Python Dataframe 完整值

Question

我有一个 df 数据框，如下所示:

    Item       Notional
0   .decash    NaN
1   .decash    NaN
2    usdjpy    NaN
3   .decash    NaN
4    usdjpy    NaN

第二个 df1 数据帧如下:

    Item       Notional
0   .decash    10 000
1    usdjpy    100 000

是否可以在没有 for 指令的情况下用 df1.Notional 填充 df.Notional？

Answer 1

In [33]: df['Notional'] = df.Item.map(df1.set_index('Item').Notional)

In [34]: df
Out[34]:
      Item  Notional
0  .decash     10000
1  .decash     10000
2   usdjpy    100000
3  .decash     10000
4   usdjpy    100000

或者:

In [36]: df.drop('Notional',1).merge(df1, on='Item', how='left')
Out[36]:
      Item  Notional
0  .decash     10000
1  .decash     10000
2   usdjpy    100000
3  .decash     10000
4   usdjpy    100000