用python解决,在西瓜数据集3.0(data)及其它自选数据集上用留一法进行训练和测试,观察线性支持向量机、非线性支持向量机两个模型的支持向量的差异及测试结果。, 给出留一法估计的查准率、查全率及F1值。
时间: 2024-12-22 07:13:01 浏览: 12
在Python中使用sklearn库及其提供的数据集如西瓜数据集(也可以自己导入其他数据集)进行留一法(Leave-One-Out Cross Validation,LOOCV)下的线性和非线性支持向量机(SVM)比较,你可以按照以下步骤操作:
1. **加载数据**:
导入所需的库,例如`numpy`, `pandas`, `matplotlib`, `sklearn`等,并读取数据集,将其分为特征和标签。
```python
import numpy as np
import pandas as pd
from sklearn import datasets
from sklearn.model_selection import LeaveOneOut
from sklearn.svm import LinearSVC, SVC
from sklearn.metrics import accuracy_score, precision_score, recall_score, f1_score
# 加载西瓜数据集或者其他数据集
if 'data' in locals():
X = data['features']
y = data['labels']
else:
西瓜_data = datasets.load西瓜()
X, y =西瓜_data.data,西瓜_data.target
```
2. **创建训练和测试函数**:
使用`LeaveOneOut`交叉验证,对每个样本进行一次训练和预测。
```python
def train_and_test(model, X, y):
loo = LeaveOneOut()
scores = []
for train_index, test_index in loo.split(X):
X_train, X_test = X[train_index], X[test_index]
y_train, y_test = y[train_index], y[test_index]
model.fit(X_train, y_train)
predictions = model.predict(X_test)
score = (accuracy_score(y_test, predictions),
precision_score(y_test, predictions, average='weighted'),
recall_score(y_test, predictions, average='weighted'),
f1_score(y_test, predictions, average='weighted'))
scores.append(score)
return scores
# 线性SVM
linear_svm = LinearSVC()
linear_scores = train_and_test(linear_svm, X, y)
# 非线性SVM(如RBF kernel)
non_linear_svm = SVC(kernel='rbf')
non_linear_scores = train_and_test(non_linear_svm, X, y)
```
3. **分析结果**:
计算并比较线性和非线性SVM的查准率(Accuracy)、查全率(Precision)、F1值。通常,你会看到非线性SVM在某些情况下可能会有较高的准确率或F1分数,因为它能更好地捕捉到数据的复杂模式。
```python
print("Linear SVM Results:")
for metric_name in ['Accuracy', 'Precision', 'Recall', 'F1']:
avg_linear_score = sum([score[metric_name] for score in linear_scores]) / len(linear_scores)
print(f"{metric_name}: {avg_linear_score}")
print("\nNon-Linear SVM Results:")
for metric_name in ['Accuracy', 'Precision', 'Recall', 'F1']:
avg_non_linear_score = sum([score[metric_name] for score in non_linear_scores]) / len(non_linear_scores)
print(f"{metric_name}: {avg_non_linear_score}")
```
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