Python 3.6 要让所有字典有序？

https://www.reddit.com/r/Python/comments/55iqpo/guido_on_dicts_in_python_36/

https://mail.python.org/pipermail/python-dev/2016-September/146348.html

I've been asked about this. Here's my opinion on the letter of the law in 3.6:

• keyword args are ordered
• the namespace passed to a metaclass is ordered by definition order
• ditto for the class dict

A compliant implementation may ensure the above three requirements either by making all dicts ordered, or by providing a custom dict subclass (e.g. OrderedDict) in those three cases.

I'd like to handwave on the ordering of all other dicts. Yes, in CPython 3.6 and in PyPy they are all ordered, but it's an implementation detail. I don't want to force all other implementations to follow suit. I also don't want too many people start depending on this, since their code will break in 3.5. (Code that needs to depend on the ordering of keyword args or class attributes should be relatively uncommon; but people will start to depend on the ordering of all dicts all too easily. I want to remind them that they are taking a risk, and their code won't be backwards compatible.)

--Guido