python 线性回归代码

以下是一个简单的Python线性回归代码示例：

import numpy as np
import matplotlib.pyplot as plt

# 输入数据
X = np.array([1, 2, 3, 4, 5])
Y = np.array([5, 7, 9, 11, 13])

# 均值
x_mean = np.mean(X)
y_mean = np.mean(Y)

# 总数据个数
n = len(X)

# 使用公式计算斜率和截距
numerator = 0
denominator = 0
for i in range(n):
    numerator += (X[i] - x_mean) * (Y[i] - y_mean)
    denominator += (X[i] - x_mean) ** 2
slope = numerator / denominator
intercept = y_mean - (slope * x_mean)

# 输出结果
print("斜率:", slope)
print("截距:", intercept)

# 绘制图像
plt.scatter(X, Y)
plt.plot(X, slope * X + intercept, 'r')
plt.show()

这个代码计算输入数据的线性回归，并绘制了一个散点图和回归线。