擅长:python、mysql、java
<p>IIUC,您可以使用<code>itertools.accumulate</code>生成前向填充:</p>
<pre><code>>>> from itertools import accumulate
>>> a = [None,1,2,3,None,4,None,None]
>>> list(accumulate(a, lambda x,y: y if y is not None else x))
[None, 1, 2, 3, 3, 4, 4, 4]
</code></pre>