Common built-in modules

modular What is it? ：     Suffix name .py

Module classification ：
         The creator ：
                 pathon Built-in module   Such as ,random、os、os.path
                 Third-party module —— Need to install
                 Custom module
The import module The way ：
                import Module name
                import Module name as Alias
                 Use only one method , use from Import     Such as ,from partial import functools

random library

math library

os library