簡單線性迴歸使用for循環只能用於Python

Question

我現在正在做線性迴歸分析。輸入變量是Size。輸出變量是Price。我將這組數據存儲在二維數組中。我知道使用NumPy很容易進行分析，但我的教授告訴我只用循環來執行迭代。 Formula of interation is shown as the picture in the hyperlink。因此，我決定下面的代碼來執行計算：

#Structure of array (Stored in float), with structure like this [Room, Price] 
array = [[4.0, 399.9], [5.0, 329.9], [6.0, 369.0]] 

#Set initial value 
theta_price = 0 
theta_room = 0 
stepsize = 0.01 
item = 3 

#Perform iterations 
for looping in range(0, 50): #Loop 50 times 
    for j in array[0]: #Call the value stored in array[0] 
     for k in array[1]: #Call the value stored in array[1] 
      theta_price_1 = theta_price - stepsize * (1/item) * (sum((theta_price + theta_room * int(j) - int(k)))#Perform iterations of theta 0 
      theta_room_1 = theta_room - stepsize * (1/item) * (sum((theta_price + t + theta_room * int(j) - int(k))*int(j)))#Perform iterations of theta 1 
      #Bring the new theta value to the next loop 
      theta_price = theta_price_1 
      theta_room = theta_room_1 
      print(theta_price,theta_room)#Print the result for every loop 

上面的代碼，錯誤消息在線路10沒有起作用的是：

'int' object is not iterable 

但是如果刪除的總和函數，它的工作原理計算結果不正確。因此，我知道它的sum函數和數組有一些問題，但我不知道如何解決它？

Answer 1

正如我在評論中提到的，sum應該適用於每次迭代中的所有元素，這就是批處理梯度下降的作用。因此，代碼應該是：

theta_price = 0 
theta_room = 0 
stepsize = 0.1 
item = 5 
#Perform iterations 
array = [ 
      [0,1,2,3,4], 
      [5,6,7,8,9], 
     ] 

for looping in range(0, 500): #Loop 50 times 
     theta_price = theta_price - stepsize * (1/item) * (sum([theta_price + theta_room * int(j) - int(k) for j, k in zip(array[0], array[1])]))#Perform iterations of theta 0 
     theta_room = theta_room - stepsize * (1/item) * (sum([(theta_price + theta_room * int(j) - int(k)) * int(j) for j, k in zip(array[0], array[1])]))#Perform iterations of theta 1 
     print(theta_price,theta_room)#Print the result for every loop 

經過500次迭代的5個測試數據，我可以得到結果：

4.999999614653767 1.0000001313279816 

這也在意料之中。