擅长:python、mysql、java
<p>您的代码:</p>
<pre><code>if 'fruit' not in foods:
foods['fruit'] = {}
if 'apples' not in foods['fruit']:
foods['fruit']['apples'] = []
foods['fruit']['apples'].append('Granny Smith')
</code></pre>
<p>将写为:</p>
<pre><code>foods.setdefault('fruit', {}).setdefault('apples', []).append('Granny Smith')
</code></pre>
<p>使用<a href="https://docs.python.org/2/library/stdtypes.html#dict.setdefault" rel="nofollow">^{<cd1>}</a></p>