Python character encoding file

2. Character encoding Development
   

   ASCII 255 only supports English letters and numbers, special characters 1bytes

   Unicode Chinese and English unified 2bytes

   Utf-8 Chinese >3bytes English >1bytes

4. Bytes Type

   Text data is always Unicode represented by the STR type, while binary data is represented by the bytes type

   Binary data is used in video, audio files, and sending socket networks to transmit data etc.

6. string into binary Str.encode ("Encoding=utf-8")

   Binary into string B ' \xe2\x82 '. Decode ("Encoding=utf-8")

8. The file handle is the memory address of the file object

10. Character encoding and transcoding

    The ASCII code table cannot be saved in Chinese, and the default system character encoding for Windows is GBK.

    Unicode character encoding can store all the characters in the world, but all characters occupy two bytes, the original 2M

    English files require 4M of storage space after using Unicode

12. Utf-8 string converted to GBK character

    Any two encoded strings must be converted by first converting to Unicode encoding to implement the

14. unicode (Uniform Code, universal Code, single code) is a character encoding used on a computer . Span style= "Font-family:verdana, Arial, Helvetica, Sans-serif;font-size:14px;line-height:21px;background-color:rgb (255,255,255); " > Unicode is created to address the limitations of traditional character encoding schemes, which set a uniform and unique binary encoding for each character in each language.

16. garbled appearance basically two kinds of situation:

    1, character encoding does not have

    2, character encoding conflict, when people write this program, the specified character set and the character set we use are not in the right place

18. pyton when explaining the. py file , the default is to give him a code is ascii code

20. Unicode encoding is the default in Python3

22. Because in Python2. The default is ASCII encoding in x, you specify the encoding in the file as UTF-8, but UTF-8 if you want to turn GBK words can not directly turn, need Unicode to do a forwarding site.

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26. str = "Hello"//This string is encoded with Utf-8

    New_str=str.decode (' utf-8 ')//pass STR original encoding format to decode function transcode to Unicode encoding

    ret = New_str.encode (' GBK ')//convert Unicode encoding to GBK encoded string

    
    

28. str= u "Hello" add a U letter in front of the string to indicate that this string is set to Unicode encoding

Coding

The python interpreter encodes the content when it loads the code in the. py file (default Ascill) So if you don't specify the encoding type,

If you have Chinese, you will get an error.

Python's working process

Python read the code into memory 2, lexical parsing 3, put into the compiler---"Generate byte code 4, execute bytecode---" Generate Machine code CPU execution

Variable

The value of the string can not be modified, he is in memory is continuous, if you want to change the words must be reserved in the back so do not support the modification!
String attributes, once modified, re-created

This article from "Number One" blog, declined reprint!

Python character encoding file