版权声明：本文为博主原创文章，未经博主允许不得转载。 https://blog.csdn.net/mr_muli/article/details/84937234
- 机器学习之分类问题的性能度量
# -*- coding: utf-8 -*-
"""
Created on Mon Dec 10 10:54:09 2018
@author: muli
"""
from sklearn.metrics import accuracy_score,precision_score,recall_score,f1_score\
,fbeta_score,classification_report,confusion_matrix,precision_recall_curve,roc_auc_score\
,roc_curve
from sklearn.datasets import load_iris
from sklearn.multiclass import OneVsRestClassifier
from sklearn.svm import SVC
from sklearn.model_selection import train_test_split
import matplotlib.pyplot as plt
from sklearn.preprocessing import label_binarize
import numpy as np
def test_accuracy_score():
'''
测试 accuracy_score 的用法
:return: None
'''
y_true=[1,1,1,1,1,0,0,0,0,0]
y_pred=[0,0,1,1,0,0,1,1,0,0]
print('Accuracy Score(normalize=True):',accuracy_score(y_true,y_pred,normalize=True))
print('Accuracy Score(normalize=False):',accuracy_score(y_true,y_pred,normalize=False))
def test_precision_score():
'''
测试 precision_score 的用法
:return: None
'''
y_true=[1,1,1,1,1,0,0,0,0,0]
y_pred=[0,0,1,1,0,0,0,0,0,0]
print('Accuracy Score:',accuracy_score(y_true,y_pred,normalize=True))
print('Precision Score:',precision_score(y_true,y_pred))
def test_recall_score():
'''
测试 recall_score 的用法
:return: None
'''
y_true=[1,1,1,1,1,0,0,0,0,0]
y_pred=[0,0,1,1,0,0,0,0,0,0]
print('Accuracy Score:',accuracy_score(y_true,y_pred,normalize=True))
print('Precision Score:',precision_score(y_true,y_pred))
print('Recall Score:',recall_score(y_true,y_pred))
def test_f1_score():
'''
测试 f1_score 的用法
:return: None
'''
y_true=[1,1,1,1,1,0,0,0,0,0]
y_pred=[0,0,1,1,0,0,0,0,0,0]
print('Accuracy Score:',accuracy_score(y_true,y_pred,normalize=True))
print('Precision Score:',precision_score(y_true,y_pred))
print('Recall Score:',recall_score(y_true,y_pred))
print('F1 Score:',f1_score(y_true,y_pred))
def test_fbeta_score():
'''
测试 fbeta_score 的用法
:return: None
'''
y_true=[1,1,1,1,1,0,0,0,0,0]
y_pred=[0,0,1,1,0,0,0,0,0,0]
print('Accuracy Score:',accuracy_score(y_true,y_pred,normalize=True))
print('Precision Score:',precision_score(y_true,y_pred))
print('Recall Score:',recall_score(y_true,y_pred))
print('F1 Score:',f1_score(y_true,y_pred))
print('Fbeta Score(beta=0.001):',fbeta_score(y_true,y_pred,beta=0.001))
print('Fbeta Score(beta=1):',fbeta_score(y_true,y_pred,beta=1))
print('Fbeta Score(beta=10):',fbeta_score(y_true,y_pred,beta=10))
print('Fbeta Score(beta=10000):',fbeta_score(y_true,y_pred,beta=10000))
def test_classification_report():
'''
测试 classification_report 的用法
:return: None
'''
y_true=[1,1,1,1,1,0,0,0,0,0]
y_pred=[0,0,1,1,0,0,0,0,0,0]
print('Classification Report:\n',classification_report(y_true,y_pred,
target_names=["class_0","class_1"]))
def test_confusion_matrix():
'''
测试 confusion_matrix 的用法
:return: None
'''
y_true=[1,1,1,1,1,0,0,0,0,0]
y_pred=[0,0,1,1,0,0,0,0,0,0]
print('Confusion Matrix:\n',confusion_matrix(y_true,y_pred,labels=[0,1]))
def test_precision_recall_curve():
'''
测试 precision_recall_curve 的用法，并绘制 P-R 曲线
:return: None
'''
### 加载数据
iris=load_iris()
X=iris.data
y=iris.target
# 二元化标记
y = label_binarize(y, classes=[0, 1, 2])
n_classes = y.shape[1]
#### 添加噪音
np.random.seed(0)
n_samples, n_features = X.shape
X = np.c_[X, np.random.randn(n_samples, 200 * n_features)]
X_train,X_test,y_train,y_test=train_test_split(X,y,
test_size=0.5,random_state=0)
### 训练模型
clf=OneVsRestClassifier(SVC(kernel='linear', probability=True,random_state=0))
clf.fit(X_train,y_train)
y_score = clf.fit(X_train, y_train).decision_function(X_test)
### 获取 P-R
fig=plt.figure()
ax=fig.add_subplot(1,1,1)
precision = dict()
recall = dict()
for i in range(n_classes):
precision[i], recall[i], _ = precision_recall_curve(y_test[:, i],
y_score[:, i])
ax.plot(recall[i],precision[i],label="target=%s"%i)
ax.set_xlabel("Recall Score")
ax.set_ylabel("Precision Score")
ax.set_title("P-R")
ax.legend(loc='best')
ax.set_xlim(0,1.1)
ax.set_ylim(0,1.1)
ax.grid()
plt.show()
def test_roc_auc_score():
'''
测试 roc_curve、roc_auc_score 的用法，并绘制 ROC 曲线
:return: None
'''
### 加载数据
iris=load_iris()
X=iris.data
y=iris.target
# 二元化标记
y = label_binarize(y, classes=[0, 1, 2])
n_classes = y.shape[1]
#### 添加噪音
np.random.seed(0)
n_samples, n_features = X.shape
X = np.c_[X, np.random.randn(n_samples, 200 * n_features)]
X_train,X_test,y_train,y_test=train_test_split(X,y,
test_size=0.5,random_state=0)
### 训练模型
clf=OneVsRestClassifier(SVC(kernel='linear', probability=True,random_state=0))
clf.fit(X_train,y_train)
y_score = clf.fit(X_train, y_train).decision_function(X_test)
### 获取 ROC
fig=plt.figure()
ax=fig.add_subplot(1,1,1)
fpr = dict()
tpr = dict()
roc_auc=dict()
for i in range(n_classes):
fpr[i], tpr[i], _ = roc_curve(y_test[:, i],y_score[:, i])
# roc_auc[i] = roc_auc_score(fpr[i], tpr[i])
roc_auc[i] = roc_auc_score(y_test[:, i],y_score[:, i])
ax.plot(fpr[i],tpr[i],label="target=%s,auc=%s"%(i,roc_auc[i]))
ax.plot([0, 1], [0, 1], 'k--')
ax.set_xlabel("FPR")
ax.set_ylabel("TPR")
ax.set_title("ROC")
ax.legend(loc="best")
ax.set_xlim(0,1.1)
ax.set_ylim(0,1.1)
ax.grid()
plt.show()
if __name__=='__main__':
# test_accuracy_score() # 调用 test_accuracy_score
# test_precision_score() # 调用 test_precision_score
# test_recall_score() # 调用 test_recall_score
# test_f1_score() # 调用 test_f1_score
# test_fbeta_score() # 调用 test_fbeta_score
# test_classification_report() # 调用 test_classification_report
# test_confusion_matrix() # 调用 test_confusion_matrix
# test_precision_recall_curve() # 调用 test_precision_recall_curve
test_roc_auc_score() # 调用 test_roc_auc_score
- 如图：
