Python 合并多个数据帧-一些具有共享唯一ID，一些具有共享列

好的，熊猫和蟒蛇相对来说比较陌生，所以如果我的问题非常明显，请道歉。浏览了所有关于合并、加入和连接的熊猫文档，通读了Stackoverflow和Scriptscoop上的所有类似问题，并在YouTube上观看了数小时的熊猫教程。但我还没有弄清楚如何做我想做的事情，这在熊猫身上似乎相对容易

基本上，我对每种阳性细菌结果（大肠杆菌、金黄色葡萄球菌等）都有一个数据框架。在数据框中，有一个与患者关联的唯一ID（医嘱），以及结果、日期和病房名称。一名患者可能只对一种细菌呈阳性，也可能对多种细菌呈阳性，因此数据帧之间的一些订单号重叠，有些订单号只显示一次

例如：

    Order  Test_EC  Results_EC     Date     Ward Name
0   K70201  E. coli  MODERATE   2014-01-02    North
1   K70277  E. coli  MODERATE   2014-01-02    North
2   K70205  E. coli  FEW        2014-01-02    West
3   K70818  E. coli  MODERATE   2014-01-03    South
4   K70202  E. coli  FEW        2014-01-03    West
5   K80070  E. coli  RARE       2014-01-03    North
6   K80666  E. coli  FEW        2014-01-03    East

    Order   Test_SA  Results_SA    Date     Ward Name
0   K80766  S.aureus MANY       2014-01-01    West
1   K70201  S.aureus MANY       2014-01-02    North
2   K70277  S.aureus MANY       2014-01-02    North
3   K70205  S.aureus FEW        2014-01-02    West
4   K90107  S.aureus FEW        2014-01-06    North

我想根据患者的医嘱号创建一个主数据库，为每个阳性检测和结果以及日期和病房名称创建一个相关列。如果患者一项检查呈阳性，另一项检查呈阴性，则可以进行NaN填充。如果来自不同数据帧的两个订单号匹配，那么根据定义，它们将具有相同的日期和病房名称，因此基本上测试和结果列将是唯一的新信息

简而言之，我希望维护每个表中包含的所有信息，同时将每个订单号的所有关联数据显示在一行中。

我希望得到这样的东西：

    Order   Test_EC Results_EC  Test_SA Results_SA     Date  Ward Name
0   K70201  E. coli MODERATE    S.aureus MANY      2014-01-02 North
1   K70277  E. coli MODERATE    S.aureus MANY      2014-01-02 North
2   K70205  E. coli FEW         S.aureus FEW       2014-01-02 West
3   K70818  E. coli MODERATE    NaN      NaN       2014-01-03 South
4   K70202  E. coli FEW         NaN      NaN       2014-01-03 West
5   K80070  E. coli RARE        NaN      NaN       2014-01-03 North
6   K80666  E. coli FEW         NaN      NaN       2014-01-03 East
7   K80766  NaN     NaN         S.aureus MANY      2014-01-01 West
8   K90107  NaN     NaN         S.aureus FEW       2014-01-06 North

如您所见，结果数据框缩短了三行，因为有三名患者同时感染了大肠杆菌和金黄色葡萄球菌。order列中没有重复的值，但所有信息都已保存

我还想继续建立这样一个数据库，用不同的细菌做同样的事情20多次。实际数据集约为100000个唯一订单号

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如果我浏览了我尝试过的各种连接、合并和concat函数的组合，以及它们不起作用的原因，那么这篇文章就太长了。我知道我错过了一些明显的东西。任何想法都将不胜感激

看起来您想要“外部”合并

In [154]: df1
Out[154]: 
    Order  Test_EC Results_EC        Date Ward Name
0  K70201  E. coli   MODERATE  2014-01-02     North
1  K70277  E. coli   MODERATE  2014-01-02     North
2  K70205  E. coli        FEW  2014-01-02      West
3  K70818  E. coli   MODERATE  2014-01-03     South
4  K70202  E. coli        FEW  2014-01-03      West
5  K80070  E. coli       RARE  2014-01-03     North
6  K80666  E. coli        FEW  2014-01-03      East

In [155]: df2
Out[155]: 
    Order   Test_SA Results_SA        Date Ward Name
0  K80766  S.aureus       MANY  2014-01-01      West
1  K70201  S.aureus       MANY  2014-01-02     North
2  K70277  S.aureus       MANY  2014-01-02     North
3  K70205  S.aureus        FEW  2014-01-02      West
4  K90107  S.aureus        FEW  2014-01-06     North

In [156]: df1.merge(df2, how='outer')
Out[156]: 
    Order  Test_EC Results_EC        Date Ward Name   Test_SA Results_SA
0  K70201  E. coli   MODERATE  2014-01-02     North  S.aureus       MANY
1  K70277  E. coli   MODERATE  2014-01-02     North  S.aureus       MANY
2  K70205  E. coli        FEW  2014-01-02      West  S.aureus        FEW
3  K70818  E. coli   MODERATE  2014-01-03     South       NaN        NaN
4  K70202  E. coli        FEW  2014-01-03      West       NaN        NaN
5  K80070  E. coli       RARE  2014-01-03     North       NaN        NaN
6  K80666  E. coli        FEW  2014-01-03      East       NaN        NaN
7  K80766      NaN        NaN  2014-01-01      West  S.aureus       MANY
8  K90107      NaN        NaN  2014-01-06     North  S.aureus        FEW

嗯，是的！merge（df2，on=['Order'、'Date'、'wardname']，how='outer'）似乎工作得很好。不知道为什么我会有这么多麻烦。谢谢你的帮助！