ValueError：可变默认值＆lt; class＆＃x27; dict＆＃x27;＆gt;对于场标头，不允许：使用Default_factory

发布于 2025-02-07 10:22:17 字数 894 浏览 1 评论 0原文

我正在尝试使用新的Python的功能（Dataclasses）。我正在尝试初始化变量，并且会遇到错误：

raise ValueError(f'mutable default {type(f.default)} for field '
ValueError: mutable default <class 'dict'> for field headers is not allowed: use default_factory

我的代码：

@dataclass
class Application():
    __config = ConfigParser()
    __config.read('mydb.ini')
    __host: str = __config.get('db','dbhost')
    __user: str = __config.get('db','dbuser')
    __password: str = __config.get('db','dbpw')
    __database: str = __config.get('db','database')
    url: str = "https://xxxx.domain.com/"
    headers: str = {'X-ApiKeys':'accessKey=xxxxxxx;secretKey=xxxxx','Content-Type': 'application/json'}



def main(self):
    print(self.__host,self.__user,self.__password, self.__database)
   


app = Application()
if __name__=="__main__":
    app.main()

初始化字典的正确方法是什么？

原文

I am trying to get used with new python's features (dataclasses). I am trying to initialize variables and I get error:

raise ValueError(f'mutable default {type(f.default)} for field '
ValueError: mutable default <class 'dict'> for field headers is not allowed: use default_factory

My code:

@dataclass
class Application():
    __config = ConfigParser()
    __config.read('mydb.ini')
    __host: str = __config.get('db','dbhost')
    __user: str = __config.get('db','dbuser')
    __password: str = __config.get('db','dbpw')
    __database: str = __config.get('db','database')
    url: str = "https://xxxx.domain.com/"
    headers: str = {'X-ApiKeys':'accessKey=xxxxxxx;secretKey=xxxxx','Content-Type': 'application/json'}



def main(self):
    print(self.__host,self.__user,self.__password, self.__database)
   


app = Application()
if __name__=="__main__":
    app.main()

What's the proper way to initialize dictionaries?

分享到QQ

分享到微博

如果你对这篇内容有疑问，欢迎到本站社区发帖提问参与讨论，获取更多帮助，或者扫码二维码加入 Web 技术交流群。

发布评论

需要登录才能够评论，你可以免费注册一个本站的账号。

半城柳色半声笛 2025-02-14 10:22:17

数据级有一些有用的东西来定义复杂字段。您需要的一个称为 field 。这个有参数default_factory需要接收可召唤，并且在某些地方lambda可以进行救援。因此，使用上面的代码看起来像（仅与DICE的一部分）：

from dataclasses import field
from typing import Dict

@dataclass
class Application():
    ...
    headers: Dict[str, str] = field(
        default_factory=lambda: {'X-ApiKeys':'accessKey=xxxxxxx;secretKey=xxxxx','Content-Type': 'application/json'}
    )

Dataclasses have a few useful things for defining complex fields. The one that you need is called field. This one has the argument default_factory that needs to receive callable, and there is where lambda comes to the rescue. So using this above, code that will work looks like (just part with dict):

from dataclasses import field
from typing import Dict

@dataclass
class Application():
    ...
    headers: Dict[str, str] = field(
        default_factory=lambda: {'X-ApiKeys':'accessKey=xxxxxxx;secretKey=xxxxx','Content-Type': 'application/json'}
    )

回复收藏 0 原文

~没有更多了~