A. What is a module?
py file is a module
classification:
System module (standard library)
Third-party modules (to download pip3 install the module name)
User-defined modules (py write their own file)
The role of the module?
Achieve the function reuse, to improve the efficiency of the code
The similar functions into a file, permanent preservation
Modules imported:
import...
from ...import ...
import did what?
Code into execution module
Create a namespace modules
The module introduced in the namespace variables, methods
Note the question:
The module will not be repeated introduced
Avoid circulation import
Module search order:
Directory where their
Built-in space
sys.path
sys.modules
After introduction of the dictionary stored in the module (the first module is a current path element)
sys.path module path list
as keywords
Aliases for complex modules, easy to use
if __name__ == '__main__': # main + tab shortcuts
When the script file to execute, the following code execution
When introduced into the module file, the following code is not performed
II. Package
definition:
__Init__.py file folder containing the files that package
A plurality of collection modules
Essentially Module
Absolute imports:
The directory where the executable file
Import module to be precise - no problem
import to invoke methods have to write back to write on
from aaa.ccc import c c.c()
from. The left must be a package, otherwise an error
Import content must not be behind the band.
Relative imports:
Executable file can not be introduced into the opposite
The current position .. parent directory ... on the directory
When you write the packet with others, not their own can use relative imports