배깅(Bagging)

Jane의 study note.·2022년 11월 30일
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사이킷런 Sklearn

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10/19

0. 핵심개념 및 사이킷런 알고리즘 API 링크

ensemble

Part1. 분류(Classification)

1. 분석 데이터 준비

import warnings
warnings.filterwarnings("ignore")
import pandas as pd
data1=pd.read_csv('breast-cancer-wisconsin.csv', encoding='utf-8')
X=data1[data1.columns[1:10]]
y=data1[["Class"]]

from sklearn.model_selection import train_test_split
X_train, X_test, y_train, y_test=train_test_split(X, y, stratify=y, random_state=42)

from sklearn.preprocessing import MinMaxScaler
scaler=MinMaxScaler()
scaler.fit(X_train)
X_scaled_train=scaler.transform(X_train)
X_scaled_test=scaler.transform(X_test)

2. 모델적용

from sklearn.svm import SVC
from sklearn.ensemble import BaggingClassifier
model = BaggingClassifier(base_estimator=SVC(), n_estimators=10, random_state=0)
model.fit(X_scaled_train, y_train)
pred_train=model.predict(X_scaled_train)
model.score(X_scaled_train, y_train)

0.982421875

from sklearn.metrics import confusion_matrix
confusion_train=confusion_matrix(y_train, pred_train)
print("훈련데이터 오차행렬:\n", confusion_train)

훈련데이터 오차행렬:
 [[329   4]
 [  5 174]]
 
from sklearn.metrics import classification_report
cfreport_train=classification_report(y_train, pred_train)
print("분류예측 레포트:\n", cfreport_train)

분류예측 레포트:
               precision    recall  f1-score   support

           0       0.99      0.99      0.99       333
           1       0.98      0.97      0.97       179

    accuracy                           0.98       512
   macro avg       0.98      0.98      0.98       512
weighted avg       0.98      0.98      0.98       512

pred_test=model.predict(X_scaled_test)
model.score(X_scaled_test, y_test)

0.9590643274853801

confusion_test=confusion_matrix(y_test, pred_test)
print("테스트데이터 오차행렬:\n", confusion_test)

테스트데이터 오차행렬:
 [[106   5]
 [  2  58]]
 
from sklearn.metrics import classification_report
cfreport_test=classification_report(y_test, pred_test)
print("분류예측 레포트:\n", cfreport_test)

분류예측 레포트:
               precision    recall  f1-score   support

           0       0.98      0.95      0.97       111
           1       0.92      0.97      0.94        60

    accuracy                           0.96       171
   macro avg       0.95      0.96      0.96       171
weighted avg       0.96      0.96      0.96       171

Part2. 회귀(Regression)

1. 분석 데이터 준비

data2=pd.read_csv('house_price.csv', encoding='utf-8')
X=data2[data2.columns[1:5]]
y=data2[["house_value"]]

from sklearn.model_selection import train_test_split
X_train, X_test, y_train, y_test=train_test_split(X, y, random_state=42)

from sklearn.preprocessing import MinMaxScaler
scaler=MinMaxScaler()
scaler.fit(X_train)
X_scaled_train=scaler.transform(X_train)
X_scaled_test=scaler.transform(X_test)

2. 모델적용

from sklearn.neighbors import KNeighborsRegressor
from sklearn.ensemble import BaggingRegressor
model = BaggingRegressor(base_estimator=KNeighborsRegressor(), n_estimators=10, random_state=0)
model.fit(X_scaled_train, y_train)
pred_train=model.predict(X_scaled_train)
model.score(X_scaled_train, y_train)

0.6928982134381334

pred_test=model.predict(X_scaled_test)
model.score(X_scaled_test, y_test)

0.5612676280708411

# RMSE (Root Mean Squared Error)
import numpy as np
from sklearn.metrics import mean_squared_error 
MSE_train = mean_squared_error(y_train, pred_train)
MSE_test = mean_squared_error(y_test, pred_test)
print("훈련   데이터 RMSE:", np.sqrt(MSE_train))
print("테스트 데이터 RMSE:", np.sqrt(MSE_test))

훈련   데이터 RMSE: 52892.27111989147
테스트 데이터 RMSE: 63323.12131927774

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