python-3.x - Pandas :将一列列表聚合成一个列表

Question

我有以下数据框my_df:

name         numbers
----------------------
A             [4,6]
B             [3,7,1,3]
C             [2,5]
D             [1,2,3]

我想将所有数字组合成一个新列表，所以输出应该是:

 new_numbers
---------------
[4,6,3,7,1,3,2,5,1,2,3]

这是我的代码:

def combine_list(my_lists):
    new_list = []
    for x in my_lists:
        new_list.append(x)

    return new_list

new_df = my_df.agg({'numbers': combine_list})

但是 new_df 看起来和原来的一样:

              numbers
----------------------
0             [4,6]
1             [3,7,1,3]
2             [2,5]
3             [1,2,3]

我做错了什么？我如何使 new_df 像:

 new_numbers
---------------
[4,6,3,7,1,3,2,5,1,2,3]

谢谢!

Answer 1

你需要flatten值，然后通过构造函数创建新的 Dataframe:

flatten = [item for sublist in df['numbers'] for item in sublist]

或者:

flatten = np.concatenate(df['numbers'].values).tolist()

或者:

from  itertools import chain

flatten = list(chain.from_iterable(df['numbers'].values.tolist()))

---

df1 = pd.DataFrame({'numbers':[flatten]})

---

print (df1)
                             numbers
0  [4, 6, 3, 7, 1, 3, 2, 5, 1, 2, 3]

时间是here .