我有DataFrame
MultiIndex
。索引字段为OptionSymbol
(级别0)和QuoteDatetime
(级别1)。我已对DataFrame
进行索引和排序,如下所示:
sorted = df.sort_values(
['OptionSymbol', 'QuoteDatetime'],
ascending=[False, True]
)
indexed = sorted.set_index(
['OptionSymbol', 'QuoteDatetime'],
drop=True
)
这导致以下结果:
Id Strike Expiration OptionType
OptionSymbol QuoteDatetime
ZBYMZ 2013-09-02 234669 170.0 2011-01-22 put
2013-09-03 234901 170.0 2011-01-22 put
2013-09-04 235133 170.0 2011-01-22 put
... ... ... ... ... ...
YBWNA 2010-02-12 262202 95.0 2010-02-20 call
2010-02-16 262454 95.0 2010-02-20 call
2010-02-17 262707 95.0 2010-02-20 call
... ... ... ... ... ...
XWNAX 2012-07-12 262201 90.0 2010-02-20 call
2012-07-16 262453 90.0 2010-02-20 call
2012-07-17 262706 90.0 2010-02-20 call
... ... ... ... ... ...
WWWAX 2012-04-12 262201 90.0 2010-02-20 call
2012-04-16 262453 90.0 2010-02-20 call
2012-04-17 262706 90.0 2010-02-20 call
... ... ... ... ... ...
正如预期的那样,首先按OptionSymbol
的降序排序,然后在OptionSymbol
组中按升序排序。
我需要做的是现在使用QuoteDatetime
中的第一个值,因此结果如下所示:
Id Strike Expiration OptionType
OptionSymbol QuoteDatetime
XBWNA 2010-02-12 262202 95.0 2010-02-20 call
2010-02-16 262454 95.0 2010-02-20 call
2010-02-17 262707 95.0 2010-02-20 call
... ... ... ... ... ...
NWWAX 2012-04-12 262201 90.0 2010-02-20 call
2012-04-16 262453 90.0 2010-02-20 call
2012-04-17 262706 90.0 2010-02-20 call
... ... ... ... ... ...
BWNAX 2012-07-12 262201 90.0 2010-02-20 call
2012-07-16 262453 90.0 2010-02-20 call
2012-07-17 262706 90.0 2010-02-20 call
... ... ... ... ... ...
XBYMZ 2013-09-02 234669 170.0 2011-01-22 put
2013-09-03 234901 170.0 2011-01-22 put
2013-09-04 235133 170.0 2011-01-22 put
... ... ... ... ... ...
我尝试过各种各种方法来索引= 1然后我失去了OptionSymbol
组。我怎么做这种呢?
from collections import OrderedDict
df = OrderedDict((
('OptionSymbol', pd.Series(['ZBYMZ', 'ZBYMZ', 'ZBYMZ', 'YBWNA', 'YBWNA', 'YBWNA', 'XWNAX', 'XWNAX', 'XWNAX', 'WWWAX', 'WWWAX', 'WWWAX', ])),
('QuoteDatetime', pd.Series(['2013-09-02', '2013-09-03', '2013-09-04', '2010-02-12', '2010-02-16', '2010-02-17', '2012-07-12', '2012-07-16', '2012-07-17', '2012-04-12', '2012-04-16', '2012-04-17'])),
('Id', pd.Series(np.random.randn(12,))),
('Strike', pd.Series(np.random.randn(12,))),
('Expiration', pd.Series(np.random.randn(12,))),
('OptionType', pd.Series(np.random.randn(12,)))
))
在这种情况下使用df.sort_index(level=1)
的奇怪工作可以解决我的完整数据集(20多列),但我失去了OptionSymbol
分组。
答案 0 :(得分:2)
IIUC您只需按第二级排序索引:
In [27]: df.sort_index(level=1)
Out[27]:
Id Strike Expiration OptionType
OptionSymbol QuoteDatetime
YBWNA 2010-02-12 262202 95.0 2010-02-20 call
2010-02-16 262454 95.0 2010-02-20 call
2010-02-17 262707 95.0 2010-02-20 call
WWWAX 2012-04-12 262201 90.0 2010-02-20 call
2012-04-16 262453 90.0 2010-02-20 call
2012-04-17 262706 90.0 2010-02-20 call
XWNAX 2012-07-12 262201 90.0 2010-02-20 call
2012-07-16 262453 90.0 2010-02-20 call
2012-07-17 262706 90.0 2010-02-20 call
ZBYMZ 2013-09-02 234669 170.0 2011-01-22 put
2013-09-03 234901 170.0 2011-01-22 put
2013-09-04 235133 170.0 2011-01-22 put