Python機器學習筆記(七之二)：使用Scikit-Learn進行分類演算法比較

Yanwei Liu

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Apr 23, 2019

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線性機器學習演算法

1. Logistic 迴歸

# Logistic Regression Classification
import pandas
from sklearn import model_selection
from sklearn.linear_model import LogisticRegression
url = "https://raw.githubusercontent.com/jbrownlee/Datasets/master/pima-indians-diabetes.data.csv"
names = ['preg', 'plas', 'pres', 'skin', 'test', 'mass', 'pedi', 'age', 'class']
dataframe = pandas.read_csv(url, names=names)
array = dataframe.values
X = array[:,0:8]
Y = array[:,8]
seed = 7
kfold = model_selection.KFold(n_splits=10, random_state=seed)
model = LogisticRegression()
results = model_selection.cross_val_score(model, X, Y, cv=kfold)
print(results.mean())

2.LDA線性判別分析

# LDA Classification
import pandas
from sklearn import model_selection
from sklearn.discriminant_analysis import LinearDiscriminantAnalysis
url = "https://raw.githubusercontent.com/jbrownlee/Datasets/master/pima-indians-diabetes.data.csv"
names = ['preg', 'plas', 'pres', 'skin', 'test', 'mass', 'pedi', 'age', 'class']
dataframe = pandas.read_csv(url, names=names)
array = dataframe.values
X = array[:,0:8]
Y = array[:,8]
seed = 7
kfold = model_selection.KFold(n_splits=10, random_state=seed)
model = LinearDiscriminantAnalysis()
results = model_selection.cross_val_score(model, X, Y, cv=kfold)
print(results.mean())

非線性機器學習演算法

1. K-Nearest Neighbors

# KNN Classification
import pandas
from sklearn import model_selection
from sklearn.neighbors import KNeighborsClassifier
url = "https://raw.githubusercontent.com/jbrownlee/Datasets/master/pima-indians-diabetes.data.csv"
names = ['preg', 'plas', 'pres', 'skin', 'test', 'mass', 'pedi', 'age', 'class']
dataframe = pandas.read_csv(url, names=names)
array = dataframe.values
X = array[:,0:8]
Y = array[:,8]
random_state = 7
kfold = model_selection.KFold(n_splits=10, random_state=seed)
model = KNeighborsClassifier()
results = model_selection.cross_val_score(model, X, Y, cv=kfold)
print(results.mean())

2.Naive Bayes

# Gaussian Naive Bayes Classification
import pandas
from sklearn import model_selection
from sklearn.naive_bayes import GaussianNB
url = "https://raw.githubusercontent.com/jbrownlee/Datasets/master/pima-indians-diabetes.data.csv"
names = ['preg', 'plas', 'pres', 'skin', 'test', 'mass', 'pedi', 'age', 'class']
dataframe = pandas.read_csv(url, names=names)
array = dataframe.values
X = array[:,0:8]
Y = array[:,8]
seed = 7
kfold = model_selection.KFold(n_splits=10, random_state=seed)
model = GaussianNB()
results = model_selection.cross_val_score(model, X, Y, cv=kfold)
print(results.mean())

3.決策樹

# CART Classification
import pandas
from sklearn import model_selection
from sklearn.tree import DecisionTreeClassifier
url = "https://raw.githubusercontent.com/jbrownlee/Datasets/master/pima-indians-diabetes.data.csv"
names = ['preg', 'plas', 'pres', 'skin', 'test', 'mass', 'pedi', 'age', 'class']
dataframe = pandas.read_csv(url, names=names)
array = dataframe.values
X = array[:,0:8]
Y = array[:,8]
seed = 7
kfold = model_selection.KFold(n_splits=10, random_state=seed)
model = DecisionTreeClassifier()
results = model_selection.cross_val_score(model, X, Y, cv=kfold)
print(results.mean())

4.支持向量機(SVM)

# SVM Classification
import pandas
from sklearn import model_selection
from sklearn.svm import SVC
url = "https://raw.githubusercontent.com/jbrownlee/Datasets/master/pima-indians-diabetes.data.csv"
names = ['preg', 'plas', 'pres', 'skin', 'test', 'mass', 'pedi', 'age', 'class']
dataframe = pandas.read_csv(url, names=names)
array = dataframe.values
X = array[:,0:8]
Y = array[:,8]
seed = 7
kfold = model_selection.KFold(n_splits=10, random_state=seed)
model = SVC()
results = model_selection.cross_val_score(model, X, Y, cv=kfold)
print(results.mean())