Python learning 10 -- engineering structure (package, module) & namespace & import module and variable &_ init_. py＆_ all_＆_ name_

1、 Engineering structure （ package 、 modular ）

Distinguish between directories and packages ：

If you have this document , It's just a bag ; If there is no , That's the catalog .

modular ：xxxx.py file

2、 Namespace

A variable with the same name as a global variable in a function becomes a local variable

To reference a global variable , The function must be modified

Local namespace ：

Global namespace ：


locals() read-only
globals() read-write

3、 stay python Import modules into the project

1）


2）
The module name you want to import is too long

names


There is another import method （ Dynamic import ）

It's fine too ：
from package import moudule
When this package When it comes to hierarchical packages , To write out the parent package .

4、 Import the variables

Import a variable from another module , It can also be nicknamed

The code of the imported module will also be executed

When importing multiple variables , It can be enclosed in brackets , Line break . So that we don't make a mistake .

It can also be used. * To import all variables

5、init.py

• The directory where the flag is located is a module package
• It's also a module in itself , It can also be executed like other modules
• Can be used to define what will be imported when fuzzy import
• When importing a package , Will execute _init_.py What's in it

6、all

• Put it in init Inside , It will mark the module in fuzzy import
• Put it under the common module , Identify a module , Which attributes are allowed to be imported into other modules （ Fuzzy import ）

7、name

Displays the name of the current module in the execution project , If the current program is running in this module , This module is called _main_

if name=="main" Generally refers to the entrance where the whole project starts to operate

Determine whether it is in this module , if , The output ……, otherwise , Output the name of this module