class_docstr: Splitter utilized to monitor nominal features in regression tasks.
  
  As the monitored feature is nominal, it already has well-defined partitions. Hence,
  this splitter simply keeps the split-enabling target statistics for each incoming
  category.
class_docstr_tok: ["Splitter","utilized","to","monitor","nominal","features","in","regression","tasks",".","As","the","monitored","feature","is","nominal",",","it","already","has","well-defined","partitions",".","Hence",",","this","splitter","simply","keeps","the","split-enabling","target","statistics","for","each","incoming","category","."]
code: def best_evaluated_split_suggestion(
      self, criterion, pre_split_dist, att_idx, binary_only
  ):
      current_best = BranchFactory()
      ordered_feature_values = sorted(list(self._statistics.keys()))
      if not binary_only and len(self._statistics) > 2:
          post_split_dist = [
              self._statistics[k] for k in ordered_feature_values
          ]
  
          merit = criterion.merit_of_split(
              pre_split_dist, post_split_dist
          )
          current_best = BranchFactory(
              merit,
              att_idx,
              ordered_feature_values,
              post_split_dist,
              numerical_feature=False,
              multiway_split=True,
          )
  
      for att_val in ordered_feature_values:
          actual_dist = self._statistics[att_val]
          remaining_dist = pre_split_dist - actual_dist
          post_split_dist = [actual_dist, remaining_dist]
  
          merit = criterion.merit_of_split(
              pre_split_dist, post_split_dist
          )
  
          if merit > current_best.merit:
              current_best = BranchFactory(
                  merit,
                  att_idx,
                  att_val,
                  post_split_dist,
                  numerical_feature=False,
                  multiway_split=False,
              )
  
      return current_best
  
file_path: river/river/tree/splitter/nominal_splitter_reg.py
imports: from __future__ import annotations
  import functools
  from river.stats import Var
  from river.utils import VectorDict
  from ..utils import BranchFactory
  from .base import Splitter
label_desc: Use image node_id 7 for calling the NominalSplitterReg obj's underlying member method code with example usage: obj.best_evaluated_split_suggestion(criterion, pre_split_dist, att_idx, binary_only) and returns: current_best