python - How to group dataframe rows into list in pandas groupby? - Stack Overflow

Sun Jul 12 2020 12:47:16 GMT+0000 (Coordinated Universal Time)

Saved by @david.starobinski

In [3]: df1 = df.groupby('a')['b'].apply(list).reset_index(name='new')
        df1
Out[3]: 
   a        new
0  A     [1, 2]
1  B  [5, 5, 4]
2  C        [6]