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 18:59:07 浏览: 67
好的,我可以帮你回答这个问题。不过,在开始之前,我需要先确认一些信息。你是否已经准备好了乳腺癌数据集?如果没有,你可以在sklearn库中找到这个数据集。同时,你需要确保已经安装了matplotlib库和sklearn库,这两个库是用来画PR曲线和ROC曲线以及实现逻辑回归分类方法的。
假设你已经准备好了数据,那么下面就是步骤:
1. 导入需要的库
```python
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, average_precision_score
import matplotlib.pyplot as plt
```
2. 加载数据集并进行数据拆分
```python
data = load_breast_cancer()
X_train, X_test, y_train, y_test = train_test_split(data.data, data.target, test_size=0.3, random_state=1)
```
3. 定义逻辑回归模型并进行训练
```python
model = LogisticRegression()
model.fit(X_train, y_train)
```
4. 预测测试集数据并计算性能评价指标
```python
y_pred = model.predict(X_test)
y_score = model.decision_function(X_test)
precision, recall, _ = precision_recall_curve(y_test, y_score)
average_precision = average_precision_score(y_test, y_score)
fpr, tpr, _ = roc_curve(y_test, y_score)
roc_auc = auc(fpr, tpr)
```
5. 绘制PR曲线和ROC曲线
```python
fig, ax = plt.subplots(1, 2, figsize=(12, 6))
ax[0].step(recall, precision, color='b', alpha=0.2, where='post')
ax[0].fill_between(recall, precision, step='post', alpha=0.2, color='b')
ax[0].set_xlabel('Recall')
ax[0].set_ylabel('Precision')
ax[0].set_ylim([0.0, 1.05])
ax[0].set_xlim([0.0, 1.0])
ax[0].set_title('2-class Precision-Recall curve: AP={0:0.2f}'.format(average_precision))
ax[1].plot(fpr, tpr, color='darkorange', lw=2, label='ROC curve (area = %0.2f)' % roc_auc)
ax[1].plot([0, 1], [0, 1], color='navy', lw=2, linestyle='--')
ax[1].set_xlim([0.0, 1.0])
ax[1].set_ylim([0.0, 1.05])
ax[1].set_xlabel('False Positive Rate')
ax[1].set_ylabel('True Positive Rate')
ax[1].set_title('Receiver operating characteristic')
ax[1].legend(loc="lower right")
plt.show()
```
这样就完成了对乳腺癌数据的分类,并计算了平均精确率和AUC,同时绘制了PR曲线和ROC曲线。
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