About the import path of a module in Python

Two days ago a colleague asked a Python question:

Why a python file in a directory references a Python file that does not have another sibling directory, but the parent record of the two directories can be referenced at runtime. At that time, the feeling has been the module and the mechanism of the package problem, back to turn over the book, found to refer to the problem of the path, record.

In Python, when we import the module, the system will go down to the Python reference path to find the module file, the reference path is specified during compilation or installation, can be modified in two places:

• Shell's pythonpath environment variable, the system will be found in the directory of this variable.
• Can be modified by Sys.path list in Python program

Asked by others, only to find me Python is the entry level, to learn more. Used in the past, are to use, do not think of the underlying mechanism behind, superficial understanding, or to summarize a bit more.

About the import path of a module in Python