Python Coding issues

The following applies to Python version 2.7.

1. About ASCII Unicode Utf-8:

ascii:127 number A--Z--1221 bytes represents one character (255)

Unicode: typically two bytes (65535) represent a character, and an uncommon character may represent a character in four bytes. The ASCII binary representation in Unicode is preceded by 0. (The encoding used by the computer is Unicode)

If a document is full of English characters, the use of Unicode can result in a waste of memory, resulting in utf-8 (variable length encoding).

ASCII consumes one byte of memory in Utf-8, while Chinese occupies three bytes.

2. Unicode encoding is used in the computer, and when it comes to hard disk storage, Unicode is converted to utf-8 storage. For example: Notepad for storage.

Similarly, on a Web page, the Unicode data is converted to utf-8 displayed on the browser.

ASCII-to-digital conversion in 3.Python

>>> Ord ('A')+ >>> chr  A'

4.Python added support for Unicode, which is represented by a string in Unicode u‘...‘

Print u'  Chinese '  >>> u '  u ' ' \u4e2d '

5. u‘xxx‘ Convert to UTF-8 encoding ‘xxx‘ encode(‘utf-8‘) method: (Unicode to Utf-8)

 >>> u " abc  " . Encode ( " utf-8  Span style= "COLOR: #800000" > " )  "  Span style= "COLOR: #800000" >abc   " >>> u  "  Chinese   ". Encode ("   Utf-8   " )   '  

6. In turn, convert the string represented by the UTF-8 encoding ‘xxx‘ to a Unicode string u‘xxx‘ using the decode(‘utf-8‘) method: (Utf-8 converted to Unicode )

>>>'ABC'. Decode ('Utf-8') U'ABC'>>>'\xe4\xb8\xad\xe6\x96\x87'. Decode ('Utf-8') U'\u4e2d\u6587'>>>Print '\xe4\xb8\xad\xe6\x96\x87'. Decode ('Utf-8') Chinese

7.Python file header Specifies the encoding format to read (in case the file contains Chinese, and the Chinese string must be a Unicode string)

# !/usr/bin/env python # -*-coding:utf-8-*-

Python Coding issues