机械学习案例python
时间: 2023-09-06 09:10:17 浏览: 31
以下是几个机器学习案例的 Python 代码示例:
1. 线性回归:
```python
import numpy as np
from sklearn.linear_model import LinearRegression
# 生成测试数据
X = np.array([[1], [2], [3], [4], [5]])
y = np.array([2.3, 4.5, 6.7, 8.9, 11.1])
# 初始化线性回归模型
model = LinearRegression()
# 拟合模型
model.fit(X, y)
# 预测
y_pred = model.predict(np.array([[6]]))
# 输出预测结果
print(y_pred)
```
2. 决策树分类:
```python
from sklearn.datasets import load_iris
from sklearn.tree import DecisionTreeClassifier
from sklearn.model_selection import train_test_split
# 加载数据集
iris = load_iris()
# 划分数据集
X_train, X_test, y_train, y_test = train_test_split(iris.data, iris.target, test_size=0.2)
# 初始化决策树模型
model = DecisionTreeClassifier()
# 拟合模型
model.fit(X_train, y_train)
# 预测
y_pred = model.predict(X_test)
# 输出准确率
print("Accuracy:", model.score(X_test, y_test))
```
3. K-Means 聚类:
```python
import numpy as np
from sklearn.cluster import KMeans
# 生成测试数据
X = np.array([[1, 2], [1, 4], [1, 0], [4, 2], [4, 4], [4, 0]])
# 初始化 K-Means 模型
model = KMeans(n_clusters=2)
# 拟合模型
model.fit(X)
# 预测
y_pred = model.predict(X)
# 输出聚类结果
print("Cluster labels:", y_pred)
```