擅长:python、mysql、java
<pre><code>In [200]: df
Out[200]:
col1 col2
0 animal cat;dog;cat
1 animal dog
2 animal fish
3 color black;green
4 color red
In [201]: (df.set_index('col1')
.col2.str.split(';', expand=True)
.stack()
.reset_index(level=1, drop=True)
.reset_index(name='col2'))
Out[201]:
col1 col2
0 animal cat
1 animal dog
2 animal cat
3 animal dog
4 animal fish
5 color black
6 color green
7 color red
</code></pre>