python - Python 中 "__package__"属性的用途是什么？

Question

我只想知道__package__ 到底是什么意思？在官方文档中没有找到任何解释，即使在 SO 上也是如此。

如果你能提供一些例子，我会很高兴。

Answer 1

见 PEP 366和 import system reference documentation :

The major proposed change is the introduction of a new module level attribute, __package__. When it is present, relative imports will be based on this attribute rather than the module __name__ attribute.

和

• The module’s __package__ attribute should be set. Its value must be a string, but it can be the same value as its __name__. If the attribute is set to None or is missing, the import system will fill it in with a more appropriate value. When the module is a package, its __package__ value should be set to its __name__. When the module is not a package, __package__ should be set to the empty string for top-level modules, or for submodules, to the parent package’s name. See PEP 366 for further details.

因此，对于位于 foo/bar/baz.py 中的模块，__name__ 设置为 foo.bar.baz，并且__package__ 设置为 foo.bar，而 foo/bar/__init__.py 将具有 foo.bar __name__ 和 __package__ 属性。