擅长:python、mysql、java
<p><a href="https://stackoverflow.com/a/61265773/5637137">jezrael's answer</a>可能是最好的,可读性更好,但是如果您想在一行程序中使用<a href="https://pandas.pydata.org/pandas-docs/stable/reference/api/pandas.DataFrame.dropna.html" rel="nofollow noreferrer">^{<cd1>}</a>。尽管名称很吓人,但它不会改变原始数据帧,除非您使用参数<code>inplace=True</code>调用它</p>
<pre class="lang-py prettyprint-override"><code>>>> df['colC'] = df.dropna().apply(lambda x: x[0][int(x[1]):], axis=1)
>>> print(df)
colA colB colC
0 abcde 4.0 e
1 abcde 2.0 cde
2 abcde 1.0 bcde
3 NaN NaN NaN
4 wxyz 3.0 z
5 wxyz 2.0 yz
</code></pre>