CodeMan | spring-dbutil-jsp-web 代码生成项目

Whenever you import a module, Python creates a module object and stores it in the sys.modules dictionary. Subsequent imports of that same module will reuse the module object from sys.modules. Additionally, each time you import a submodule, the attribute is added to the parent module object.

There's one instance of sys.modules for a given Python process, and therefore in general there's only one instance of every module per Python process. It means that if you have access to a module object, you also have access to its submodules that have been imported anywhere within the current process.

In this particular case, import package runs package/__init__.py, which imports package.mod1, which imports package.mod2. As a result, mod1 and mod2 are added to the "shared" parent module object, and you can access them.