擅长:python、mysql、java
<p>以下是如何使用<code>re</code>:</p>
<pre><code>import pandas as pd
from re import sub, findall
df = pd.DataFrame(...)
df['Col_A'] = [sub('\d\d\d\d','2019',m)
if findall('\d\d\d\d',m)
else sub('\d\d','19',m)
for m in df['Col_A']]
</code></pre>
<hr/>
<p>更新:另一种方式:</p>
<pre><code>import pandas as pd
from re import sub, findall
df = pd.DataFrame(...)
df['Col_A'] = df.Col_A.map(lambda m: sub('[0-9]{4}','2019',m)
if findall('[0-9]{4}',m)
else sub('[0-9]{2}','19',m))
</code></pre>
<hr/>
<hr/>
<p>更新:cs95提供了以下简短解决方案:</p>
<pre><code>import pandas as pd
df = pd.DataFrame(...)
df['Col_A'] = df['Col_A'].str.replace('\d{2}(?!\d)', '19')
</code></pre>