Pandas DataFrame.add() - 忽略缺少的列

Question

我有以下两个DataFrame:

>>> history
              above below
asn   country
12345 US          5     4
      MX          6     3
54321 MX          4     5
>>> current
              above below
asn   country
12345 MX          1     0
54321 MX          0     1
      US          1     0

我在historyDataFrame中保持"上方"和"下方"值的运行计数,如下所示:

>>> history = history.add(current, fill_value=0)
>>> history
               above  below
asn   country              
12345 MX         7.0    3.0
      US         5.0    4.0
54321 MX         4.0    6.0
      US         1.0    0.0

只要currentDataFrame 中没有多余的列,这就可以正常工作.但是当我添加一个额外的列时:

>>> current
              above below cruft
asn   country
12345 MX          1     0   999
54321 MX          0     1   999
      US          1     0   999

我得到以下内容:

>>> history = history.add(current, fill_value=0)
>>> history
               above  below cruft
asn   country              
12345 MX         7.0    3.0 999.0
      US         5.0    4.0   NaN
54321 MX         4.0    6.0 999.0
      US         1.0    0.0 999.0

我希望忽略这个额外的列,因为它在两个DataFrame中都不存在.所需的输出只是:

>>> history
               above  below
asn   country              
12345 MX         7.0    3.0
      US         5.0    4.0
54321 MX         4.0    6.0
      US         1.0    0.0

Answer 1

In [27]: history.add(current, fill_value=0)[history.columns]
Out[27]:
               above  below
asn   country
12345 MX         7.0    3.0
      US         5.0    4.0
54321 MX         4.0    6.0
      US         1.0    0.0

Answer 2

这是一种新方式

pd.concat([df1,df2],join ='inner',axis=0).sum(level=[0,1])