擅长:python、mysql、java
<p>对其值的<code>keys</code>进行排序将得到所需的结果。你知道吗</p>
<pre><code>>>> bird = { 'a': ['Parrot'], 'b': ['Columbidae'], 'c': ['Hummingbird'], 'd': ['kiwi', 'Crow', 'Sparrow']}
>>> print sorted(bird.keys(), key = lambda x:len(bird[x]))[-1]
>>> d
</code></pre>
<p>您可以在函数中嵌入这一行:</p>
<pre><code>bird = { 'a': ['Parrot'], 'b': ['Columbidae'], 'c': ['Hummingbird']}
bird['d'] = ['Finch']
bird['d'].append('Owl')
bird['d'].append('Penguin')
def func(a):
return sorted(bird.keys(), key = lambda x:len(bird[x]))[-1]
print func(bird)
</code></pre>
<p>或者正如Padraic所建议的,将<code>max</code>函数与lambda一起使用可以以最小的开销完成您的工作:</p>
<pre><code>def func(a):
return max(bird.keys(), key = lambda x:len(bird[x]))
</code></pre>