采用Python编程语言自己实现一个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: 2024-05-06 16:15:48 浏览: 84
好的,下面是实现步骤。
首先,我们需要加载鸢尾花数据集。在Python中,我们可以使用scikit-learn库的load_iris函数来加载数据集。代码如下:
```python
from sklearn.datasets import load_iris
iris = load_iris()
X = iris.data
y = iris.target
```
接下来,我们将数据集分成5个部分,每个部分包含数据集的1/5。我们将使用NumPy库的array_split函数来实现。代码如下:
```python
import numpy as np
X_folds = np.array_split(X, 5)
y_folds = np.array_split(y, 5)
```
然后,我们将实现逻辑回归分类器。在Python中,我们可以使用scikit-learn库的LogisticRegression类来实现。代码如下:
```python
from sklearn.linear_model import LogisticRegression
classifier = LogisticRegression()
```
接下来,我们将使用5折交叉验证方法,来测试我们的逻辑回归分类器的准确性。代码如下:
```python
scores = []
for i in range(5):
X_train = list(X_folds)
X_test = X_train.pop(i)
X_train = np.concatenate(X_train)
y_train = list(y_folds)
y_test = y_train.pop(i)
y_train = np.concatenate(y_train)
classifier.fit(X_train, y_train)
score = classifier.score(X_test, y_test)
scores.append(score)
print(scores)
```
最后,我们可以计算平均分数,并输出结果。代码如下:
```python
print("Average score: ", sum(scores)/len(scores))
```
完整代码如下:
```python
from sklearn.datasets import load_iris
from sklearn.linear_model import LogisticRegression
import numpy as np
iris = load_iris()
X = iris.data
y = iris.target
X_folds = np.array_split(X, 5)
y_folds = np.array_split(y, 5)
classifier = LogisticRegression()
scores = []
for i in range(5):
X_train = list(X_folds)
X_test = X_train.pop(i)
X_train = np.concatenate(X_train)
y_train = list(y_folds)
y_test = y_train.pop(i)
y_train = np.concatenate(y_train)
classifier.fit(X_train, y_train)
score = classifier.score(X_test, y_test)
scores.append(score)
print(scores)
print("Average score: ", sum(scores)/len(scores))
```
希望对你有所帮助!
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