Multiclass

[jmrichardson]

Hi, I am trying to determine which classifiers support multiclass and following the FAQ it says to do the following:

isinstance(tree.hoeffding_adaptive_tree_classifier, base.BinaryClassifier)

However, I am getting this error:

AttributeError: module 'river.base' has no attribute 'BinaryClassifier'

[gbolmier]

Hi @jmrichardson 👋 Thanks for your interest in the library and reporting this error.

Unfortunately the documentation is outdated here, the base.BinaryClassifier and base.MultiClassifier have been deprecated in favor of a base.Classifier with a _multiclass property instead. Sorry for the inconvenience.

Nevertheless, python isinstance built-in method compares an object instance with a class so you can't pass the tree.hoeffding_adaptive_tree_classifier module to isinstance. Instead you want to pass an instantiated object:

isinstance(tree.HoeffdingAdaptiveTreeClassifier(), base.Classifier)

If your goal is to list all the river mutliclass classifiers, the following snippet should do the trick:

import importlib
import inspect
import river

def is_multiclassifier(obj):
    if hasattr(obj, '_multiclass'):
        try:
            if isinstance(obj(), river.base.Classifier):
                return obj._multiclass
            else:
                return False
        except:
            return False
    else:
        return False

for module in importlib.import_module('river').__all__:
    if module in ['datasets', 'synth']:
        continue
    for name, obj in inspect.getmembers(importlib.import_module(f'river.{module}'), is_multiclassifier):
        print(name)

>>> NoChangeClassifier
>>> PriorClassifier
>>> AdaptiveRandomForestClassifier
>>> SRPClassifier
>>> FFMClassifier
>>> FMClassifier
>>> FwFMClassifier
>>> HOFMClassifier
>>> ALMAClassifier
>>> LogisticRegression
>>> PAClassifier
>>> Perceptron
>>> SoftmaxRegression
>>> BernoulliNB
>>> ComplementNB
>>> GaussianNB
>>> MultinomialNB
>>> KNNADWINClassifier
>>> KNNClassifier
>>> SAMKNNClassifier
>>> ExtremelyFastDecisionTreeClassifier
>>> HoeffdingAdaptiveTreeClassifier
>>> HoeffdingTreeClassifier
>>> LabelCombinationHoeffdingTreeClassifier

Let us know if you have any other questions :)