如何在Python 中使用UTF-8 编码 && Python 使用 注释,Python ,UTF-8 编码 , Python  注释

PIP

$ pip install beautifulsoup4

$ python -m pip install --upgrade pip

PyCharm 设置 Python Script 模板内容：
创建.py文件时自动添加 #coding utf8 文件头
File > Settings > Editor > File and Code Templates > Python Script>
#coding utf8

参考图片：http://img.imooc.com/57d6c0eb0001d66d05000305.jpg
参考链接：http://www.imooc.com/qadetail/127992

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python spider demo:

# coding:utf8
__author__ = 'xray'
import urllib2
import cookielib

url = "https://rollbar.com/docs/"

print '第一种方法'
response1 = urllib2.urlopen(url)
print response1.getcode()
print len(response1.read())

print '第二种方法'
request = urllib2.Request(url)
request.add_header("user-agent", "Mozilla/5.0")
response2 = urllib2.urlopen(request)
print response2.getcode()
print response2.read()

print '第三种方法'
cj = cookielib.CookiJar()
opener = urllib2.build_opener(urllib2.HTTPCookieProcessor(cj))
urllib2.install_opener(opener)
response3 = urllib2.urlopen(url)
print response3.getcode()
print cj
print response3.read()

zh-CN error:

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如何在Python 中使用UTF-8 编码 && Python 使用 注释

PEP 263 -- Defining Python Source Code Encodings

PEP:

263

Title:

Defining Python Source Code Encodings

Author:

Marc-André Lemburg , Martin von Löwis

Status:

Final

Type:

Standards Track

Created:

06-Jun-2001

Python-Version:

2.3

Post-History:

 

Abstract

This PEP proposes to introduce a syntax to declare the encoding of  
a Python source file. The encoding information is then used by the  
Python parser to interpret the file using the given encoding. Most  
notably this enhances the interpretation of Unicode literals in  
the source code and makes it possible to write Unicode literals  
using e.g. UTF-8 directly in an Unicode aware editor.

Problem

In Python 2.1, Unicode literals can only be written using the  
Latin-1 based encoding "unicode-escape". This makes the  
programming environment rather unfriendly to Python users who live  
and work in non-Latin-1 locales such as many of the Asian  
countries. Programmers can write their 8-bit strings using the  
favorite encoding, but are bound to the "unicode-escape" encoding  
for Unicode literals.

Proposed Solution

I propose to make the Python source code encoding both visible and  
changeable on a per-source file basis by using a special comment  
at the top of the file to declare the encoding.

To make Python aware of this encoding declaration a number of  
concept changes are necessary with respect to the handling of  
Python source code data.

Defining the Encoding

Python will default to ASCII as standard encoding if no other  
encoding hints are given.

**To define a source code encoding, a magic comment must  
be placed into the source files either as first or second  
line in the file**, such as:

      # coding=<encoding name>

or (using formats recognized by popular editors)

      #!/usr/bin/python  
      # -\*- coding: <encoding name> -\*-

or

      #!/usr/bin/python  
      # vim: set fileencoding=<encoding name> :

More precisely, the first or second line must match the regular  
expression "^\[ \\t\\v\]\*#.\*?coding\[:=\]\[ \\t\]\*(\[-\_.a-zA-Z0-9\]+)".  
The first group of this  
expression is then interpreted as encoding name. If the encoding  
is unknown to Python, an error is raised during compilation. There  
must not be any Python statement on the line that contains the  
encoding declaration.  If the first line matches the second line  
is ignored.

To aid with platforms such as Windows, which add Unicode BOM marks  
to the beginning of Unicode files, the UTF-8 signature  
'\\xef\\xbb\\xbf' will be interpreted as 'utf-8' encoding as well  
(even if no magic encoding comment is given).

If a source file uses both the UTF-8 BOM mark signature and a  
magic encoding comment, the only allowed encoding for the comment  
is 'utf-8'.  Any other encoding will cause an error.

Examples

These are some examples to clarify the different styles for  
defining the source code encoding at the top of a Python source  
file:

1. With interpreter binary and using Emacs style file encoding  
   comment:

      #!/usr/bin/python  
      # -\*- coding: latin-1 -\*-  
      import os, sys  
      ...

      #!/usr/bin/python  
      # -\*- coding: iso-8859-15 -\*-  
      import os, sys  
      ...

      #!/usr/bin/python  
      # -\*- coding: ascii -\*-  
      import os, sys  
      ...

2. Without interpreter line, using plain text:

      # This Python file uses the following encoding: utf-8  
      import os, sys  
      ...

3. Text editors might have different ways of defining the file's  
   encoding, e.g.

      #!/usr/local/bin/python  
      # coding: latin-1  
      import os, sys  
      ...

4. Without encoding comment, Python's parser will assume ASCII  
   text:

      #!/usr/local/bin/python  
      import os, sys  
      ...

