擅长:python、mysql、java
<pre><code>In [11]: df.groupby('user_id', as_index=False).agg(lambda col: set(col.values.tolist()))
Out[11]:
user_id class_type instructor
0 1 {Krav Maga, Ju-jitsu} {Alice, Bob}
1 2 {Yoga, Krav Maga} {Alice}
2 3 {Ju-jitsu, Karate} {Bob}
3 4 {Krav Maga} {Alice}
</code></pre>
<p>或@jezrael的较短版本:</p>
<pre><code>In [12]: df.groupby('user_id').agg(lambda x: set(x))
Out[12]:
class_type instructor
user_id
1 {Krav Maga, Ju-jitsu} {Alice, Bob}
2 {Yoga, Krav Maga} {Alice}
3 {Ju-jitsu, Karate} {Bob}
4 {Krav Maga} {Alice}
</code></pre>