擅长:python、mysql、java
<pre><code>import collections
def bind(dict1):
dict2 = collections.defaultdict(set)
for k, v in dict1.items():
dict2[v].add(k)
return dict2
result = bind({'Europa': 'Jupiter', 'Psamathe': 'Neptune', 'Cordelia': 'Uranus', 'Cupid': 'Uranus'})
print(result)
</code></pre>
<p>收益率</p>
<blockquote>
<p>defaultdict(, {'Jupiter': set(['Europa']), 'Neptune':
set(['Psamathe']), 'Uranus': set(['Cordelia', 'Cupid'])})</p>
</blockquote>
<hr/>
<p>或者,可以让<code>dict2</code>成为<code>dict</code>,而不是<code>collections.defaultdict(set)</code>,并使用<code>setdefault</code>方法:</p>
^{pr2}$
<hr/>
<p>参考文献:</p>
<ul>
<li><a href="http://docs.python.org/2/library/stdtypes.html#set.add" rel="nofollow">set.add</a></li>
<li><a href="http://docs.python.org/2/library/collections.html#collections.defaultdict" rel="nofollow">collection.defaultdict</a></li>
<li><a href="http://docs.python.org/2/library/stdtypes.html#dict.setdefault" rel="nofollow">dict.setdefault</a></li>
</ul>