擅长:python、mysql、java
<p>下面是一个实际使用<code>defaultdict</code>在普通<code>dict</code>上提供的功能的示例:</p>
<pre><code>from collections import defaultdict
x=['a','3','4','b','1','2','c','4','5']
key='<unknown>' # needed if the first value of x is a number
category = defaultdict(list) # defaultdict with list
for i in x:
if i.isalpha():
key = i;
else:
category[key].append(i) # no need to initialize with an empty list
print category
</code></pre>
<p>另外:对于类实例,应该使用小写的名称。大写名称通常是为类保留的。阅读<a href="https://www.python.org/dev/peps/pep-0008" rel="nofollow">pep8</a>以获取样式指南。在</p>