掌握大熊猫面板布尔索引错误

Question

我有一个面板stocks具有['volume'], ['30_Avg_Vol'] and ['20_Avg_Vol']作为轴

stocks.Volume 
        AAPL  OPK 
Date        
010-01-11 115557365.0 130195.0 
2010-01-12 148614774.0 121245.0 
2010-01-13 151472335.0 47897.0 
2010-01-14 108288411.0 126539.0 
2010-01-15 148584065.0 175261.0 
2010-01-19 182501620.0 123318.0 
2010-01-20 153037892.0 100803.0 
2010-01-21 152038565.0 262285.0 
2010-01-22 220441872.0 114525.0 


stocks['30_Avg_Vol'] 
Date    AAPL   OPK 
2010-01-21   NaN   NaN 
2010-01-22   NaN   NaN 
2010-01-25 1.526774e+08 1.607402e+05 
2010-01-26 1.723086e+08 1.592968e+05 
2010-01-27 1.875047e+08 1.554605e+05 
2010-01-28 1.933864e+08 1.540021e+05 
2010-01-29 1.996023e+08 1.549712e+05 
2010-02-01 1.989956e+08 1.532240e+05 

stocks['20_Avg_Vol'] 
        AAPL   OPK 
Date       
2010-01-12   NaN   NaN 
2010-01-13   NaN   NaN 
2010-01-14   NaN   NaN 
2010-01-15 1.315716e+08 1.718937e+05 
2010-01-19 1.362016e+08 1.674777e+05 
2010-01-20 1.376046e+08 1.619215e+05 
2010-01-21 1.387149e+08 1.696418e+05 
2010-01-22 1.445526e+08 1.657049e+05 
2010-01-25 1.526774e+08 1.607402e+05 
2010-01-26 1.723086e+08 1.592968e+05 
2010-01-27 1.875047e+08 1.554605e+05 

我想裁板以下列方式

stocks[(stocks['Volume']> (1.5 * stocks['30_Avg_Vol']))|(stocks['Volume']> (1.5* stocks['20_Avg_Vol']))] 

无论中，成交量大于平均交易量30天或平均交易量20天的1.5倍。

，但我发现了以下错误：

raise ValueError('Cannot index with multidimensional key') 
ValueError: Cannot index with multidimensional key 

围绕这个办法吗？

谢谢。

Answer 1

您有MultiIndex。要索引到MultiIndex，您必须成对指定您的密钥（或以三元组形式，等等）。

来解决这个问题最简单的办法是重置到一个单一的指标：

所以：

stocks[(stocks['Volume']> (1.5 * stocks['30_Avg_Vol']))|(stocks['Volume']> (1.5* stocks['20_Avg_Vol']))] 

变为：

_stocks = stocks.reset_index() 

_stocks[(_stocks['Volume']> (1.5 * _stocks['30_Avg_Vol']))|(_stocks['Volume']> (1.5* _stocks['20_Avg_Vol']))]