資源簡介
我選用了一個經典數據集來展示如何構建一個決策樹模型,這個數據集是——Iris 鳶尾花數據集。里面有我進行數據預處理,分析,優化參數,訓練模型以及最終分析決策樹的代碼。

代碼片段和文件信息
import?numpy?as?np
from?sklearn.tree?import?DecisionTreeRegressor
import?matplotlib.pyplot?as?plt
import?pandas?as?pd
iris_data?=?pd.read_csv(‘iris.csv‘)
iris_data?=?iris_data.loc[(iris_data[‘Species‘]?!=?‘setosa‘)?|?(iris_data[‘Sepal.Width‘]?>=?2.5)]
from?sklearn.model_selection?import?train_test_split
#?#將75%的數據放入訓練集,25%的數據放入測試集
all_inputs?=?iris_data[[‘Sepal.Length‘?‘Sepal.Width‘?‘Petal.Length‘?‘Petal.Width‘]]
all_classes?=?iris_data[‘Species‘].values
from?sklearn.tree?import?DecisionTreeClassifier
#使用上述得到的參數
clf=DecisionTreeClassifier(class_weight=None?criterion=‘gini‘?max_depth=2
????????????max_features=3?max_leaf_nodes=None?min_impurity_decrease=0.0
????????????min_impurity_split=None?min_samples_leaf=1
????????????min_samples_split=2?min_weight_fraction_leaf=0.0
????????????presort=False?random_state=None?splitter=‘best‘)
(X_train?X_test?Y_train?Y_test)?=?train_test_split(all_inputs?all_classestest_size=0.25?random_state=0)
clf.fit(X_train?Y_train)
from?IPython.display?import?Image
from?sklearn?import?tree
import?pydotplus
dot_data?=?tree.export_graphviz(clf?out_file=None
?????????????????????????feature_names=[‘Sepal.Length‘?‘Sepal.Width‘?‘Petal.Length‘?‘Petal.Width‘]???#對應特征的名字
?????????????????????????class_names=[‘Setosa‘‘Versicolour‘‘Virginica‘]????#對應類別的名字
?????????????????????????filled=True?rounded=True
?????????????????????????special_characters=True)
graph?=?pydotplus.graph_from_dot_data(dot_data)
graph.write_png(‘flower-de-luce.png‘)????#保存圖像
Image(graph.create_png())
?屬性????????????大小?????日期????時間???名稱
-----------?---------??----------?-----??----
????.CA....??????1683??2020-03-11?21:03??iris\GeneratingDecisionTree.py
????.CA....??????1396??2020-03-11?20:48??iris\getParameters.py
????.CA....??????4978??2020-03-11?16:30??iris\iris.csv
????.CA....???????890??2020-03-11?20:23??iris\preprocessing.py
????.CA....??????1272??2020-03-11?21:10??iris\printFeature.py
????.CA....??????1397??2020-03-11?20:48??iris\use.py
????.C.D...?????????0??2020-03-11?21:19??iris
-----------?---------??----------?-----??----
????????????????11616????????????????????7
評論
共有 條評論