擅长:python、mysql、java
<p>也许你在寻找:</p>
<pre><code>>>> from collections import defaultdict
>>> pair = defaultdict(dict)
>>> pair[3][2]='hello'
>>>
>>> pair
defaultdict(<type 'dict'>, {3: {2: 'hello'}})
>>>
>>> pair[3]
{2: 'hello'}
>>>
</code></pre>