熊猫据帧片有太多层次

Question

我有一个数据帧是一个从一个更大的数据帧切片：

df 
Out[47]: 
          price log_price dlog_price 
data_source_id trade_date        
1    2014-03-05 174.4 5.161352 -2.089993 

正如你所看到的，数据帧具有1行中它。

然而，该指数有千万级别的，因为这些似乎仍然从父在那里：

df.index 
Out[48]: 
MultiIndex(levels=[[1, 2, 4, 5, 6, 7, 8, 9], [1990-01-01 00:00:00, 1990-01-02 00:00:00, 1990-01-03 00:00:00, 1990-01-04 00:00:00, 1990-01-05 00:00:00, 1990-01-08 00:00:00, 1990-01-09 00:00:00, 1990-01-10 00:00:00, 1990-01-11 00:00:00, 1990-01-12 00:00:00, 1990-01-15 00:00:00, 1990-01-16 00:00:00, 1990-01-17 00:00:00, 1990-01-18 00:00:00, 1990-01-19 00:00:00, 1990-01-22 00:00:00, 1990-01-23 00:00:00, 1990-01-24 00:00:00, 1990-01-25 00:00:00, 1990-01-26 00:00:00, 1990-01-29 00:00:00, 1990-01-30 00:00:00, 1990-01-31 00:00:00, 1990-02-01 00:00:00, 1990-02-02 00:00:00, 1990-02-05 00:00:00, 1990-02-06 00:00:00, 1990-02-07 00:00:00, 1990-02-08 00:00:00, 1990-02-09 00:00:00, 1990-02-12 00:00:00, 1990-02-13 00:00:00, 1990-02-14 00:00:00, 1990-02-15 00:00:00, 1990-02-16 00:00:00, 1990-02-19 00:00:00, 1990-02-20 00:00:00, 1990-02-21 00:00:00, 1990-02-22 00:00:00, 1990-02-23 00:00:00, 1990-02-26 00:00:00, 1990-02-27 00:00:00, 1990-02-28 00:00:00, 1990-03-01 00:00:00, 1990-03-02 00:00:00, 1990-03-05 00:00:00, 1990-03-06 00:00:00, 1990-03-07 00:00:00, 1990-03-08 00:00:00, 1990-03-09 00:00:00, 1990-03-12 00:00:00, 1990-03-13 00:00:00, 1990-03-14 00:00:00, 1990-03-15 00:00:00, 1990-03-16 00:00:00, 1990-03-19 00:00:00, 1990-03-20 00:00:00, 1990-03-21 00:00:00, 1990-03-22 00:00:00, 1990-03-23 00:00:00, 1990-03-26 00:00:00, 1990-03-27 00:00:00, 1990-03-28 00:00:00, 1990-03-29 00:00:00, 1990-03-30 00:00:00, 1990-04-02 00:00:00, 1990-04-03 00:00:00, 1990-04-04 00:00:00, 1990-04-05 00:00:00, 1990-04-06 00:00:00, 1990-04-09 00:00:00, 1990-04-10 00:00:00, 1990-04-11 00:00:00, 1990-04-12 00:00:00, 1990-04-13 00:00:00, 1990-04-16 00:00:00, 1990-04-17 00:00:00, 1990-04-18 00:00:00, 1990-04-19 00:00:00, 1990-04-20 00:00:00, 1990-04-23 00:00:00, 1990-04-24 00:00:00, 1990-04-25 00:00:00, 1990-04-26 00:00:00, 1990-04-27 00:00:00, 1990-04-30 00:00:00, 1990-05-01 00:00:00, 1990-05-02 00:00:00, 1990-05-03 00:00:00, 1990-05-04 00:00:00, 1990-05-07 00:00:00, 1990-05-08 00:00:00, 1990-05-09 00:00:00, 1990-05-10 00:00:00, 1990-05-11 00:00:00, 1990-05-14 00:00:00, 1990-05-15 00:00:00, 1990-05-16 00:00:00, 1990-05-17 00:00:00, 1990-05-18 00:00:00, ...]], 
      labels=[[0], [6308]], 
      names=['data_source_id', 'trade_date']) 

我如何收拾多指数，所以它不会有这么多的水平？

这似乎是工作，但它是一个有点乱：

df2 = df.reset_index().set_index(df.index.names) 

df2.index 
Out[53]: 
MultiIndex(levels=[[1], [2014-03-05 00:00:00]], 
      labels=[[0], [0]], 
      names=['data_source_id', 'trade_date']) 

Answer 1

你可以这样做：

df.index = pd.MultiIndex.from_tuples(df.index.values, names=df.index.names) 

或者：

>>> arr = list(map(df.index.get_level_values, range(df.index.nlevels))) 
>>> df.index = pd.MultiIndex.from_arrays(arr)