大熊貓據幀獲得每日數據

Question

我有時間戳作爲指數大熊貓數據幀：

我想將它轉換爲獲得日常值的數據幀，但不必重新採樣原始數據框（無總計或平均小時數據）。理想情況下，我想每天獲得24個日常值，例如：

是否有一種方法可以快速執行此操作？

謝謝！

Answer 1

IIUC可以groupby對索引的date屬性，然後應用聚合的值到列表的拉姆達：

In [21]: 
# generate some data 
df = pd.DataFrame({'GFS_rad':np.random.randn(100), 'GFS_tmp':np.random.randn(100)}, index=pd.date_range(dt.datetime(2016,1,1), freq='1h', periods=100)) 
df.groupby(df.index.date)['GFS_rad','GFS_tmp'].agg(lambda x: [x['GFS_rad'].values,x['GFS_tmp'].values]) 

Out[21]: 
                 GFS_rad \ 
2016-01-01 [-0.324115177542, 1.59297335764, 0.58118555943... 
2016-01-02 [-0.0547016526463, -1.10093451797, -1.55790161... 
2016-01-03 [-0.34751220092, 1.06246918632, 0.181218794826... 
2016-01-04 [0.950977469848, 0.422905080529, 1.98339145764... 
2016-01-05 [-0.405124861624, 0.141470757613, -0.191169333... 

                 GFS_tmp 
2016-01-01 [-2.36889710412, -0.557972678049, -1.293544410... 
2016-01-02 [-0.125562429825, -0.018852674365, -0.96735945... 
2016-01-03 [0.802961514703, -1.68049099535, -0.5116769061... 
2016-01-04 [1.35789157665, 1.37583167965, 0.538638510171,... 
2016-01-05 [-0.297611872638, 1.10546853812, -0.8726761667...