python--import method into the module

This article mainly introduces the details of the introduction of the Python import method into the module of the relevant data, in Python with import or From...import or from...import...as ... To import the corresponding module, the need for friends can refer to the following

An example of introducing a Python import method into a module

In Python with import or From...import or from...import...as ... To import the appropriate modules, using the same method as the C language include header file. In fact, it is to introduce some mature function libraries and mature methods to avoid repeating the wheel and improve the development speed.

The import method of Python can introduce the modules of the system, or we can introduce our own shared modules, which are very similar to PHP, but their specifics are not quite the same. Because PHP specifies the path to the file when it is introduced, it is not possible to write a file path in Python.

Here are a few things to consider about import:

Python contains the module method in subdirectories is relatively simple, the key is to be able to find the path to the module file inside the Sys.path.

Here are some examples of common situations:

(1) The main program and the module program are in the same directory:

such as the following program structure:

--src |--mod1.py–test1.py

If the module mod1 is imported in the program test1.py, the import mod1 or from MOD1 import * is used directly;

(2) The directory where the main program resides is the parent (or grandparent) directory of the directory where the module resides

such as the following program structure:

--src |--mod1.py |--mod2 |–mod2.py ' –test1.py

If you import the module mod2 in the program test1.py, you need to create an empty file init.py file in the Mod2 folder (you can also customize the Output module interface in the file); Then use the From MOD2.MOD2 Import * or import mod2.mod2.

(3) Main program import module in upper directory or other directory (peer)

such as the following program structure:

--src |--mod1.py |--mod2 |–mod2.py |–sub | --test2.py–test1.py

If you import modules Mod1 and MOD2 in the program test2.py. You first need to create a init.py file (same (2)) under MOD2, and you do not have to create the file under SRC. Then call the following method:

The following program execution methods are executed in the directory where the program files are located, such as test2.py is on CD sub; then execute Python test2.py

While test1.py is on CD src, then execute Python test1.py; The success of Python sub/test2.py in the SRC directory is not guaranteed.

Import sys sys.path.append ("..") Import mod1 Import mod2.mod2