,
verbose = FALSE,
alternative_metric = c("mutual information", "bin count", "surplus"),
level_namer = default_level_namer
)Arguments
- data
Factor or character vector of the categorical data.
- threshold
The minimum number of samples each lumped level should contain.
- clusters
List of character vectors representing the levels that are allowed to be lumped together.
- verbose
Logical value dictating if values should be printed. Default:
FALSE.- alternative_metric
The metric that should be optimised for, if it is different from the default, the mutual information. For an explanation of the metrics see
vignette("metrics").- level_namer
Function that takes a character vector of the original levels in a lump and returns the name of the new lumped level. Default: concatenating the original levels with a "+" in between.
See also
maximum_mutual_information_hierarchical() for the underlying algorithm that this function wraps.
lump_nominal() for a more general version of this function that does not need the hierarchical structure in the data, but may be slower.
lump_hierarchical_supervised() for a supervised version of this function.
Examples
country <- c("Germany", "Netherlands", "France", "France", "China", "China",
"China", "China", "Vietnam", "Vietnam", "Japan", "Japan")
lump_hierarchical(
country,
4,
list(c("Germany", "Netherlands", "France"), c("China", "Vietnam", "Japan"))
)
#> [1] Germany+Netherlands+France Germany+Netherlands+France
#> [3] Germany+Netherlands+France Germany+Netherlands+France
#> [5] China China
#> [7] China China
#> [9] Vietnam+Japan Vietnam+Japan
#> [11] Vietnam+Japan Vietnam+Japan
#> Levels: China Germany+Netherlands+France Vietnam+Japan