Python Learning note 8-9 (character encoding and binary)

Character encoding

When the Python interpreter loads the code in the. py file, the content is encoded (default ASCII)

Binary

Example: Ancient beacon, ignition and not ignition only two states, the transmission of information too little.

Agreed ignition number 1, representing 1-100

Ignition number 2, representing 101-1000

Ignition Number 3, representing 1001-5000

Ignition number 4, representing 5001-1000

Although there is progress, but not accurate enough

If you introduce binary, you can accurately represent any number

Character encoding

Conversion of binary and letter

ASCII (American Standards Code for information Interchange, US standard Information Interchange code)

GB2312 (1980) More than 7,445 kanji characters, including 6,763 Chinese characters and 682 other symbols.

GBK1.0 (1995) contains 21,886 symbols, which are divided into Chinese characters and graphic symbols: 21,003 characters in the Chinese character area.

GB18030 (2000) replaces GBK1.0 's official national standard. The standard contains 27,484 Chinese characters, but also includes Tibetan, Mongolian, Uyghur and other major minority characters. Now the PC platform must support GB18030, the embedded products are not required. So mobile phones, MP3 generally only support GB2312.

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. All characters account for 2 bytes.

UTF-8, 1 bytes in English characters, 3 bytes in Chinese

Summarized as follows:

ASCII 255 1bytes

-->1980 gb2312 7,445 Kanji characters

-->1995 GBK1.0 21,885 X

-->2000 GB18030 27,484 X

--Unicode 2bytes

--Utf-8 En:1byte, zh:3bytes

Python3 Maximum difference than Python2, default support character encoding set

Python2 Chinese support, the first line input: #-*-Coding:utf-8-*-

Python3 Default Support Utf-8

Example:

Name = (name)

Operation will be error, ASCII code can not be expressed in Chinese, need to be modified to:

#-*-Coding:utf-8-*-name = (name)

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Python Learning note 8-9 (character encoding and binary)