擅长:python、mysql、java
<p>另一种方式</p>
<pre><code>#pad df.hour with 0 on the left
s=df.hour.str.pad(width=2, side='left', fillchar='0')
#concat using df.str.cat
df['datetime']=pd.to_datetime(df['date'].str.cat(s+":00:00", sep=' '))
date hour datetime
0 2020-07-20 1 2020-07-20 01:00:00
1 2020-07-20 2 2020-07-20 02:00:00
2 2020-07-20 3 2020-07-20 03:00:00
3 2020-07-20 4 2020-07-20 04:00:00
</code></pre>