第八章

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我是靠谱客的博主俏皮含羞草，最近开发中收集的这篇文章主要介绍第八章，觉得挺不错的，现在分享给大家，希望可以做个参考。

概述

#例题
import pandas as pd
import numpy as np
data=pd.read_csv("C:\data\data8.csv",encoding='gbk')
np.round(data.corr(method='pearson'),2)
from sklearn.linear_model import Lasso
lasso=Lasso(1000).fit(data.iloc[:,0:13],data['y'])
np.round(lasso.coef_,5)
np.sum(lasso.coef_!=0)
mask=lasso.coef_!=0
new_reg_data=data.iloc[:,mask]
new_reg_data.to_csv('C:\data\new_reg_data.csv')
print(new_reg_data.shape)
def GM11(x0): #自定义灰色预测函数
import numpy as np
x1 = x0.cumsum() #1-AGO序列
z1 = (x1[:len(x1)-1] + x1[1:])/2.0 #紧邻均值（MEAN）生成序列
z1 = z1.reshape((len(z1),1))
B = np.append(-z1, np.ones_like(z1), axis = 1)
Yn = x0[1:].reshape((len(x0)-1, 1))
[[a],[b]] = np.dot(np.dot(np.linalg.inv(np.dot(B.T, B)), B.T), Yn) #计算参数
f = lambda k: (x0[0]-b/a)*np.exp(-a*(k-1))-(x0[0]-b/a)*np.exp(-a*(k-2)) #还原值
delta = np.abs(x0 - np.array([f(i) for i in range(1,len(x0)+1)]))
C = delta.std()/x0.std()
P = 1.0*(np.abs(delta - delta.mean()) < 0.6745*x0.std()).sum()/len(x0)
return f, a, b, x0[0], C, P #返回灰色预测函数、a、b、首项、方差比、小残差概率
new_reg_data=pd.read_csv('C:\data\new_reg_data.csv')
data=pd.read_csv("C:\data\data8.csv",encoding='gbk')
new_reg_data.index=range(1994,2014)
new_reg_data.loc[2014]=None
new_reg_data.loc[2015]=None
l=['x1','x3','x4','x5','x6','x7','x8','x13']
for i in l:
f=GM11(new_reg_data.loc[range(1994,2014),i].as_matrix())[0]
new_reg_data.loc[2014,i]=f(len(new_reg_data)-1)
new_reg_data.loc[2015,i]=f(len(new_reg_data))
new_reg_data[i]=new_reg_data[i].round(2)
y=list(data['y'].values)
y.extend([np.nan,np.nan])
new_reg_data['y']=y
new_reg_data.to_excel('C:\data\new_reg_data_GM11.xlsx')
import pandas as pd
import numpy as np
from sklearn.svm import LinearSVR
import matplotlib.pyplot as plt
from sklearn.metrics import explained_variance_score,mean_absolute_error,mean_squared_error,
median_absolute_error,r2_score
data=pd.read_excel('C:\data\new_reg_data_GM11.xlsx')
feature=['x1','x3','x4','x5','x6','x7','x8','x13']
data_train=data.loc[range(1994,2014)].copy()
data_mean=data_train.mean()
data_std=data_train.std()
data_train=(data_train-data_mean)/data_std
x_train=data_train[feature].as_matrix()
y_train=data_train['y'].as_matrix()
linearsvr=LinearSVR().fit(x_train,y_train)
x=((data[feature]-data_mean[feature])/data_std[feature]).as_matrix()
data[u'y_pred']=linearsvr.predict(x)*data_std['y']+data_mean['y']
data.to_excel('C:\data\new_reg_data_GM11_revenue.xlsx')
print(data[['y','y_pred']])
print(data[['y','y_pred']].plot(subplots=True,style=['b-o','r-*'],xticks=data.index[::2]))

#操作题
import pandas as pd
data=pd.read_csv("C:\data\data88.csv",encoding='gbk')
np.round(data.corr(method='pearson'),2)


