One, the package
A package is made up of a series of modules, which are simply said to be a. py file. For example, there is now a mathematical function group that can calculate addition, subtraction, multiplication, division, power operations, and so on, assuming that these functions are divided into several modules, a module is a. py file. The concept of a package is formed by these different modules, which form a functional group of mathematical operations.
- A package must contain a __init__.py file.
- when a package is called, the __init__.py file is run first .
Second, the level of the package
Packages can be nested, and a package can contain several sub-packages. For example, a package contains B and C packages, and the B package contains D and e packets, then the module in a package can identify the contents of B and C packages. :
Python series (i) Package and module