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