python - 如何按给定日期时间索引的日期进行搜索

Question

给定一个 DataFrame，其中索引为 Datetime，如何通过仅匹配日期部分来检索行？

例如:

df1 =

                     A    B    C    D
2011-01-13 16:00:00  344  144  616  73
2011-01-14 16:00:00  346  145  624  74
2011-01-18 16:00:00  339  146  639  77
...

并给出:

df2['Date'] = 

0    2011-01-13
1    2011-01-13
2    2011-01-26
3    2011-02-02
4    2011-02-10
5    2011-03-03
6    2011-03-03
7    2011-06-03
8    2011-05-03
9    2011-06-10
10   2011-08-01
11   2011-08-01
12   2011-12-20

我想要这样的东西:

for indx, row in df2.iterrows():
    print df1.loc[df1.index.date() == row['Date'].date()]

Answer 1

您可以使用to_series , date和 isin :

print df1.index.to_series().dt.date
2011-01-13 16:00:00    2011-01-13
2011-01-14 16:00:00    2011-01-14
2011-01-18 16:00:00    2011-01-18
dtype: object

print df1.index.to_series().dt.date.isin(df2['Date'].dt.date)
Name: Date, dtype: object
2011-01-13 16:00:00     True
2011-01-14 16:00:00    False
2011-01-18 16:00:00    False
dtype: bool

print df1[df1.index.to_series().dt.date.isin(df2['Date'].dt.date)]
                       A    B    C   D
2011-01-13 16:00:00  344  144  616  73

或者也许您需要:

print df1.index.date
[datetime.date(2011, 1, 13) datetime.date(2011, 1, 14)
 datetime.date(2011, 1, 18)]

print df2['Date'].dt.date.isin(df1.index.date)
0      True
1      True
2     False
3     False
4     False
5     False
6     False
7     False
8     False
9     False
10    False
11    False
12    False
Name: Date, dtype: bool

print df2[df2['Date'].dt.date.isin(df1.index.date)]
        Date
0 2011-01-13
1 2011-01-13