擅长:python、mysql、java
<p>根据注释,可以将<code>a</code>和{<cd2>}放入一个无序的<a href="https://docs.python.org/3/library/stdtypes.html#set-types-set-frozenset" rel="nofollow noreferrer">^{<cd3>}</a>:</p>
<pre><code>dict_choice = {frozenset((a, b)): value}
</code></pre>
<hr/>
<p>如果需要自动执行此操作,可以创建自己的<a href="https://docs.python.org/3/library/collections.abc.html#collections.abc.MutableMapping" rel="nofollow noreferrer">^{<cd4>}</a>:</p>
^{pr2}$
<p>使用中:</p>
<pre><code>>>> d = MyDict([((1, 2), 'hello'), ((3, 4), 'world')])
>>> d[(2, 1)]
'hello'
</code></pre>
<p>但是请注意,对于其他类型的键,这可能会有意外的行为:</p>
<pre><code>>>> d['hello'] = 'world'
>>> d['hole']
'world'
>>> d[1] = 2
Traceback (most recent call last):
File "python", line 1, in <module>
File "python", line 14, in __setitem__
TypeError: 'int' object is not iterable
</code></pre>