我有两个数据框df1和df2。
我正在尝试找出执行df1中每一行的映射的最佳方法，我想在{id，time_by_hour中搜索匹配项df2，df2） {1}}然后将df1中的相应值填回df1_final。
以下是df1
Out[100]:
id time_by_min time_by_hour value
0 a 2017-06-30 01:25:00.000 2017-06-30 02:00:00 NaN
1 a 2017-06-30 01:36:32.308 2017-06-30 02:00:00 NaN
2 a 2017-06-30 02:25:00.000 2017-06-30 03:00:00 NaN
3 a 2017-06-30 02:36:32.308 2017-06-30 03:00:00 NaN
4 b 2017-06-30 01:25:00.000 2017-06-30 02:00:00 NaN
5 b 2017-06-30 01:36:32.308 2017-06-30 02:00:00 NaN
6 b 2017-06-30 02:25:00.000 2017-06-30 03:00:00 NaN
df2
Out[101]:
id time_by_hour value
0 a 2017-06-30 02:00:00 100
1 a 2017-06-30 03:00:00 200
2 b 2017-06-30 02:00:00 150
3 b 2017-06-30 03:00:00 30
4 c 2017-06-30 02:00:00 80
5 c 2017-06-30 03:00:00 900
df1_final
Out[102]:
id time_by_min time_by_hour value
0 a 2017-06-30 01:25:00.000 2017-06-30 02:00:00 100
1 a 2017-06-30 01:36:32.308 2017-06-30 02:00:00 100
2 a 2017-06-30 02:25:00.000 2017-06-30 03:00:00 200
3 a 2017-06-30 02:36:32.308 2017-06-30 03:00:00 200
4 b 2017-06-30 01:25:00.000 2017-06-30 02:00:00 150
5 b 2017-06-30 01:36:32.308 2017-06-30 02:00:00 150
6 b 2017-06-30 02:25:00.000 2017-06-30 03:00:00 30
，我希望最终看到它。
提前谢谢！
{{1}}
答案 0 :(得分：2)
您可以查看merge
df1['value']=df1[['time_by_hour','id']].merge(df2,how='left').value