这是从哪里来的：-*-编码：utf-8-*- Python 实用宝典

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问题：这是从哪里来的：--编码：utf-8--

Python将以下内容识别为定义文件编码的指令：

# -*- coding: utf-8 -*-

我确实在（-*- var: value -*-）之前看到过这种说明。它从何而来？完整规范是什么，例如，值可以包含空格，特殊符号，换行符，甚至-*-本身吗？

我的程序将编写纯文本文件，我想使用这种格式在其中包含一些元数据。

Python recognizes the following as instruction which defines file’s encoding:

# -*- coding: utf-8 -*-

I definitely saw this kind of instructions before (-*- var: value -*-). Where does it come from? What is the full specification, e.g. can the value include spaces, special symbols, newlines, even -*- itself?

My program will be writing plain text files and I’d like to include some metadata in them using this format.

回答 0

这种指定Python文件编码的方式来自PEP 0263-定义Python源代码编码。

GNU Emacs也可以识别它（请参阅Python语言参考，2.1.4编码声明），尽管我不知道它是否是第一个使用该语法的程序。

This way of specifying the encoding of a Python file comes from PEP 0263 – Defining Python Source Code Encodings.

It is also recognized by GNU Emacs (see Python Language Reference, 2.1.4 Encoding declarations), though I don’t know if it was the first program to use that syntax.

回答 1

# -*- coding: utf-8 -*-是Python 2的东西。在Python 3+中，源文件的默认编码已经是UTF-8，并且该行是无用的。

请参阅：我应该在Python 3中使用编码声明吗？

pyupgrade是一个可以在代码上运行的工具，用于从Python 2中删除这些注释和其他不再有用的遗留物，例如让所有类都继承自object。

# -*- coding: utf-8 -*- is a Python 2 thing. In Python 3+, the default encoding of source files is already UTF-8 and that line is useless.

See: Should I use encoding declaration in Python 3?

pyupgrade is a tool you can run on your code to remove those comments and other no-longer-useful leftovers from Python 2, like having all your classes inherit from object.

回答 2

这就是所谓的文件局部变量，Emacs可以理解并相应地进行设置。请参阅Emacs手册中的相应部分 -您可以在文件的页眉或页脚中定义它们

This is so called file local variables, that are understood by Emacs and set correspondingly. See corresponding section in Emacs manual – you can define them either in header or in footer of file

回答 3

在PyCharm中，我将其省略。它将关闭底部的UTF-8指示器，并警告该编码为硬编码。不要以为您需要上面提到的PyCharm评论。

In PyCharm, I’d leave it out. It turns off the UTF-8 indicator at the bottom with a warning that the encoding is hard-coded. Don’t think you need the PyCharm comment mentioned above.