Python2.7：確保3D對象列表是唯一的

Question

我在Python中使用3D對象列表來組織我擁有的數據集。我注意到我的對象元素不是很獨特，即數組中一個對象內部的變量正在更新。下面顯示了一個說明我的問題的最小工作示例。

class myClass: 
     def __init__(self,ListA=[],ListB=[],ListCount=0): 
       self.ListA = ListA 
       self.ListB = ListB 
       self.ListCount = ListCount 

     def add_data(self,ElementA,ElementB): 
       self.ListA.append(ElementA) 
       self.ListB.append(ElementB) 
       self.ListCount = self.ListCount + 1 

     def check_data(self): 
       if(len(self.ListA) != self.ListCount): 
         print("Error: Unaccounted for Data in Object!") 
         print("Object has %d elements. Thinks it has %d"%(len(self.ListA),self.ListCount)) 

使用這個類定義的python代碼就像這樣。

import random 

ObjectArray = [[[myClass() for k in range(4)] for j in range(3)] for i in range(2)] 
#Print addresses of object array 
print("Addresses of the individual object elements in the 3D list ") 
for i in range(0,2): 
     for j in range(0,3): 
       for k in range(0,4): 
         print(ObjectArray[i][j][k]) 

#Loop over object array and fill each object with some data 
for i in range(0,2): 
     for j in range(0,3): 
       for k in range(0,4): 

         NumData = int(10*random.random()) 

         for m in range(0,NumData): 

           #Generate some junk data to insert into the list of this object 
           ListAData = int(10*random.random()) 
           ListBData = int(10*random.random()) 

           ObjectArray[i][j][k].check_data() 
           ObjectArray[i][j][k].add_data(ListAData,ListBData) 
           ObjectArray[i][j][k].check_data() 

我錯過了什麼？是否有可能在Python 2.7中使用3D對象列表？打印出來時，列表中的每個對象似乎都有一個唯一的內存地址。任何有識之士將不勝感激。

從該代碼輸出的樣品是：

Addresses of the individual object elements in the 3D list 
<__main__.myClass instance at 0x7fc59ad4ef80> <__main__.myClass 
instance at 0x7fc59ad635a8> <__main__.myClass instance at 
0x7fc59ad63248> <__main__.myClass instance at 0x7fc59ad63440> 
<__main__.myClass instance at 0x7fc59ad6d320> <__main__.myClass 
instance at 0x7fc59ad6d368> <__main__.myClass instance at 
0x7fc59ad6d3b0> <__main__.myClass instance at 0x7fc59ad6d3f8> 
<__main__.myClass instance at 0x7fc59ad6d488> <__main__.myClass 
instance at 0x7fc59ad6d4d0> <__main__.myClass instance at 
0x7fc59ad6d518> <__main__.myClass instance at 0x7fc59ad6d560> 
<__main__.myClass instance at 0x7fc59ad6d638> <__main__.myClass 
instance at 0x7fc59ad6d680> <__main__.myClass instance at 
0x7fc59ad6d6c8> <__main__.myClass instance at 0x7fc59ad6d710> 
<__main__.myClass instance at 0x7fc59ad6d7a0> <__main__.myClass 
instance at 0x7fc59ad6d7e8> <__main__.myClass instance at 
0x7fc59ad6d830> <__main__.myClass instance at 0x7fc59ad6d878> 
<__main__.myClass instance at 0x7fc59ad6d908> <__main__.myClass 
instance at 0x7fc59ad6d950> <__main__.myClass instance at 
0x7fc59ad6d998> <__main__.myClass instance at 0x7fc59ad6d9e0> 
Error: Unaccounted for Data in Object! Object has 4 elements. Thinks it has 0 
Error: Unaccounted for Data in Object! Object has 5 elements. Thinks it has 1 
Error: Unaccounted for Data in Object! Object has 5 elements. Thinks it has 1 
Error: Unaccounted for Data in Object! Object has 6 elements. Thinks it has 2 
Error: Unaccounted for Data in Object! Object has 6 elements. Thinks it has 2 
Error: Unaccounted for Data in Object! Object has 7 elements. Thinks it has 3 
Error: Unaccounted for Data in Object! Object has 7 elements. Thinks it has 3 

Answer 1

改變它

class myClass: 
    def __init__(self,ListA=None,ListB=None,ListCount=0): 
      self.ListA = [] if ListA is None else ListA 
      self.ListB = [] if ListB is None else ListB 
      self.ListCount = ListCount 

這將避免可變默認參數

考慮以下

class MyClass: 
    def __init__(self,a=[],b=None): 
     self.a = a 
     print "ID of a:",id(a) 
     if b is not None: 
      self.a.append(b) 

print MyClass(b=5).a 
print MyClass(b=6).a 
print MyClass(b=7).a 

注意，每個MyClass的具有獨特的存儲位置，但所有3個指向同一個數組（一個默認參數）