Python杂谈

• Ⅰ.Object
• Ⅱ. Module and Package
  • 1. What is Module?
  • 2. Usage of Module
    • Creation
    • Import
      • import and from
      • Import Happen Only Once
      • import and from Are Assignments
      • Module Search Path
    • Use
  • 3. Move on to Packages
• Ⅲ. Scope (Namespace)

Ⅰ.Object

• Object表示内存实体，Variable仅仅是该内存实体的一个Reference，如下图所示：

a = 3

• 类型信息被封装在Object中而非Variable中，Object中存在type dessgnator字段；
• Object的生命周期由Python的垃圾回收机制处理，Object中存在reference counter字段；
• Object的类型分为mutable (e.g. list, dict, set etc.)和immutable (e.g. built-in types etc.)；

Ⅱ. Module and Package

1. What is Module?

A Python program consisits of one main top-level file and zero or more modules.

A Python module is the highest-level program organization unit, which packages program code and data for reuse, and provides self-contained namespaces that minimize variable name clashes across your programs.

Python Module的优点

• 模块化编程；
• 管理命名空间(namespace)；

2. Usage of Module

Creation

A python module is just a python file.

Import

import and from

Import Happen Only Once

import and from Are Assignments

Module Search Path

Use

3. Move on to Packages

Ⅲ. Scope (Namespace)

TODO