这是我的问题:
这是我的DataFrame的示例(实际上是从2002年到2012年)
df = pd.DataFrame(
{'Date':["2002-07-31","2002-07-31","2002-07-31","2002-07-31","2002-07-31","2002-08-31","2002-08-31","2002-08-31","2002-08-31","2002-08-31",'2002-09-30','2002-09-30','2002-09-30','2002-09-30','2002-09-30'],
'Name': ["Paul", "John", "Silvia", "Mike", "Cindy","Paul", "David", "Harry", "Mike", "Britney","Francis", "Michael", "Charlie", "Joe", "Hilary"]})
哪个给这个
Date Name
0 2002-07-31 Paul
1 2002-07-31 John
2 2002-07-31 Silvia
3 2002-07-31 Mike
4 2002-07-31 Cindy
5 2002-08-31 Paul
6 2002-08-31 David
7 2002-08-31 Harry
8 2002-08-31 Mike
9 2002-08-31 Britney
10 2002-09-30 Francis
11 2002-09-30 Michael
12 2002-09-30 Charlie
13 2002-09-30 Joe
14 2002-09-30 Hilary
并且我想通过从2002-07-31到2002-08-30以及从2002-08-31到2002-09-30的所有名称固定来重新采样从Monthly到Daily DataFrame的系列。发生在每个月的月底,因此好像使用ffill()方法进行重新采样)。
我正在寻找的结果是这样的:
Date Name
2002-07-31 Paul
2002-07-31 John
2002-07-31 Silvia
2002-07-31 Mike
2002-07-31 Cindy
2002-08-01 Paul
2002-08-01 John
2002-08-01 Silvia
2002-08-01 Mike
2002-08-01 Cindy
2002-08-02 Paul
2002-08-02 John
2002-08-02 Silvia
2002-08-02 Mike
2002-08-02 Cindy
2002-08-03 Paul
2002-08-03 John
2002-08-03 Silvia
2002-08-03 Mike
2002-08-03 Cindy
.....
2002-08-31 Paul
2002-08-31 David
2002-08-31 Harry
2002-08-31 Mike
2002-08-31 Britney
2002-09-01 Paul
2002-09-01 David
2002-09-01 Harry
2002-09-01 Mike
2002-09-01 Britney
....
2002-09-30 Francis
2002-09-30 Michael
2002-09-30 Charlie
2002-09-30 Joe
2002-09-30 Hilary
如您所见,名称仅在每个月底更改。对我来说,最困难的步骤是我选择了5个名称,但我真的不知道如何重新采样到每日数据框,而每天仍然有5个名称。
我已经看过此链接
Resampling Error : cannot reindex a non-unique index with a method or limit
但是这不是真正的相同的问题,我仍然找不到任何解决方案来管理我的问题。如果您有任何想法,欢迎您!
首先,确保您的Date
列是datetime
对象:
df['Date'] = df.Date.astype('datetime64')
然后,按Date
列分组,将名称聚合为list
,执行explode
以扩展名称的list
:
df.groupby('Date').agg(list).resample('D').ffill().explode('Name').reset_index()
# Result:
Date Name
0 2002-07-31 Paul
1 2002-07-31 John
2 2002-07-31 Silvia
3 2002-07-31 Mike
4 2002-07-31 Cindy
.. ... ...
305 2002-09-30 Francis
306 2002-09-30 Michael
307 2002-09-30 Charlie
308 2002-09-30 Joe
309 2002-09-30 Hilary
[310 rows x 2 columns]
我将透视数据并使用asfreq
进行数据采样,然后进行堆栈:
(df.assign(group=df.groupby('Date').cumcount())
.set_index(['Date','group'])['Name']
.unstack()
.asfreq('D').ffill()
.unstack()
.reset_index('group',drop=True)
.reset_index(name='Name')
)
输出:
Date Name
0 2002-07-31 Paul
1 2002-07-31 John
2 2002-07-31 Silvia
3 2002-07-31 Mike
4 2002-07-31 Cindy
.. ... ...
305 2002-09-30 Francis
306 2002-09-30 Michael
307 2002-09-30 Charlie
308 2002-09-30 Joe
309 2002-09-30 Hilary
[310 rows x 2 columns]