【Scikit-learn】糖尿病患者のデータセットで複数の機械学習モデルで特徴量の全ての組み合わせを検討（再チャレンジ）［Python］

＜セル１＞

from sklearn.datasets import load_diabetes
import pandas as pd

diabetes = load_diabetes()

df = pd.DataFrame(diabetes.data, columns=diabetes.feature_names)

df["target"] = diabetes.target

df

実行結果

＜セル２＞

import itertools
from sklearn.model_selection import train_test_split
from sklearn.linear_model import LinearRegression
from sklearn.linear_model import Lasso
from sklearn.linear_model import ElasticNet
from sklearn.linear_model import Ridge
from sklearn.svm import SVR
from sklearn.metrics import r2_score
import numpy as np

models = ["LinearRegression", "Lasso", "ElasticNet", "RidgeRegression", "SVR"]

trial=10

score_list = []; combination_list = []; model_list = []
std_list = []; max_list = []; min_list = []; score_std_list = []

for i in range(1, len(diabetes.feature_names)+1):
    print(i)
    for comb in itertools.combinations(diabetes.feature_names, i):
#         print(comb)
        
        x = df.loc[:, comb]
        y = df.loc[:, "target"]
        
#         print(x)
        
        for mod in models:
            pred_score = []
        
            for t in range(trial):
        
                x_train, x_test, y_train, y_test = train_test_split(x, y, test_size=0.2, train_size=0.8)
            
                if mod == "LinearRegression":
                    model = LinearRegression()
                elif mod == "Lasso":
                    model = Lasso()
                elif mod == "ElasticNet":
                    model = ElasticNet()
                elif mod == "RidgeRegression":
                    model = Ridge()
                elif mod == "SVR":
                    model = SVR()

                model.fit(x_train, y_train)
                pred = model.predict(x_test)
                pred_score.append(r2_score(y_test, pred))
#                 print(mod, r2_score(y_test, pred))

            combination_list.append(comb)
            score_list.append(np.average(np.array(pred_score)))
            std_list.append(np.std(np.array(pred_score)))
            max_list.append(np.max(np.array(pred_score)))
            min_list.append(np.min(np.array(pred_score)))
            model_list.append(mod)
                
results = pd.DataFrame()
results["Model_name"] = model_list
results["Combination"] = combination_list
results["Score"] = score_list
results["Max"] = max_list
results["Min"] = min_list
results["STD"] = std_list
results["Score/STD"] = results["Score"]/results["STD"]
results = results.sort_values("Score/STD", ascending=False)

results.head(10)

実行結果

＜セル３＞

ranking = 100

lr_count = results["Model_name"][:ranking][results["Model_name"] == "LinearRegression"].count()
lasso_count = results["Model_name"][:ranking][results["Model_name"] == "Lasso"].count()
en_count = results["Model_name"][:ranking][results["Model_name"] == "ElasticNet"].count()
rd_count = results["Model_name"][:ranking][results["Model_name"] == "RidgeRegression"].count()
svr_count = results["Model_name"][:ranking][results["Model_name"] == "SVR"].count()

model_count_list = [lr_count, lasso_count, en_count, rd_count, svr_count]

print(model_count_list)

実行結果
[8, 46, 0, 44, 2]

＜セル４＞

from matplotlib import pyplot as plt
%matplotlib inline

fig = plt.figure(figsize=(8,6))
plt.clf()

plt.pie(model_count_list, labels=models)

実行結果
([<matplotlib.patches.Wedge at 0x7fca3a5a6510>,
  <matplotlib.patches.Wedge at 0x7fca3a5a6990>,
  <matplotlib.patches.Wedge at 0x7fca3a5a6950>,
  <matplotlib.patches.Wedge at 0x7fca3a5b8050>,
  <matplotlib.patches.Wedge at 0x7fca3a5b8e90>],
 [Text(1.0654414787782402, 0.27355886989611045, 'LinearRegression'),
  Text(-0.4049370232742901, 1.0227541284110062, 'Lasso'),
  Text(-1.0654414659720242, -0.2735589197730251, 'ElasticNet'),
  Text(0.06906960848527893, -1.0978293989430645, 'RidgeRegression'),
  Text(1.0978294029847897, -0.06906954424390042, 'SVR')])

＜セル５＞

ranking = 100

lasso_score_ave = results["Score"][:ranking][results["Model_name"] == "Lasso"].mean()
lasso_std_ave = results["STD"][:ranking][results["Model_name"] == "Lasso"].mean()
rd_score_ave = results["Score"][:ranking][results["Model_name"] == "RidgeRegression"].mean()
rd_std_ave = results["STD"][:ranking][results["Model_name"] == "RidgeRegression"].mean()

print(lasso_ave, lasso_std_ave)
print(rd_score_ave, rd_std_ave)

実行結果
0.2920837830657702 0.0183727782298612
0.3654750225200919 0.021773240517050107