Python中列表的問題

我是python的新手，但我有很多C++，Java和.NET的經驗。我希望有人能夠解釋爲什麼這個示例程序的工作方式如何，以及如何將其改變爲以我希望的方式工作。Python中列表的問題

基本上，我試圖創建一個對象列表，並且列表中的每個對象都包含一個對象列表。最後，子列表都是相同的列表，而不是對其父類的實例唯一的。

class Obj1(object): 
    list_of_obj2 = [] 
    name = '' 

class Obj2(object): 
    name = '' 

list_of_obj1 = [] 

for i in range(2): 
    new_obj1 = Obj1() 
    new_obj1.name = "obj1_%s" % i 
    print "Creating Object1 named %s" % new_obj1.name 

    for j in range(2): 
     new_obj2 = Obj2() 
     new_obj2.name = "...obj2_%s_%s" % (i, j) 

     new_obj1.list_of_obj2.append(new_obj2) 
     print "...Added Object2 named %s to %s list" % (new_obj2.name, new_obj1.name) 

    list_of_obj1.append(new_obj1) 
    print "Added Object1 named %s to master list" % (new_obj1.name) 

print "" 

for obj in list_of_obj1: 
    print "%s has %s items in list" % (obj.name, len(obj.list_of_obj2)) 
    for obj2 in obj.list_of_obj2: 
     print "...%s" % obj2.name

程序的輸出：

Creating Object1 named obj1_0 
...Added Object2 named ...obj2_0_0 to obj1_0 list 
...Added Object2 named ...obj2_0_1 to obj1_0 list 
Added Object1 named obj1_0 to master list 
Creating Object1 named obj1_1 
...Added Object2 named ...obj2_1_0 to obj1_1 list 
...Added Object2 named ...obj2_1_1 to obj1_1 list 
Added Object1 named obj1_1 to master list 

obj1_0 has 4 items in list 
......obj2_0_0 
......obj2_0_1 
......obj2_1_0 
......obj2_1_1 
obj1_1 has 4 items in list 
......obj2_0_0 
......obj2_0_1 
......obj2_1_0 
......obj2_1_1

爲什麼不兩OBJ1列出各有2個項目？有沒有更好的方法來實現這一點？

來源

2011-08-18 Ben

思考。如果你需要對象變量，你需要在__init__中定義它們，就像HYRY說的那樣。 – Bogdan

list_of_obj2是OBJ1的類屬性，如果你想實例屬性：你聲明的變量在Java中的靜態變量的

class Obj1(object): 
    def __init__(self): 
     self.list_of_obj2 = []

來源

2011-08-18 03:22:07 HYRY

Python中列表的問題

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