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kaggle-泰坦尼克号Titanic-3

时间:2017-12-05 11:49:53      阅读:137      评论:0      收藏:0      [点我收藏+]

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根据以上两篇的分析,下面我们还要对数据进行处理,观察Age和Fare两个属性,乘客的数值变化幅度较大!根据逻辑回归和梯度下降的了解,如果属性值之间scale差距较大,将对收敛速度造成较大影响,甚至不收敛!因此,我们需要运用scikit-learn里面的preprocessing模块对Age和Fare两个属性做一个scaling,即将其数值转化为[-1,1]范围内。

1 # 接下来我们将一些变化幅度较大的特征化到[-1,1]之内,这样可以加速logistic regression的收敛
2 import sklearn.preprocessing as preprocessing
3 scaler = preprocessing.StandardScaler()
4 age_scale_param = scaler.fit(df[Age])
5 df[Age_scaled] = scaler.fit_transform(df[Age],age_scale_param)
6 fare_scale_param = scaler.fit(df[Fare])
7 df[Fare_scaled] = scaler.fit_transform(df[Fare],fare_scale_param)
8 print(df)

 

PassengerId

Survived

Age

SibSp

Parch

Fare

Cabin_No

Cabin_Yes

Embarked_C

Embarked_Q

Embarked_S

Sex_female

Sex_male

Pclass_1

Pclass_2

Pclass_3

Age_scaled

Fare_scaled

0

1

0

22.000000

1

0

7.2500

1

0

0

0

1

0

1

0

0

1

-0.561417

-0.502445

1

2

1

38.000000

1

0

71.2833

0

1

1

0

0

1

0

1

0

0

0.613177

0.786845

2

3

1

26.000000

0

0

7.9250

1

0

0

0

1

1

0

0

0

1

-0.267768

-0.488854

3

4

1

35.000000

1

0

53.1000

0

1

0

0

1

1

0

1

0

0

0.392941

0.420730

4

5

0

35.000000

0

0

8.0500

1

0

0

0

1

0

1

0

0

1

0.392941

-0.486337

5

6

0

23.828953

0

0

8.4583

1

0

0

1

0

0

1

0

0

1

-0.427149

-0.478116

6

7

0

54.000000

0

0

51.8625

0

1

0

0

1

0

1

1

0

0

1.787771

0.395814

7

8

0

2.000000

3

1

21.0750

1

0

0

0

1

0

1

0

0

1

-2.029659

-0.224083

8

9

1

27.000000

0

2

11.1333

1

0

0

0

1

1

0

0

0

1

-0.194356

-0.424256

9

10

1

14.000000

1

0

30.0708

1

0

1

0

0

1

0

0

1

0

-1.148714

-0.042956

10

11

1

4.000000

1

1

16.7000

0

1

0

0

1

1

0

0

0

1

-1.882835

-0.312172

11

12

1

58.000000

0

0

26.5500

0

1

0

0

1

1

0

1

0

0

2.081420

-0.113846

12

13

0

20.000000

0

0

8.0500

1

0

0

0

1

0

1

0

0

1

-0.708241

-0.486337

13

14

0

39.000000

1

5

31.2750

1

0

0

0

1

0

1

0

0

1

0.686589

-0.018709

14

15

0

14.000000

0

0

7.8542

1

0

0

0

1

1

0

0

0

1

-1.148714

-0.490280

15

16

1

55.000000

0

0

16.0000

1

0

0

0

1

1

0

0

1

0

1.861183

-0.326267

16

17

0

2.000000

4

1

29.1250

1

0

0

1

0

0

1

0

0

1

-2.029659

-0.061999

17

18

1

32.066493

0

0

13.0000

1

0

0

0

1

0

1

0

1

0

0.177586

-0.386671

18

19

0

31.000000

1

0

18.0000

1

0

0

0

1

1

0

0

0

1

0.099292

-0.285997

19

20

1

29.518205

0

0

7.2250

1

0

1

0

0

1

0

0

0

1

-0.009489

-0.502949

20

21

0

35.000000

0

0

26.0000

1

0

0

0

1

0

1

0

1

0

0.392941

-0.124920

21

22

1

34.000000

0

0

13.0000

0

1

0

0

1

0

1

0

1

0

0.319529

-0.386671

22

23

1

15.000000

0

0

8.0292

1

0

0

1

0

1

0

0

0

1

-1.075302

-0.486756

23

24

1

28.000000

0

0

35.5000

0

1

0

0

1

0

1

1

0

0

-0.120944

0.066360

24

25

0

8.000000

3

1

21.0750

1

0

0

0

1

1

0

0

0

1

-1.589186

-0.224083

25

26

1

38.000000

1

5

31.3875

1

0

0

0

1

1

0

0

0

1

0.613177

-0.016444

26

27

0

29.518205

0

0

7.2250

1

0

1

0

0

0

1

0

0

1

-0.009489

-0.502949

27

28

0

19.000000

3

2

263.0000

0

1

0

0

1

0

1

1

0

0

-0.781653

4.647001

28

29

1

22.380113

0

0

7.8792

1

0

0

1

0

1

0

0

0

1

-0.533512

-0.489776

29

30

0

27.947206

0

0

7.8958

1

0

0

0

1

0

1

0

0

1

-0.124820

-0.489442

...

...

...

...

...

...

...

...

...

...

...

...

...

...

...

...

...

...

...