#实训1
import pandas as pd
import numpy as np
data=pd.read_csv("C:\data\income_tax.csv",encoding='gbk')
np.round(data.corr(method='pearson'),2)
#实训2
from sklearn.linear_model import Lasso
data.index=data['year']
data=data.drop(['year'],axis=1)
lasso=Lasso(1000).fit(data.iloc[:,0:10],data['y'])
mask=lasso.coef_!=0
new_data=data.iloc[:,mask]
#实训3
def GM11(x0): #自定义灰色预测函数
import numpy as np
x1 = x0.cumsum() #1-AGO序列
z1 = (x1[:len(x1)-1] + x1[1:])/2.0 #紧邻均值（MEAN）生成序列
z1 = z1.reshape((len(z1),1))
B = np.append(-z1, np.ones_like(z1), axis = 1)
Yn = x0[1:].reshape((len(x0)-1, 1))
[[a],[b]] = np.dot(np.dot(np.linalg.inv(np.dot(B.T, B)), B.T), Yn) #计算参数
f = lambda k: (x0[0]-b/a)*np.exp(-a*(k-1))-(x0[0]-b/a)*np.exp(-a*(k-2)) #还原值
delta = np.abs(x0 - np.array([f(i) for i in range(1,len(x0)+1)]))
C = delta.std()/x0.std()
P = 1.0*(np.abs(delta - delta.mean()) < 0.6745*x0.std()).sum()/len(x0)
return f, a, b, x0[0], C, P #返回灰色预测函数、a、b、首项、方差比、小残差概率
new_data.loc[2016]=None
new_data.loc[2017]=None
feature=['x1','x2','x3','x4','x5','x6','x7','x8','x9','x10']
for i in feature:
f=GM11(new_data.loc[range(2004,2016),i].as_matrix())[0]
new_data.loc[2016,i]=f(len(new_data)-1)
new_data.loc[2017,i]=f(len(new_data))
new_data[i]=new_data[i].round(2)
y=list(data['y'].values)
y.extend([np.nan,np.nan])
new_data['y']=y
data_train=data.loc[range(2004,2016)].copy()
data_mean=data_train.mean()
data_std=data_train.std()
data_train=(data_train-data_mean)/data_std
x_train=data_train[feature].as_matrix()
y_train=data_train['y'].as_matrix()
from sklearn.svm import LinearSVR
linearsvr=LinearSVR().fit(x_train,y_train)
x=((data[feature]-data_mean[feature])/data_std[feature]).as_matrix()
data[u'y_pred']=linearsvr.predict(x)*data_std['y']+data_mean['y']
print(data[['y','y_pred']])
print(data[['y','y_pred']].plot(subplots=True,style=['b-o','r-*'],xticks=data.index[::2]))
```cpp
# 实训1
import numpy as np
import pandas as pd
data=pd.read_csv("C:\data\income_tax.csv",encoding='gbk')
data = data.iloc[:-2,1:]
#求取原始数据特征之间的Pearson相关系数
Pearson = np.round(data.corr(method='pearson'),2)
# 实训2
# 使用Lasso回归方法进行关键特征选取
from sklearn.linear_model import Lasso
lasso = Lasso(10000,random_state=12)#1000是最大循环次数，调用Lasso函数
lasso.fit(data.iloc[:,0:10],data['y'])
print('相关系数为：n',np.round(lasso.coef_,5))
#计算相关系数非零的个数
print('相关系数非零个数为：',np.sum(lasso.coef_ != 0))
#返回一个相关系数是否为零的布尔数组
mask = lasso.coef_ != 0
print('相关系数是否为零：n',mask)
#将关键特征进行提取
new_data = data.iloc[:,mask]
print('新数据的维度为:',new_data.shape)
# 实训3
# (1) 使用灰色预测模型对个各特征在2014年和2015年的值进行预测
def GM11(x0): #自定义灰色预测函数
import numpy as np
x1 = x0.cumsum() #1-AGO序列
z1 = (x1[:len(x1)-1] + x1[1:])/2.0 #紧邻均值（MEAN）生成序列
z1 = z1.reshape((len(z1),1))
B = np.append(-z1, np.ones_like(z1), axis = 1)
Yn = x0[1:].reshape((len(x0)-1, 1))
[[a],[b]] = np.dot(np.dot(np.linalg.inv(np.dot(B.T, B)), B.T), Yn) #计算参数
f = lambda k: (x0[0]-b/a)*np.exp(-a*(k-1))-(x0[0]-b/a)*np.exp(-a*(k-2)) #还原值
delta = np.abs(x0 - np.array([f(i) for i in range(1,len(x0)+1)]))
C = delta.std()/x0.std()
P = 1.0*(np.abs(delta - delta.mean()) < 0.6745*x0.std()).sum()/len(x0)
return f, a, b, x0[0], C, P #返回灰色预测函数、a、b、首项、方差比、小残差概率
new_data.index = range(2004,2014)
new_data.loc[2014] = None
new_data.loc[2015] = None
l = ['x1','x2','x3','x4','x5','x7','x8','x9','x10']
for i in l:
f = GM11(new_data.loc[range(2004,2014),i].as_matrix())[0]
new_data.loc[2014,i] = f(len(new_data)-1)
new_data.loc[2015,i] = f(len(new_data))
new_data[i] = new_data[i].round(2)
y = list(data['y'].values)
y.extend([np.nan,np.nan])
new_data['y'] = y
print('2014年和2015年预测结果为：n',new_data.loc[2014:2015,:])
# (2) 建立支持向量机回归预测模型
from sklearn.svm import LinearSVR
from sklearn.metrics import explained_variance_score,mean_absolute_error,
median_absolute_error,r2_score
feature = ['x1','x2','x3','x4','x5','x7','x8','x9','x10']
data_train = new_data.loc[range(2004,2014)].copy()
data_mean = data_train.mean()
data_std = data_train.std()
data_train = (data_train - data_mean)/data_std#数据标准化
x_train = data_train[feature].as_matrix()#特征数据
#x_trains = data_train[feature].values
y_train = data_train['y'].as_matrix()#标签数据
linearsvr = LinearSVR()#调用函数
linearsvr.fit(x_train,y_train)#训练模型
x = ((new_data[feature] - data_mean[feature])/data_std[feature]).as_matrix()
new_data[u'y_pred'] = linearsvr.predict(x)*data_std['y']+data_mean['y']
print('真实值与预测值分别为：n',new_data[['y','y_pred']])
# (3) 对上述建立的企业所得税预测模型进行评价
data_y = new_data['y'].iloc[:-2]
data_y_pred = new_data['y_pred'].iloc[:-2]
print('平均绝对误差为：',mean_absolute_error(data_y,data_y_pred))
print('中值绝对误差为：',median_absolute_error(data_y,data_y_pred))
print('可解释方差值为：',explained_variance_score(data_y,data_y_pred))
print('R2值为：',r2_score(data_y,data_y_pred))