Numpy 的使用

import numpy as np

### mean()函数功能：求取均值 矩阵y_pred 减去 矩阵 y_true 平方后求取均值
np.mean((y_pred - y_true)**2)

### 生成矩阵
arr1d = np.array([1, 2, 3, 4])
print(arr1d) # 输出: [1 2 3 4]

arr2d = np.array([[1, 2, 3], [4, 5, 6]])
print(arr2d) # 输出: [[1 2 3] [4 5 6]]