Python：连接两个数据帧的行，其中并非所有列都相同

Question

我有两个数据框：

编辑：

df1 = pd.DataFrame(index = [0,1,2], columns=['timestamp', 'order_id', 'account_id', 'USD', 'CAD'])
df1['timestamp']=['2022-01-01','2022-01-02','2022-01-03']
df1['account_id']=['usdcad','usdcad','usdcad']
df1['order_id']=['11233123','12313213','12341242']
df1['USD'] = [1,2,3]
df1['CAD'] = [4,5,6]
df1:
    timestamp   account_id order_id  USD CAD
0   2022-01-01  usdcad     11233123  1   4
1   2022-01-02  usdcad     12313213  2   5
2   2022-01-03  usdcad     12341242  3   6

df2 = pd.DataFrame(index = [0,1], columns = ['timestamp','account_id', 'currency','balance'])
df2['timestamp']=['2021-12-21','2021-12-21']
df2['account_id']=['usdcad','usdcad']
df2['currency'] = ['USD', 'CAD']
df2['balance'] = [2,3]
df2:
    timestamp  account_id currency  balance
0   2021-12-21 usdcad     USD       2
1   2021-12-21 usdcad     CAD       3

我想在索引 0 处向 df1 添加一行，并根据货币用 df2 的余额填充该行。所以最终的 df 应该是这样的：

df:
    timestamp   account_id order_id  USD CAD
0   0           0          0         2   3
1   2022-01-01  usdcad     11233123  1   4
2   2022-01-02  usdcad     12313213  2   5
3   2022-01-03  usdcad     12341242  3   6

我怎样才能用 pythonic 方式做到这一点？谢谢

Answer 1

将 df2 的索引设置为 currency 然后将索引转置为列，然后将此数据框附加 df1

df_out = df2.set_index('currency').T.append(df1, ignore_index=True).fillna(0)

print(df_out)

   USD  CAD  order_id
0    2    3         0
1    1    4  11233123
2    2    5  12313213
3    3    6  12341242

Python：连接两个数据帧的行，其中并非所有列都相同

Python: concat rows of two dataframes where not all columns are the same

python

dataframe

pandas

reindex