这只是为了“学习的乐趣”。我完全是从书籍和教程中自学的，而且对编程还是很陌生。我正在尝试探索从列表中创建对象的概念。这是我所拥有的：
class Obj: # Creates my objects
def __init__(self, x):
self.name = x
print('You have created a new object:', self.name)
objList = []
choice = 'y'
while choice != 'n': # Loop that runs until user chooses, 'n' to quit
for i in objList:
print(i) # Iterates through the list showing all of the objects added
for i in objList:
if Obj(i):
print(i, 'has already been created.') # Checks for existance of object, if so skips creation
else:
createObj = Obj(i) # Creates object if it doesn't exist
choice = input('Add object? (y / n): ')
if choice == 'y':
newObject = input('Name of object to add: ')
if newObject in objList: # Checks for existance of user enrty in list
print(newObject, 'already exists.') # Skips .append if item already in list
else:
objList.append(newObject) # Adds entry if not already in list
print('Goodbye!')
当我运行它时，我得到：
Add object? (y / n): y
Name of object to add: apple
apple
You have created a new object: apple # At this point, everything is correct
apple has already been created. # Why is it giving me both conditions for my "if" statement?
Add object? (y / n): y
Name of object to add: pear
apple
pear
You have created a new object: apple # Was not intending to re-create this object
apple has already been created.
You have created a new object: pear # Only this one should be created at this point
pear has already been created. # Huh???
Add object? (y / n): n
Goodbye!
我已经做了一些研究并阅读了几条关于创建 dict 来做我想做的事情的评论。我已经构建了一个使用 dict 执行此操作的程序，但出于学习目的，我试图了解这是否可以通过创建对象来完成。似乎一切正常，除了当程序通过遍历列表来检查对象的存在时，它会失败。
然后我这样做了：
>>> Obj('dog')
You have created a new object: dog
<__main__.Obj object at 0x02F54B50>
>>> if Obj('dog'):
print('exists')
You have created a new object: dog
exists
这让我想到了一个理论。当我输入“if”语句时，它是否创建了一个名为“dog”的对象的新实例？如果是这样，我如何检查对象的存在？如果我将对象存储在变量中，我的顶部片段中的循环不会在每次迭代时覆盖变量吗？我的“打印”语句是因为对象存在还是因为它的下一行代码而运行？抱歉我的问题太长了，但如果我提供更好的信息，我相信我可以得到更好的答案。