861

862

0

21.000000

1

0

11.5000

1

0

0

0

1

0

1

0

1

0

-0.634829

-0.416873

862

863

1

48.000000

0

0

25.9292

0

1

0

0

1

1

0

1

0

0

1.347299

-0.126345

863

864

0

10.888325

8

2

69.5500

1

0

0

0

1

1

0

0

0

1

-1.377148

0.751946

864

865

0

24.000000

0

0

13.0000

1

0

0

0

1

0

1

0

1

0

-0.414592

-0.386671

865

866

1

42.000000

0

0

13.0000

1

0

0

0

1

1

0

0

1

0

0.906826

-0.386671

866

867

1

27.000000

1

0

13.8583

1

0

1

0

0

1

0

0

1

0

-0.194356

-0.369389

867

868

0

31.000000

0

0

50.4958

0

1

0

0

1

0

1

1

0

0

0.099292

0.368295

868

869

0

25.977889

0

0

9.5000

1

0

0

0

1

0

1

0

0

1

-0.269391

-0.457142

869

870

1

4.000000

1

1

11.1333

1

0

0

0

1

0

1

0

0

1

-1.882835

-0.424256

870

871

0

26.000000

0

0

7.8958

1

0

0

0

1

0

1

0

0

1

-0.267768

-0.489442

871

872

1

47.000000

1

1

52.5542

0

1

0

0

1

1

0

1

0

0

1.273886

0.409741

872

873

0

33.000000

0

0

5.0000

0

1

0

0

1

0

1

1

0

0

0.246117

-0.547748

873

874

0

47.000000

0

0

9.0000

1

0

0

0

1

0

1

0

0

1

1.273886

-0.467209

874

875

1

28.000000

1

0

24.0000

1

0

1

0

0

1

0

0

1

0

-0.120944

-0.165189

875

876

1

15.000000

0

0

7.2250

1

0

1

0

0

1

0

0

0

1

-1.075302

-0.502949

876

877

0

20.000000

0

0

9.8458

1

0

0

0

1

0

1

0

0

1

-0.708241

-0.450180

877

878

0

19.000000

0

0

7.8958

1

0

0

0

1

0

1

0

0

1

-0.781653

-0.489442

878

879

0

27.947206

0

0

7.8958

1

0

0

0

1

0

1

0

0

1

-0.124820

-0.489442

879

880

1

56.000000

0

1

83.1583

0

1

1

0

0

1

0

1

0

0

1.934596

1.025945

880

881

1

25.000000

0

1

26.0000

1

0

0

0

1

1

0

0

1

0

-0.341180

-0.124920

881

882

0

33.000000

0

0

7.8958

1

0

0

0

1

0

1

0

0

1

0.246117

-0.489442

882

883

0

22.000000

0

0

10.5167

1

0

0

0

1

1

0

0

0

1

-0.561417

-0.436671

883

884

0

28.000000

0

0

10.5000

1

0

0

0

1

0

1

0

1

0

-0.120944

-0.437007

884

885

0

25.000000

0

0

7.0500

1

0

0

0

1

0

1

0

0

1

-0.341180

-0.506472

885

886

0

39.000000

0

5

29.1250

1

0

0

1

0

1

0

0

0

1

0.686589

-0.061999

886

887

0

27.000000

0

0

13.0000

1

0

0

0

1

0

1

0

1

0

-0.194356

-0.386671

887

888

1

19.000000

0

0

30.0000

0

1

0

0

1

1

0

1

0

