擅长:python、mysql、java
<p>为了完全概括这一点,使它在所有情况下都能工作,我将采取一些额外的步骤和<code>regex</code>来实现您的预期输出:</p>
<pre><code>df['Start_letter'] = df['Col'].str.extract('(^[A-Za-z])').fillna('') # Extract the first letter
df['End_letter'] = df['Col'].str.extract('([A-Za-z]$)').fillna('') # Extract the last letter
df['Nums'] = df['Col'].str.replace('[A-Za-z]', '').apply(lambda x: x.zfill(4)) # Extract the numbers between the letters
df['Col'] = df['Start_letter'] + df['Nums'] + df['End_letter']
df = df.iloc[:, :1]
</code></pre>
<hr/>
<pre><code> Col
0 A0002
1 A0011
2 A0001
3 A0001A
4 A0002
5 A0003A
6 A0002
</code></pre>