Question

我做了两个名为House and Window的课程。然后，我列出了包含四个房屋的清单。 House的每个实例都有一个Windows列表。我正在尝试遍历每个房子的窗户并打印它的ID。但是，我似乎得到了一些奇怪的结果：S我非常感谢任何帮助。

#!/usr/bin/env python

# Minimal house class
class House:
    ID = ""
    window_list = []

# Minimal window class
class Window:
    ID = ""

# List of houses
house_list = []

# Number of windows to build into each of the four houses
windows_per_house = [1, 3, 2, 1]

# Build the houses
for new_house in range(0, len(windows_per_house)):

    # Append the new house to the house list
    house_list.append(House())

    # Give the new house an ID
    house_list[new_house].ID = str(new_house)  

    # For each new house build some windows
    for new_window in range(0, windows_per_house[new_house]):

        # Append window to house's window list
        house_list[new_house].window_list.append(Window())

        # Give the window an ID
        house_list[new_house].window_list[new_window].ID = str(new_window)

#Iterate through the windows of each house, printing house and window IDs.
for house in house_list:
    print "House: " + house.ID

    for window in house.window_list:
        print "   Window: " + window.ID

####################
# Desired output:
#
# House: 0
#    Window: 0
# House: 1
#    Window: 0
#    Window: 1
#    Window: 2
# House: 2
#    Window: 0
#    Window: 1
# House: 3
#    Window: 0  
####################

Answer 1

目前您正在使用class attributes instead of instance attributes。尝试将类定义更改为以下内容：

class House:
    def __init__(self):
        self.ID = ""
        self.window_list = []

class Window:
    def __init__(self):
        self.ID = ""

您的代码现在的方式House的所有实例共享相同的window_list。

Answer 2

这是更新的代码。

# Minimal house class
class House:
    def __init__(self, id):
        self.ID = id
        self.window_list = []

# Minimal window class
class Window:
    ID = ""

# List of houses
house_list = []

# Number of windows to build into each of the for houses
windows_per_house = [1, 3, 2, 1]

# Build the houses
for new_house in range(len(windows_per_house)):

    # Append the new house to the house list
    house_list.append(House(str(new_house)))

    # For each new house build some windows
    for new_window in range(windows_per_house[new_house]):

        # Append window to house's window list
        house_list[new_house].window_list.append(Window())

        # Give the window an ID
        house_list[new_house].window_list[new_window].ID = str(new_window)

#Iterate through the windows of each house, printing house and window IDs.
for house in house_list:
    print "House: " + house.ID

    for window in house.window_list:
        print "   Window: " + window.ID

实际问题是window_list属性是可变的，所以当不同的实例使用它时，它们最终会共享同一个属性。通过将window_list移动到__init__，每个实例都有自己的。

Answer 3

除了一些缩进错误之外，您还要将ID和window_list分配给类，而不是实例。

你想要像

这样的东西

class House():
    def __init__(self, ID):
        self.ID = ID
        self.window_list = []

等

然后，您可以执行house_list.append(House(str(newHouse)))等等。

Python：遍历对象列表中的对象列表

4 个答案: