我在Python中有一个分类问题。我想找出哪些是分类中最重要的特征。我的数据是混合的,一些列是分类值,一些不是分类值。我正在使用OneHotEncoder
和Normalizer
进行转换:
columns_for_vectorization = ['A', 'B', 'C', 'D', 'E']columns_for_normalization = ['F', 'G', 'H']transformerVectoriser = ColumnTransformer(transformers=[('Vector Cat', OneHotEncoder(handle_unknown = "ignore"), columns_for_vectorization), ('Normalizer', Normalizer(), columns_for_normalization)], remainder='passthrough') # 默认是丢弃未转换的列
之后,我分割了我的数据并进行了转换:
x_train, x_test, y_train, y_test = train_test_split(features, results, test_size = 0.25, random_state=0)x_train = transformerVectoriser.fit_transform(x_train)x_test = transformerVectoriser.transform(x_test)
然后,我训练我的模型:
clf = RandomForestClassifier(max_depth = 5, n_estimators = 50, random_state = 0)model = clf.fit(x_train, y_train)
接着,我打印最重要的特征:
print(model.feature_importances_)
我得到的结果类似于这样:
[1.40910562e-03 1.46133832e-03 4.05058130e-03 3.92205197e-03 2.13243521e-03 5.78555893e-03 1.51927254e-03 1.14987114e-03 ... 6.37840204e-04 7.21061812e-04 5.77726129e-04 5.32382587e-04]
问题在于,最初我有8个特征,但由于转换,我现在有超过20个特征(因为分类数据)。我该如何处理这个问题?我如何知道哪个最初的特征是最重要的?
回答:
尝试以下方法来获取由’Vector Cat’转换器处理的特征名称:
VectorCatNames = list(transformerVectoriser.transformers_[0][1]['Vector Cat'].get_feature_names(columns_for_vectorization))
然后,你的最终特征名称可以保存为:
feature_names = VectorCatNames + columns_for_normalization