这是从哪里来的：-*-编码：utf-8-*-

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.

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.

# -*- 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?

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.

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

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.