擅长:python、mysql、java
<p>我试过了,你想使用<code>val not in inverse</code>,但如果“列表在dict中”,则无法检查它。(<code>val</code>是一个列表)</p>
<p>对于您的代码,一个简单的更改将执行您想要的操作:</p>
<pre><code>def invert_dict(d):
inverse = dict()
for key in d:
# Go through the list that is saved in the dict:
for item in d[key]:
# Check if in the inverted dict the key exists
if item not in inverse:
# If not create a new list
inverse[item] = [key]
else:
inverse[item].append(key)
return inverse
</code></pre>