擅长:python、mysql、java
<p><code>Split</code>并应用<code>set</code>和{<cd3>},即</p>
<pre><code>df['y'].str.split(', ').apply(set).str.join(', ')
0 us, ec, gbr, lst
1 us, ec
2 us, ec, gbr, lst
3 us, ec, ir
4 us, lst, ec, gbr, chn
Name: y, dtype: object
</code></pre>
<p>根据评论更新:</p>
^{pr2}$