Python中的模块和包概念介绍
模块概述
如果说模块是按照逻辑来组织 Python 代码的方法, 那么文件便是物理层上组织模块的方法。
因此, **一个文件被看作是一个独立模块, 一个模块也可以被看作是一个文件。 模块的文件名就是模
块的名字加上扩展名 .py 。 与其它可以导入类(class)的语言不同,在 Python 中你导入的是模块或模块属性**。
模块名称空间
一个名称空间就是一个名称到对象的关系映射.
导入模块
导入模块整体(import)
方式一
import module1
import module2
...
import moduleN
方式二
import module1[, module2[,... moduleN]]
导入模块属性(from … import …)
调用 from-import 可以把名字导入当前的名称空间里去, 这意味着你不需要使用属性/句点属性标识来访问模块的标识符。 例如, 你需要访问模块 module 中的 var 名字是这样被导入的:
from module import name1[, name2[,… nameN]]
模块或属性导入后重命名
import ... as ...
from ... import ... as ...
包
包是一个有层次的文件目录结构, 模块对应单个文件,包对应一个目录.与 类 和 模 块 相 同 , 包 也 使 用 句 点 属 性 标 识 来 访 问 他 们 的 元 素。使 用 标 准 的 import 和from-import 语句导入包中的模块。

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