5. Encoding comments which don't work:

   Missing "coding:" prefix:

      #!/usr/local/bin/python  
      # latin-1  
      import os, sys  
      ...

   Encoding comment not on line 1 or 2:

      #!/usr/local/bin/python  
      #  
      # -\*- coding: latin-1 -\*-  
      import os, sys  
      ...

   Unsupported encoding:

      #!/usr/local/bin/python  
      # -\*- coding: utf-42 -\*-  
      import os, sys  
      ...

Concepts

The PEP is based on the following concepts which would have to be  
implemented to enable usage of such a magic comment:

1. The complete Python source file should use a single encoding.  
   Embedding of differently encoded data is not allowed and will  
   result in a decoding error during compilation of the Python  
   source code.

   Any encoding which allows processing the first two lines in the  
   way indicated above is allowed as source code encoding, this  
   includes ASCII compatible encodings as well as certain  
   multi-byte encodings such as Shift\_JIS. It does not include  
   encodings which use two or more bytes for all characters like  
   e.g. UTF-16. The reason for this is to keep the encoding  
   detection algorithm in the tokenizer simple.

2. Handling of escape sequences should continue to work as it does  
   now, but with all possible source code encodings, that is  
   standard string literals (both 8-bit and Unicode) are subject to  
   escape sequence expansion while raw string literals only expand  
   a very small subset of escape sequences.

3. Python's tokenizer/compiler combo will need to be updated to  
   work as follows:

   1. read the file

   2. decode it into Unicode assuming a fixed per-file encoding

   3. convert it into a UTF-8 byte string

   4. tokenize the UTF-8 content

   5. compile it, creating Unicode objects from the given Unicode data  
      and creating string objects from the Unicode literal data  
      by first reencoding the UTF-8 data into 8-bit string data  
      using the given file encoding

   Note that Python identifiers are restricted to the ASCII  
   subset of the encoding, and thus need no further conversion  
   after step 4.

Implementation

For backwards-compatibility with existing code which currently  
uses non-ASCII in string literals without declaring an encoding,  
the implementation will be introduced in two phases:

1. Allow non-ASCII in string literals and comments, by internally  
   treating a missing encoding declaration as a declaration of  
   "iso-8859-1". This will cause arbitrary byte strings to  
   correctly round-trip between step 2 and step 5 of the  
   processing, and provide compatibility with Python 2.2 for  
   Unicode literals that contain non-ASCII bytes.

   A warning will be issued if non-ASCII bytes are found in the  
   input, once per improperly encoded input file.

2. Remove the warning, and change the default encoding to "ascii".

The builtin compile() API will be enhanced to accept Unicode as  
input. 8-bit string input is subject to the standard procedure for  
encoding detection as described above.

If a Unicode string with a coding declaration is passed to compile(),  
a SyntaxError will be raised.

SUZUKI Hisao is working on a patch; see \[2\] for details. A patch  
implementing only phase 1 is available at \[1\].

Phases

Implementation of steps 1 and 2 above were completed in 2.3,  
except for changing the default encoding to "ascii".

The default encoding was set to "ascii" in version 2.5.

Scope

This PEP intends to provide an upgrade path from the current  
(more-or-less) undefined source code encoding situation to a more  
robust and portable definition.

References

\[1\] Phase 1 implementation:  
    [http://python.org/sf/526840](https://python.org/sf/526840)  
\[2\] Phase 2 implementation:  
    [http://python.org/sf/534304](https://python.org/sf/534304)

History

1.10 and above: see CVS history  
1.8: Added '.' to the coding RE.  
1.7: Added warnings to phase 1 implementation. Replaced the  
     Latin-1 default encoding with the interpreter's default  
     encoding. Added tweaks to compile().  
1.4 - 1.6: Minor tweaks  
1.3: Worked in comments by Martin v. Loewis:  
     UTF-8 BOM mark detection, Emacs style magic comment,  
     two phase approach to the implementation

Copyright

This document has been placed in the public domain.

Source: https://hg.python.org/peps/file/tip/pep-0263.txt

demo:

#!/usr/bin/python

-*- coding: utf-8 -*-

from django.shortcuts import render

from django.http import HttpResponse

Create your views here.

def index(request):
return HttpResponse('

Hello, this is the first page of my Django(迪亚戈) Web App!

')

return HttpResponse('

Hello, this is the first page of my Django(迪亚戈) Web App!

')

参考链接：

http://www.crifan.com/python_head_meaning_for_usr_bin_python_coding_utf-8/

https://www.python.org/dev/peps/pep-0263/

https://raw.githubusercontent.com/xgqfrms/Python/master/DjangoApp/main_app/views.py

https://github.com/xgqfrms/Python/blob/gh-pages/DjangoApp/main_app/views.py

# How to get a DOM element's `::before` content with JavaScript?

https://stackoverflow.com/questions/44342065/how-to-get-a-dom-elements-before-content-with-javascript

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