Python Coding and code comments

First, Content coding

It is clear that the ASCII code cannot represent all the words and symbols in the world, so it is necessary to create a new encoding that can represent all the characters and symbols, namely: Unicode

Unicode (Uniform Code, universal Code, single code) is a character encoding used on a computer. Unicode is created to address the limitations of the traditional character encoding scheme, which sets a uniform and unique binary encoding for each character in each language, which specifies that characters and symbols are represented by at least 16 bits (2 bytes), that is: 2 **16 = 65536,
Note: Here is a minimum of 2 bytes, possibly more

UTF-8, which is compression and optimization of Unicode encoding, does not use a minimum of 2 bytes, but instead classifies all characters and symbols: the contents of the ASCII code are saved with 1 bytes, the characters in Europe are saved in 2 bytes, and the characters in East Asia are saved in 3 bytes ...

Therefore, when the Python interpreter loads the code in the. py file, it encodes the content (the default ascill), if it is the following code:

Error: ASCII code cannot be expressed in Chinese

[email protected] ~]# cat hellow.py #!/usr/bin/env pythonprint "Hello World" print "Hello, worlds" [[email protected] ~]# python he llow.py file "hellow.py", line 4syntaxerror:non-ascii character ' \xe4 ' in File hellow.py on line 4, but no encoding dec lared; See http://www.python.org/peps/pep-0263.html for details

Correction: It should be shown to tell the Python interpreter what code to use to execute the source code, i.e.:

[[email protected] ~]# cat hellow.py #!/usr/bin/env python#-*-coding:utf-8-*-print "Hello World" print "Hello, worlds" [[Email P rotected] ~]# python hellow.py Hello worlds Hello World

Second, the note

When the line stares: # is annotated content

Multiline Comment: "" "Annotated Content" ""

three . Write and execute Python code flow

1, create xxx.py file PS: Do not have Chinese path, the file name is not Chinese

2. Write code

A. Add #!/usr/bin/env python and #-*-coding:utf-8-*-two lines at the beginning of the. py file

B. Write function code
#写功能代码的规则

3. Execute code

A. Open the terminal

Function key +r re-enter CMD press ENTER (Windows)

B. Path to Python code files

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Python Coding and code comments