擅长:python、mysql、java
<p>你可以使用<a href="https://docs.python.org/3/library/collections.html#collections.Counter" rel="nofollow noreferrer">^{<cd1>}</a></p>
<pre><code>>>> from collections import Counter
>>> c = Counter()
>>> for l in a:
... c.update(set(l))
...
>>> c
Counter({'apple': 4, 'cat': 3, 'dog': 2, 'deer': 1, 'cow': 1})
>>> [key for key, value in c.items() if value >= 0.7 * len(a)]
['cat', 'apple']
</code></pre>