Python path-modules and packages

A. Module

1. Definition: Contains the Python definition and the declaration file, the file name is the module name plus the. py suffix.

Import loaded modules are divided into four categories:

Code written in 1.Python (. py file)

2. C or C + + extensions that have been compiled as shared libraries or DLLs

3. Package a set of modules

4. Built-in modules written and linked to the Python interpreter using C

2. Import Module Execution Process:

1. Execute the source file

2. Generate a global namespace for a source file

3. Get a module name at the current location, pointing to the resulting namespace of the source file.

3. Two ways to import modules:

Examples of 1.import import modules:

2.from... Import Module Use example:

Two ways to import comparison: 1:2 point to clearer, does not occur the confusion of file name space, 2:1 use more concise and convenient, without prefix.

3. Search Path of the module

Memory------"Built-in module-------" hdd (Sys.path)

Two. Package

Definition: The essence is a directory containing _init_.py files. It's a special module.

Relative imports of packages:

Absolute import of packages:

Python path-modules and packages