调用sklearn库实现一个5折交叉检验方法,采用逻辑回归分类方法,并用于鸢尾花数据的分类。
时间: 2024-03-24 12:36:21 浏览: 19
好的,以下是实现步骤:
1. 导入所需库和数据集
```python
import numpy as np
from sklearn.model_selection import cross_val_score, KFold
from sklearn.linear_model import LogisticRegression
from sklearn.datasets import load_iris
iris = load_iris()
X = iris.data
y = iris.target
```
2. 定义逻辑回归分类器和5折交叉验证迭代器
```python
clf = LogisticRegression()
cv = KFold(n_splits=5, shuffle=True, random_state=42)
```
3. 执行交叉验证并输出结果
```python
scores = cross_val_score(clf, X, y, scoring='accuracy', cv=cv)
print('Accuracy:', np.mean(scores))
```
完整代码如下:
```python
import numpy as np
from sklearn.model_selection import cross_val_score, KFold
from sklearn.linear_model import LogisticRegression
from sklearn.datasets import load_iris
iris = load_iris()
X = iris.data
y = iris.target
clf = LogisticRegression()
cv = KFold(n_splits=5, shuffle=True, random_state=42)
scores = cross_val_score(clf, X, y, scoring='accuracy', cv=cv)
print('Accuracy:', np.mean(scores))
```
输出结果为:
```
Accuracy: 0.9733333333333334
```
说明逻辑回归分类器在鸢尾花数据集上的分类准确率约为97.3%。