Python underline in practical applications

The Python programming language is a novel application language for programmers. However, it is easy to grasp the application of this language. We will introduce some basic application methods of this language here, such as the Python underline application.

• Brief introduction to the basic application method of calling Python scripts
• Python Class correct application code example analysis
• Python Helloworld simple implementation
• How to install Python
• Common Python application skills Content Analysis

Before learning about the Python underline, let's take a look at what features this language brings to us.

Simple ---- Python is a language that represents the simple ideology. Reading a good Python program is like reading English, although the English requirements are very strict! The essence of this pseudo-code in Python is one of its biggest advantages. It enables you to focus on solving problems rather than understanding the language itself.

Easy to learn ---- as you will see soon, Python is extremely easy to use. As mentioned above, Python has extremely simple syntax.

Free and open-source ---- Python is one of FLOSS free/open source software. Simply put, you can freely publish copies of the software, read its source code, make changes to it, and use part of it in new free software. FLOSS is based on the concept of a group sharing knowledge. This is one of the reasons why Python is so excellent-it was created and often improved by a group of people who want to see a better Python.

High-level Language-when writing a program in Python, you do not need to consider the underlying details such as how to manage the memory used by your program.

Portability-because of its open source nature, Python has been transplanted on many platforms and changed to make it work on different platforms ). If you are careful not to use system-dependent features, all your Python programs can run on any of the following platforms without modification. These platforms include Linux, Windows, FreeBSD, Macintosh, Solaris, OS/2, Amiga, AROS, AS/400, BeOS, OS/390, z/OS, Palm OS, QNX, VMS, Psion, Acom risc OS, VxWorks, PlayStation, Sharp Zaurus, Windows CE, and even PocketPC and Symbian!

Explanatory ---- this requires some explanation. A program written in a compiled language such as C or C ++ can be converted from the source file C or C ++ to the binary code of the language used by your computer, 0 and 1 ). This process is completed by the compiler and different tags and options. When you run your program, the connection/reprinter software copies your program from the hard disk to the memory and runs it. Programs Written in Python do not need to be compiled into binary code. You can run the program directly from the source code. Inside the computer, the Python interpreter converts the source code into an intermediate form called bytecode, and then translates it into the machine language used by the computer and runs it. In fact, because you no longer need to worry about how to compile the program, how to ensure that the correct library is reprinted, and so on, all of this makes Python easier to use. Because you only need to copy your Python program to another computer, it can work, which makes your Python program easier to transplant.

Object-oriented-Python supports both process-oriented and object-oriented programming. In a "process-oriented" language, a program is built by a process or a function that is only reusable code. In the "Object-Oriented" language, a program is built by combining data and functions. Compared with other major languages such as C ++ and Java, Python implements object-oriented programming in a very powerful and simple way.

Scalability-if you need a piece of key code to run faster or want some algorithms not to be made public, you can write some of your programs in C or C ++, then use them in your Python program.

Embedding-you can embed Python into your C/C ++ program to provide script functions to your program users.

A wide range of libraries-the Python standard library is indeed huge. It can help you deal with various jobs, including regular expressions, document generation, unit testing, threads, databases, web browsers, CGI, FTP, e-mail, XML, XML-RPC, HTML, WAV Files, password systems, and GUI graphics user Interface), Tk, and other system-related operations. Remember, all these functions are available as long as Python is installed. This is called Python's "full functionality" concept. In addition to the standard library, there are many other high-quality libraries, such as wxPython, Twisted, and Python image libraries.

Summary-Python is indeed a wonderful and powerful language. It combines high performance with features that make programming simple and interesting.

Use the Python underline as the prefix and suffix of the variable to specify special variables.

_ Xxx cannot be imported using 'from module import *'

_ Xxx _ system definition name

_ Private variable name in xxx class

Core style: Avoid using underscores as the start of variable names.

Because the Python underline has a special meaning for the interpreter and is the symbol used by the built-in identifier, we recommend that programmers avoid using the underline as the start of the variable name. Generally, variable name_xxx is considered as "private" and cannot be used outside the module or class. When the variable is private, it is a good habit to use _ xxx to represent the variable. Because the variable name _ xxx _ has a special meaning for Python, this naming style should be avoided for common variables.

The member variables starting with "single underline" are called protection variables, meaning that only class objects and subclass objects can access these variables themselves;
"Double underline" begins with a private member, which means that only the class object can access the data, and even the subclass object cannot access the data.

_ Foo with a single underscore (_ foo) indicates class attributes that cannot be directly accessed. The class must be accessed through the interface provided by the class, and cannot be imported using "from xxx import; _ foo) starting with a double underline represents a private member of the class; _ foo _) Starting with and ending with a double underline represents a special identifier for special methods in python, for example, _ init _) indicates the class constructor.