python--Basic Knowledge

1.python is an interpretive, object-oriented, high-level programming language with dynamic semantics.

2.python advantages
★ founder Rating: Simple, elegant, clear
     ° is simply reflected in if your native language is English, writing a python script is like writing an article, very simple;
    ° elegant in python format, such as indentation to determine the code block, to avoid the programmer to do complex nesting; The
    ° clearly shows only one of the best options for solving the problem, while the Perl language is the most optimal solution for every problem. But not conducive to team collaboration;
★ There are powerful third-party library modules that need to implement a complex function that requires only the invocation of an existing library to quickly implement functionality. More than 20 years of development, all kinds of libraries have been completed
, such as: Mail library, crawler library ...
★ can be ported across platforms, Java has Java virtual machines, Python is the same;
★ is an object-oriented language;
★ is an extensible language (combined with C,c++,java)
3.python disadvantage
★ code execution is slow, compared to the C language, but now Python's asynchronous concurrency framework results in slow execution;
★python is an open source programming language, code cannot be encrypted, and of course there are tools to convert Python code to exe binary executable code, but the anti-decoding is also easy;

Application of 4.python

Software development: Game backstage, search, graphical interface, website, Scientific computing
System Management: Scripting, it automation tools

5. Install Python:

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6. View the Python version

Python-v View Version

Python uses Python interactively

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#!/usr/bin/python # # directly refers to the default python version of the system , so the python program is ported It may be problematic to run on other machines because the default Python version of someone else's system is inconsistent with what you expected.

#!/usr/bin/env Python # # referencing environment variables inside the custom python version , with strong portability

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# #代码里有中文时编码时设置编码格式#coding: Utf-8

* * #coding: Utf-8 # #设置编码格式

Four different encoding formats:

#coding: Utf-8
#coding =utf-8
#encoding: Utf-8
#encoding =utf-8

8.python common tools

Command: Ipython # #交互式使用python软件

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Command: Pycharm # #启动python软件

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9.the difference between Python and C scripts

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Python script

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C file

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Test:

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python comments

* * Single comment : # is often used as a single-line comment symbol, # any data on the right side of the line that begins is ignored as a comment.
* * Block Comment : Use a three-quote "" When you need bulk text or code . And, of course, three quotation marks can also be used to achieve multi-line text format printing.

Understanding character Encoding

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12. Encoding and decoding of characters

* * When storing data to the hard disk, need to take into account space-saving problems, so in the utf-8 format for storage;
* * When the data is read into memory, unified one encoding format for easy operation, in Unicode encoding format;
* * Therefore the character encoding and decoding must be skilled operation.

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python--Basic Knowledge