哪些文件编码支持Python 3源文件？ [英] Which file encodings are supported for Python 3 source files?

问题描述

在您告诉我阅读 PEP 0263 之前，请保留阅读...

Before you go telling me to read PEP 0263, keep reading...

我找不到任何详细信息的文档哪些文件编码支持Python 3源文件。

I can't find any documentation that details which file encodings are supported for Python 3 source files.

我发现了数百（数千）的问题，答案，帖子，电子邮件等关于如何声明 - 在源文件的顶部 - 编码的源文件，但他们都没有回答我的问题。与我一起想象（或者实际尝试）以下内容：

I've found hundreds (thousands?) of questions, answers, posts, emails, etc. about how to declare - at the top of your source file - the encoding of that source file, but none of them answer my question. Bear with me and imagine doing (or actually try) the following:

1. 打开记事本（我在Windows 7上使用常规的旧记事本，但我怀疑它很重要，我相信你的上级编辑可以做类似的事情。）


2. 输入你最喜爱的Python代码行（我使用 print（'Hello选择文件 - >保存


3. 选择一个文件夹和文件名（我使用E：\Temp\hello.py）


4. 将Encoding：设置从默认的ANSI更改为Unicode


5. 按保存


6. 打开命令提示符，切换到包含新文件的文件夹，然后尝试运行

1. Open Notepad (I'm using regular old Notepad on Windows 7, but I doubt it matters; I'm sure your superior editor can do something similar.)
2. Type your favorite line of Python code ( I used print( 'Hello, world!' ) )
3. Select "File" -> "Save"
4. Select a folder and file name ( I used "E:\Temp\hello.py" )
5. Change the "Encoding:" setting from the default "ANSI" to "Unicode"
6. Press "Save"
7. Open a command prompt, change to the folder containing your new file, and try to run it

这是我得到的输出：

E:\Temp>python --version
Python 3.4.1

E:\Temp>python "hello.py"
  File "hello.py", line 1
SyntaxError: Non-UTF-8 code starting with '\xff' in file hello.py on line 1, but no encoding declared; see http://python.org/dev/peps/pep-0263/ for details

现在，当我在记事本++ 中打开同一个文件时，看看编码菜单，它有选项选择UCS-2小尾编码。 维基百科告诉我，这基本上是UTF-16编码。随你。我真的不在乎更多的研究表明，我的编辑器在文件的前面插入了一个两字节BOM（字节顺序标记），值为'\xff\xfe'，表示文件编码。所以至少我知道Python所抱怨的'\xff'代码来自哪里。

Now, when I open this same file in Notepad++ and look at the "Encoding" menu, it has the option "Encode in UCS-2 Little Endian" selected. Wikipedia tells me that this is basically UTF-16 encoding. Whatever. I don't really care. More research reveals that my editor has inserted a two-byte BOM (Byte Order Mark) with a value of '\xff\xfe' at the front of the file to indicate the file encoding. So at least I know where the '\xff' code that Python is complaining about comes from.

所以我去阅读 PEP 0263 - 以及关于它的一切 - 在网络上，我尝试添加一个这样的评论到第一行文件

So I go and read PEP 0263 - and everything else regarding it - on the web, and I try adding a comment like this to the first line of the file

# coding: utf-16

与编码的各种不同的值，没有任何帮助。但是它不能帮助，对吧？因为Python甚至不能达到我的编码声明;它源于源文件的第一个字节窒息！

with all sorts of different values for the encoding, and nothing helps. But it can't help, right? Because Python isn't even getting as far as my encoding declaration; It's choking on the first byte of the source file!

所以我真正想知道的是...

So what I really want to know is...

1. 为什么Python 3解释器不能读取这个文件？


2. 如果是Unicode或UCS-2 Little Endian或 UTF-16或不支持，什么是???

1. Why can't the Python 3 interpreter read this file?
2. If "Unicode" or "UCS-2 Little Endian" or "UTF-16" or whatever isn't supported, what is???

我甚至发现 StackOverflow上的另一个问题，这似乎是我遇到的确切问题，但它被关闭 - 错误地我的意见 - 重复。 ：（

P.S. I even found another question on StackOverflow which seems to be the exact issue I'm having, but it was closed - erroneously in my opinion - as a duplicate. :(

---编辑---

有人问我的编译选项输出可能会有帮助？

Someone asked for my "compiled options". Here's some output. Maybe it will help?

E:\Temp>python
Python 3.4.1 (v3.4.1:c0e311e010fc, May 18 2014, 10:38:22) [MSC v.1600 32 bit (Intel)] on win32
Type "help", "copyright", "credits" or "license" for more information.
>>> import sysconfig
>>> print( sysconfig.get_config_vars() )
{'EXT_SUFFIX': '.pyd', 'srcdir': 'C:\\Python34', 'py_version_short': '3.4', 'base': 'C:\\Python34', 'prefix': 'C:\\Python34', 'projectbase': 'C:\\Python34', 'INCLUDEPY': 'C:\\Python34\\Include', 'platbase': 'C:\\Python34', 'py_version_nodot': '34', 'exec_prefix': 'C:\\Python34', 'EXE': '.exe', 'installed_base': 'C:\\Python34', 'SO': '.pyd', 'installed_platbase': 'C:\\Python34', 'VERSION': '34', 'BINLIBDEST': 'C:\\Python34\\Lib', 'LIBDEST': 'C:\\Python34\\Lib', 'userbase': 'C:\\Users\\alonghi\\AppData\\Roaming\\Python', 'py_version': '3.4.1', 'abiflags': '', 'BINDIR': 'C:\\Python34'}
>>>

推荐答案

源编码必须是：

1. 所讨论的Python版本支持的编码。 （这取决于版本和平台，例如，您只能在Windows上获得 mbcs 。）

松散ASCII兼容，足够使用＃编码：声明可以使用 ascii 读取，这是任何声明被读取。请参阅PEP0263概念项目1。

Loosely ASCII-compatible, enough that the # coding: declaration can be read using ascii which is the initial source encoding before any declaration is read. See PEP0263 ‘Concepts’ item 1.

Windows误导称为Unicode的编码，UTF-16LE不是ASCII兼容的（通常是一桶你应该尽量避免使用的问题）。 Python将需要特殊的特定编码支持来检测UTF-16源文件，此功能现在已拒绝

The encoding that Windows misleadingly calls "Unicode", UTF-16LE, is not ASCII-compatible (and generally is a barrel of problems you should try to avoid using). Python would need special encoding-specific support to detect UTF-16 source files and this feature has been declined for now.

您应该使用的＃编码：几乎总是UTF-8。

The # coding: you should use is almost invariably UTF-8.

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