old_contents: import numpy as np
  
  arr1 = np.array([[1,2],[3,4]])
  arr2 = np.array([[5,6],[7,8]])
  arr3 = np.array([[1,2],[3,4],[5,6]])
  arr4 = np.array([7,8])
  
  # 列出矩陣的維度
  # print(arr1.shape)
  # print(arr1.shape[0])
  
  # 矩陣乘積
  # print(np.dot(arr1,arr2)) 
  print(np.dot(arr3,arr4))
  
  
  # print(arr1*arr2)
  
  
new_contents: import numpy as np
  
  arr1 = np.array([[1,2],[3,4]])
  arr2 = np.array([[5,6],[7,8]])
  arr3 = np.array([[1,2],[3,4],[5,6]])
  arr4 = np.array([7,8])
  
  # 列出矩陣的維度
  # print(arr1.shape)
  # print(arr1.shape[0])
  
  # 矩陣乘積
  # print(np.dot(arr1,arr2)) 
  print(np.dot(arr3,arr4)) 
  
  print(1*7+2*7)
  
  
  # print(arr1*arr2)
  
  
subject: Create 3 layer nt sample