擅长:python、mysql、java
<p>您可以使用<code>extract</code>函数:</p>
<pre><code>df['column B'] = df['column A'].str.extract('(Changing[^-]*)')
df
column A column B
0 TTT-Changing Car-BBBB-KKKK Changing Car
1 TTT-KKKK - Changing device-KKKK Changing device
2 Releasing device-RRRR-KKKK-TTTT NaN
3 RRRR-BBBB-Switching Car-TTTT NaN
4 Login issue -RRRR-KKKK-TTTT NaN
5 CCCC-Activation issue-RRRR-KKKK-TTTT NaN
</code></pre>
<h2>编辑</h2>
<P>如果要替换内容,请考虑使用字典:</P>
<pre><code>dct = {'changing': 'Change',
'change':'Change',
'activation':'Activation',
'registration':'Activation'}
pat = f"(?i).*\\b({'|'.join(dct.keys())})\\b.*"
df['column A'].str.replace(pat, lambda x: dct.get(x.group(1).lower(), None))
0 Change
1 Change
2 Releasing device-RRRR-KKKK-TTTT
3 RRRR-BBBB-Switching Car-TTTT
4 Login issue -RRRR-KKKK-TTTT
5 Activation
Name: column A, dtype: object
</code></pre>