Python SyntaxError:fi中的非ASCII字符'\xe2'

Question

我刚刚从在Python3下运行Django应用程序切换到使用Python2.7。我现在得到这个错误：

SyntaxError: Non-ASCII character '\xe2' in file /Users/user/Documents/workspace/testpro/testpro/apps/common/models/vendor.py on line 9, but no encoding declared; see http://www.python.org/peps/pep-0263.html for details

它所指的代码只是一个注释：

class Vendor(BaseModel):
    """
    A company manages owns one of more stores.‎
    """
    name = models.CharField(max_length=255)


    def __unicode__(self):
        return self.name

为什么？

这有效：

 class Vendor(BaseModel):
        """

        """
        name = models.CharField(max_length=255)


        def __unicode__(self):
            return self.name

Answer 1

您的docstring中有一个UTF-8编码的U+200E LEFT-TO-RIGHT MARK：

'\n    A company manages owns one of more stores.\xe2\x80\x8e\n    '

从代码中删除该代码点（并尝试使用代码编辑器，而不是文字处理器），或者将PEP-263编码注释放在文件顶部：

# encoding=utf8

Python 3默认使用UTF-8，Python 2默认使用ASCII作为源代码，除非您添加了该注释。

Answer 2

正如已经由Martijn Pieters通过pointed out一样，docstring包含一个UTF-8（即非ASCII）字符。

我想详细说明一下声明文件编码的正确方法。如PEP 263所述：

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 following regular expression:

^[ \t\f]*#.*?coding[:=][ \t]*([-_.a-zA-Z0-9]+)

这意味着什么（用answer to another question来概括）：

So, you can put pretty much anything before the "coding" part, but stick to "coding" (with no prefix) if you want to be 100% python-docs-recommendation-compatible.

因此，就本案而言，建议的“神奇评论”是：

# coding=utf8

或：

#!/usr/bin/python
# -*- coding: utf8 -*-

或：

#!/usr/bin/python
# vim: set fileencoding=utf8 :