0

-0.781653

-0.044381

888

889

0

16.232379

1

2

23.4500

1

0

0

0

1

1

0

0

0

1

-0.984830

-0.176263

889

890

1

26.000000

0

0

30.0000

0

1

1

0

0

0

1

1

0

0

-0.267768

-0.044381

890

891

0

32.000000

0

0

7.7500

1

0

0

1

0

0

1

0

0

1

0.172705

-0.492378

891 rows × 18 columns

接下来我们把需要的feature字段取出来,转成numpy格式,使用scikit-learn中的LogisticRegression建模。

1 from sklearn import linear_model
2 train_df = df.filter(regex=Survived|Age_.*|SibSp|Parch|Fare_.*|Cabin_.*|Embarked_.*|Sex_.*|Pclass_.*)
3 train_np = train_df.as_matrix()
4 y = train_np[:,0]
5 X = train_np[:,1:]
6 clf = linear_model.LogisticRegression(C=1.0,penalty=l1,tol=1e-6)
7 clf.fit(X,y)
8 print(clf)

接下来我们需要对测试数据集和训练数据集做一样的操作

 1 # #首先用同样的RandomForestRegressor模型填上丢失的年龄
 2 data_test = pd.read_csv("test.csv")
 3 data_test.loc[ (data_test.Fare.isnull()), Fare ] = 0
 4 
 5 tmp_df = data_test[[Age,Fare, Parch, SibSp, Pclass]]
 6 null_age = tmp_df[data_test.Age.isnull()].as_matrix()
 7 # 根据特征属性X预测年龄并补上
 8 X = null_age[:, 1:]
 9 predictedAges = rfr.predict(X)
10 data_test.loc[ (data_test.Age.isnull()), Age ] = predictedAges
11 
12 data_test = set_Cabin_type(data_test)
13 dummies_Cabin = pd.get_dummies(data_test[Cabin], prefix= Cabin)
14 dummies_Embarked = pd.get_dummies(data_test[Embarked], prefix= Embarked)
15 dummies_Sex = pd.get_dummies(data_test[Sex], prefix= Sex)
16 dummies_Pclass = pd.get_dummies(data_test[Pclass], prefix= Pclass)
17 
18 
19 df_test = pd.concat([data_test, dummies_Cabin, dummies_Embarked, dummies_Sex, dummies_Pclass], axis=1)
20 df_test.drop([Pclass, Name, Sex, Ticket, Cabin, Embarked], axis=1, inplace=True)
21 df_test[Age_scaled] = scaler.fit_transform(df_test[Age], age_scale_param)
22 df_test[Fare_scaled] = scaler.fit_transform(df_test[Fare], fare_scale_param)
23 
24 test = df_test.filter(regex=Age_.*|SibSp|Parch|Fare_.*|Cabin_.*|Embarked_.*|Sex_.*|Pclass_.*)
25 predictions = clf.predict(test)
26 result = pd.DataFrame({PassengerId:data_test[PassengerId].as_matrix(), Survived:predictions.astype(np.int32)})
27 result.to_csv("logistic_regression_predictions.csv", index=False)

最后我们将预测的结果保存在logistic_regression_predictions.csv文件里。到这里只是简单分析过后的一个baseline系统。

 

下面要判定一下当前模型所处状态(欠拟合或者过拟合)

这里面有个问题,前面不断地做特征工程,产生的特征越来越多,用这些特征来训练模型,会对训练集拟合得越来越好,同时也可能在逐步丧失泛化能力,从而在待测数据上表现不佳,也就是发生过拟合问题。

从另一个角度上说,如果模型在待测数据上表现不佳,除掉上述说的过拟合问题,有时候也存在欠拟合问题,也就是说在训练集上拟合的结果也不好。

对于过拟合和欠拟合,有两种优化方式:

