擅长:python、mysql、java
<p>是的,如果键不在字典中,<a href="https://docs.python.org/2/library/stdtypes.html?highlight=dict.get#dict.get" rel="nofollow">dict.get</a>函数返回<code>default</code>。但是<code>default</code>被计算。在</p>
<p>你可以用这样的中级词典。在</p>
<pre><code>main = dict(a=5, c=3)
backup = dict(a=6, b=9, c=4)
intermediate = dict(backup, **main)
print(intermediate['a'])
print(intermediate['b'])
</code></pre>
<p>你会得到:</p>
^{pr2}$
<p>以及:</p>
<pre><code>print(intermediate['d'])
</code></pre>
<p>你有个例外:</p>
^{4}$