擅长:python、mysql、java
<p>使用<code>collection.defaultdict</code></p>
<p><strong>例如:</strong></p>
<pre><code>from collections import defaultdict
dictionary = defaultdict(list)
with open('%Filename%') as f:
for line in f:
num, key = line.strip().split()
dictionary[key].append(num)
print(dictionary)
</code></pre>
<hr/>
<p>或<code>dict.setdefault</code></p>
<p><strong>例如:</strong></p>
<pre><code>dictionary = {}
with open('%Filename%') as f:
for line in f:
num, key = line.strip().split()
dictionary.setdefault(key, []).append(num)
print(dictionary)
</code></pre>
<ul>
<li><strong>注意:</strong>您需要使用<code>list.append</code>将元素附加到列表中。你知道吗</li>
</ul>