4
比方說,我有一個分類變量和值時間序列數據幀:在大熊貓的興趣行之前和之後選擇行
In [4]: df = pd.DataFrame(data={'category': np.random.choice(['A', 'B', 'C', 'D'], 11), 'value': np.random.rand(11)}, index=pd.date_range('2015-04-20','2015-04-30'))
In [5]: df
Out[5]:
category value
2015-04-20 D 0.220804
2015-04-21 A 0.992445
2015-04-22 A 0.743648
2015-04-23 B 0.337535
2015-04-24 B 0.747340
2015-04-25 B 0.839823
2015-04-26 D 0.292628
2015-04-27 D 0.906340
2015-04-28 B 0.244044
2015-04-29 A 0.070764
2015-04-30 D 0.132221
如果我感興趣的是與A類行,過濾分離他們是微不足道的。但如果我對類別A之前的n行感興趣呢?如果n = 2,我想看到的東西,如:
In [5]: df[some boolean indexing]
Out[5]:
category value
2015-04-20 D 0.220804
2015-04-21 A 0.992445
2015-04-22 A 0.743648
2015-04-27 D 0.906340
2015-04-28 B 0.244044
2015-04-29 A 0.070764
同樣,如果我感興趣的n行各地 A類的?再次如果n = 2,我想看到這個:
In [5]: df[some other boolean indexing]
Out[5]:
category value
2015-04-20 D 0.220804
2015-04-21 A 0.992445
2015-04-22 A 0.743648
2015-04-23 B 0.337535
2015-04-24 B 0.747340
2015-04-27 D 0.906340
2015-04-28 B 0.244044
2015-04-29 A 0.070764
2015-04-30 D 0.132221
謝謝!
你可能會有所幫助:http://stackoverflow.com/questions/28837633/pandas-get-position-of-a-given-指數在非數據幀 –