我有一个任务来制作一个名为“ project”的python包。在内部，我必须创建2个具有我事先指定的名称的单独文件。在每一个内部，我必须放置1个带有其参数和方法的类。到目前为止一切都很好。但这是问题所在-每个类都引用另一个类以使其正常工作（在任务描述中，为我提供了两个类的方法的名称，其中一些必须引用另一个类的对象，所以我当然使用了project.xxxx导入Xxxx）。
我有使用方法的类库-
add_user（用户：用户）
我具有方法的类User
get_book（作者：str，书名：str，days_to_return：int，库：Library）
[这里我了解了循环依赖问题。我为一些文章提供了解决方法-将这些内容合并到一个文件中或制作更多文件并重组代码。那是不行的-名为“ project”的程序包必须有2个带有提供名称的文件，每个文件中都有1个类，因为我必须将带有该程序包的zip文件提交到在线自动化系统进行测试。
我遇到的另一件事是将import语句放在一个文件的末尾。我在两个文件上都尝试了1个文件，但仍然出现ImportError。
将非常感谢您的帮助。
这里是头等舱：
from project.user import User
class Library:
def __init__(self):
self.user_records = []
self.books_available = {}
self.rented_books = {}
def add_user(self, user: User):
if user.username in [u.username for u in self.user_records]:
return f'User with id = {user.id} already registered in the library!'
self.user_records.append(user)
def remove_user(self, user: User):
if user.username not in [u.username for u in self.user_records]:
return 'We could not find such user to remove!'
for i, o in enumerate(self.user_records):
if o.username == user.username:
del self.user_records[i]
def change_username(self, user_id: int, new_username: str):
user = [u for u in self.user_records if u.id == user_id][0]
if not user:
return f'There is no user with id = {user_id}!'
if user.username == new_username:
return f'Please check again the provided username - it should be different than the username used so far!'
user.username = new_username
return f'Username successfully changed to: {new_username} for userid: {user_id}'
这是第二堂课：
from project.library import Library
class User:
def __init__(self, user_id: int, username: str):
self.books = []
self.id = user_id
self.username = username
def get_book(self, author: str, book_name: str, days_to_return: int, library: Library):
rented_books = [x for x in library.rented_books.values()]
if rented_books:
for x in rented_books:
if book_name in x:
days = x[book_name]
return f'he book "{book_name}" is already rented and will be available in' \
f' {days} days!'
if book_name in library.books_available[author]:
if self.username not in library.rented_books:
library.rented_books[self.username] = {}
library.rented_books[self.username].update({book_name: days_to_return})
library.books_available[author].remove(book_name)
self.books.append(book_name)
return f'{book_name} successfully rented for the next {days_to_return} days!'
def return_book(self, author:str, book_name:str, library: Library):
if book_name in self.books:
library.books_available[author].append(book_name)
library.rented_books[self.username].pop(book_name)
self.books.remove(book_name)
else:
return f"{self.username} doesn't have this book in his/her records!"
def info(self):
books = sorted(self.books, key=lambda x: x)
return ', '.join(books)
很好，您开始编写自己的代码并将其发布。
快速的答案是，您无需在Library类中添加类型提示。代替：
def add_user(self, user: User):
您可以写：
def add_user(self, user):
并删除导入语句（from project.user import User）
只需更改一下即可运行您的代码。我尝试这样做，例如：
library_of_congress = Library()
tom = User(user_id=1, username="tom")
library_of_congress.add_user(tom)
注意：您仍然需要执行一些其他步骤才能使其他功能正常工作：（但这超出了您的“循环依赖问题”的范围）
library_of_congress.books_available = { <put the book info here> }
tom.get_book( <put the correct arguments> )
等
希望这对您的剩余工作有帮助，祝您好运！您可以在此处阅读有关python中类型提示的更多信息：