调用sklearn库实现对乳腺癌数据的分类,采用逻辑回归分类方法,并计算以下性能评价指标:平均精确率、AUC,并绘制PR曲线与ROC曲线。
时间: 2024-02-24 08:00:36 浏览: 66
Breast_Cancer_Classification:利用逻辑回归和神经网络模型基于数字化活检图像将乳腺癌肿瘤分类为恶性或良性
好的,以下是对乳腺癌数据的分类的示例代码,包括逻辑回归分类方法、性能评价指标计算和绘制PR曲线与ROC曲线的过程。
首先,我们需要导入需要的库和数据集:
```python
import numpy as np
import pandas as pd
import matplotlib.pyplot as plt
from sklearn.datasets import load_breast_cancer
from sklearn.model_selection import train_test_split
from sklearn.linear_model import LogisticRegression
from sklearn.metrics import precision_recall_curve, roc_curve, auc
# 导入数据集
cancer = load_breast_cancer()
X = cancer.data
y = cancer.target
```
然后,我们将数据集分为训练集和测试集:
```python
# 将数据集分为训练集和测试集
X_train, X_test, y_train, y_test = train_test_split(X, y, test_size=0.3, random_state=42)
```
接下来,我们使用逻辑回归模型对数据进行分类:
```python
# 创建逻辑回归模型并拟合训练集
lr = LogisticRegression()
lr.fit(X_train, y_train)
# 在测试集上预测
y_pred = lr.predict(X_test)
```
然后,我们计算平均精确率和AUC:
```python
# 计算平均精确率
precision, recall, _ = precision_recall_curve(y_test, lr.predict_proba(X_test)[:, 1])
average_precision = np.mean(precision)
# 计算AUC
fpr, tpr, _ = roc_curve(y_test, lr.predict_proba(X_test)[:, 1])
roc_auc = auc(fpr, tpr)
```
最后,我们绘制PR曲线和ROC曲线:
```python
# 绘制PR曲线
plt.step(recall, precision, color='b', alpha=0.2, where='post')
plt.fill_between(recall, precision, step='post', alpha=0.2, color='b')
plt.xlabel('Recall')
plt.ylabel('Precision')
plt.ylim([0.0, 1.05])
plt.xlim([0.0, 1.0])
plt.title('Precision-Recall curve: AP={0:0.2f}'.format(average_precision))
plt.show()
# 绘制ROC曲线
plt.plot(fpr, tpr, color='darkorange', lw=2, label='ROC curve (area = %0.2f)' % roc_auc)
plt.plot([0, 1], [0, 1], color='navy', lw=2, linestyle='--')
plt.xlim([0.0, 1.0])
plt.ylim([0.0, 1.05])
plt.xlabel('False Positive Rate')
plt.ylabel('True Positive Rate')
plt.title('Receiver operating characteristic')
plt.legend(loc="lower right")
plt.show()
```
完整代码如下:
```python
import numpy as np
import pandas as pd
import matplotlib.pyplot as plt
from sklearn.datasets import load_breast_cancer
from sklearn.model_selection import train_test_split
from sklearn.linear_model import LogisticRegression
from sklearn.metrics import precision_recall_curve, roc_curve, auc
# 导入数据集
cancer = load_breast_cancer()
X = cancer.data
y = cancer.target
# 将数据集分为训练集和测试集
X_train, X_test, y_train, y_test = train_test_split(X, y, test_size=0.3, random_state=42)
# 创建逻辑回归模型并拟合训练集
lr = LogisticRegression()
lr.fit(X_train, y_train)
# 在测试集上预测
y_pred = lr.predict(X_test)
# 计算平均精确率
precision, recall, _ = precision_recall_curve(y_test, lr.predict_proba(X_test)[:, 1])
average_precision = np.mean(precision)
# 计算AUC
fpr, tpr, _ = roc_curve(y_test, lr.predict_proba(X_test)[:, 1])
roc_auc = auc(fpr, tpr)
# 绘制PR曲线
plt.step(recall, precision, color='b', alpha=0.2, where='post')
plt.fill_between(recall, precision, step='post', alpha=0.2, color='b')
plt.xlabel('Recall')
plt.ylabel('Precision')
plt.ylim([0.0, 1.05])
plt.xlim([0.0, 1.0])
plt.title('Precision-Recall curve: AP={0:0.2f}'.format(average_precision))
plt.show()
# 绘制ROC曲线
plt.plot(fpr, tpr, color='darkorange', lw=2, label='ROC curve (area = %0.2f)' % roc_auc)
plt.plot([0, 1], [0, 1], color='navy', lw=2, linestyle='--')
plt.xlim([0.0, 1.0])
plt.ylim([0.0, 1.05])
plt.xlabel('False Positive Rate')
plt.ylabel('True Positive Rate')
plt.title('Receiver operating characteristic')
plt.legend(loc="lower right")
plt.show()
```
希望这个示例代码能够帮助你实现对乳腺癌数据的分类,并计算性能评价指标和绘制PR曲线和ROC曲线。如果你还有其他问题或需要更多帮助,请随时问我。
阅读全文