决策树、随机森林、GTB决策树练习

决策树以及加强版的随机森林、GTB决策树练习，数据集是网上下载的“泰坦尼克号乘客资料”。

#-*- coding:utf-8 -*-

#-------导入数据

import pandas as pd

titanic=pd.read_csv('h://123.txt')

#print(titanic.head())

#print(titanic.info())

X=titanic[['pclass','age','sex']]

y=titanic['survived']

#print(X.info())

#---------数据预处理

a=X['age'].mean()

print(a)

X['age'].fillna(a,inplace=True)

print(X.info())

from sklearn.cross_validation import train_test_split

X_train,X_test,y_train,y_test=train_test_split(X,y,test_size=0.25,random_state=33)

from sklearn.feature_extraction import DictVectorizer

vec=DictVectorizer(sparse=False)

X_train=vec.fit_transform(X_train.to_dict(orient='record'))

X_test=vec. transform(X_test.to_dict(orient='record'))

#print(vec.feature_names_)

#-------调用决策树模型

from sklearn.tree import DecisionTreeClassifier

dtc=DecisionTreeClassifier()

dtc.fit(X_train,y_train)

y_predict_dtc=dtc.predict(X_test)

#--------调用随机森林模型

from sklearn.ensemble import RandomForestClassifier

rfc=RandomForestClassifier()

rfc.fit(X_train,y_train)

y_predict_rfc=rfc.predict(X_test)

#-------调用GBT决策树模型

from sklearn.ensemble import GradientBoostingClassifier

gbc=GradientBoostingClassifier()

gbc.fit(X_train,y_train)

y_predict_gbc=gbc.predict(X_test)

#-------性能分析

from sklearn.metrics import classification_report

print('决策树分类准确率：',dtc.score(X_test,y_test))

print(classification_report(y_test,y_predict_dtc))

print('随机森林分类准确率：',rfc.score(X_test,y_test))

print(classification_report(y_test,y_predict_rfc))

print('GTB决策树准确率：',gbc.score(X_test,y_test))

print(classification_report(y_test,y_predict_gbc))

结果如下：GTB决策树最好，随机森林最差（。。。无语）。