python - 无法从同一包导入 python 模块

Question

我目前正在用 python 编写一个库。我有一个名为 Selectors 的包作为库的子目录。我正在尝试在包中实现一个新模块，但是当我尝试导入它时出现错误:

NameError: name '_RaceSelector__ResultSelector' is not defined

我的目录如下所示:

Selectors
│   ├── __init__.py
│   ├── __init__.pyc
│   ├── __pycache__
│   │   ├── SeasonSelector.cpython-38.pyc
│   │   ├── Selector.cpython-38.pyc
│   │   ├── __init__.cpython-38.pyc
│   │   ├── race_selector.cpython-38.pyc
│   │   ├── result_selector.cpython-38.pyc
│   │   └── season_selector.cpython-38.pyc
│   ├── race_selector.py
│   ├── race_selector.pyc
│   ├── result_selector.py
│   ├── result_selector.pyc
│   ├── season_selector.py
│   ├── season_selector.pyc
│   ├── selector.py
│   └── selector.pyc

我想使用race_selector.py中的模块，这是该文件:

from .selector import __Selector
from .result_selector import __ResultSelector

class RaceSelector(__Selector):

    data = []
    loaded_races = []
    header = []

    result_selector = __ResultSelector()

选择器.py

import os
import csv

class __Selector:
    def __init__(self, file_name):
        self.data_path = os.path.join(os.path.dirname(os.path.abspath(__file__)), '../data/' + file_name + '.csv')
        self.raw_data = self.load_data()
        self.data = self.get_data()

结果选择器.py

import os
from .selector import __Selector

class __ResultSelector(__Selector):
    def __init__(self):
        super().__init__('results')

我能够正常导入 selector 并按预期工作，但 result_selector 会产生错误。

谢谢

Answer 1

当您执行以下操作时:

result_selector = __ResultSelector()

Python 搜索 _RaceSelector__ResultSelector 因为有 2 个下划线。

如 PEP8 中所述:

If your class is intended to be subclassed, and you have attributes that you do not want subclasses to use, consider naming them with double leading underscores and no trailing underscores. This invokes Python's name mangling algorithm, where the name of the class is mangled into the attribute name. This helps avoid attribute name collisions should subclasses inadvertently contain attributes with the same name.