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 12:00:36 浏览: 58
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。
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