1.过拟合

1)做一个feature selection,选较好的feature的subset来做training

2)提供更多的数据,从而弥补原始数据偏差,从而学习到的模型更准确

3)采用正则化,正则化方法包括L0正则、L1正则和L2正则,而正则一般是在目标函数之后加上对于的范数。但是在机器学习中一般使用L2正则。

2.欠拟合

1)添加其他特征项,有时候我们模型出现欠拟合的时候是因为特征项不够导致的,可以添加其他特征项来很好地解决。例如,“组合”、“泛化”、“相关性”三类特征是特征添加的重要手段。

2)添加多项式特征,这个在机器学习算法里面用的很普遍,例如将线性模型通过添加二次项或者三次项使模型泛化能力更强。

3)减少正则化参数,正则化的目的是用来防止过拟合的,但是现在模型出现了欠拟合,则需要减少正则化参数。

 scikit-learn里面的learning curve可以帮助我们判定模型现在所处的状态。这里我们画一下最先得到的baseline model的learning curve。

 1 import numpy as np
 2 import matplotlib.pyplot as plt
 3 from sklearn.learning_curve import learning_curve
 4 
 5 #用sklearn的learning_curve得到training_score和cv_score,使用matplotlib画出learning curve
 6 
 7 def plot_learning_curve(estimator,title,X,y,ylim=None,cv=None,n_jobs=1,train_sizes=np.linspace(.05,1.,20),verbose=0,plot=True):
 8     """
 9        画出data在某模型上的learning curve.
10        参数解释
11        ----------
12        estimator : 你用的分类器。
13        title : 表格的标题。
14        X : 输入的feature,numpy类型
15        y : 输入的target vector
16        ylim : tuple格式的(ymin, ymax), 设定图像中纵坐标的最低点和最高点
17        cv : 做cross-validation的时候,数据分成的份数,其中一份作为cv集,其余n-1份作为training(默认为3份)
18        n_jobs : 并行的的任务数(默认1)
19        """
20     train_sizes, train_scores, test_scores = learning_curve(
21         estimator, X, y, cv=cv, n_jobs=n_jobs, train_sizes=train_sizes, verbose=verbose)
22 
23     train_scores_mean = np.mean(train_scores, axis=1)
24     train_scores_std = np.std(train_scores, axis=1)
25     test_scores_mean = np.mean(test_scores, axis=1)
26     test_scores_std = np.std(test_scores, axis=1)
27 
28     if plot:
29         plt.figure()
30         plt.title(title)
31         if ylim is not None:
32             plt.ylim(*ylim)
33         plt.xlabel(train_sample)
34         plt.ylabel(score)
35         plt.gca().invert_yaxis()
36         plt.grid()
37 
38         plt.fill_between(train_sizes, train_scores_mean - train_scores_std, train_scores_mean + train_scores_std,
39                          alpha=0.1, color="b")
40         plt.fill_between(train_sizes, test_scores_mean - test_scores_std, test_scores_mean + test_scores_std,
41                          alpha=0.1, color="r")
42         plt.plot(train_sizes, train_scores_mean, o-, color="b", label="train_score")
43         plt.plot(train_sizes, test_scores_mean, o-, color="r", label="cross_validation_score")
44 
45         plt.legend(loc=best)
46         plt.draw()
47         plt.gca().invert_yaxis()
48         plt.show()
49 
50     midpoint = ((train_scores_mean[-1] + train_scores_std[-1]) + (test_scores_mean[-1] - test_scores_std[-1])) / 2
51     diff = (train_scores_mean[-1] + train_scores_std[-1]) - (test_scores_mean[-1] - test_scores_std[-1])
52     return midpoint, diff
53 
54 plot_learning_curve(clf, u"学习曲线", X, y)

结果如下(0.80656968448540245, 0.018258876711338634)

技术分享图片

从得到的结果来看,尽管learn——curve没有理论推导的光滑,但是仍可以看出,训练集和交叉验证集上的得分曲线走势还是符合预期的。

目前的曲线来看,我们的model并不处于overfitting的状态(overfitting的表现一般是训练集得分高,交叉验证集得分低很多,中间的gap比较大)。因此我们可以再做些feature engineering的工作,添加一些新的特征或者组合特征到模型中。

 

kaggle-泰坦尼克号Titanic-3

标签:1.4   另一个   png   ref   目的   figure   方式   技术分享   操作   

原文地址:http://www.cnblogs.com/freeman818/p/7867071.html

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