擅长:python、mysql、java
<p>你可能有</p>
<pre><code>m_dict = {'A': ['aa', 'bb', 'cc'], 'B': ['bb'], 'C': ['aa']}
</code></pre>
<p>我要这样做:</p>
^{pr2}$
<h2>编辑</h2>
<p>考虑到您的格式,它可能更符合以下行:</p>
<pre><code>m_array = [['A', 'aa'], ['A', 'bb'], ['A', 'cc'], ['B', 'bb'], ['C', 'aa']]
res = defaultdict(lambda: defaultdict(int))
for k, v in m_array:
res[k][v] = 1
</code></pre>
<p>这两者都给出了:</p>
<pre><code>>>> res['A']['aa']
1
>>> res['B']['aa']
0
</code></pre>