基于多个重叠合并两个数据框

Question

I have two dataframes, each consisting of 3 columns with Year, Month and Day. df1 contains several other values that correspond to each date, and df2 contains different values. I want to merge both of the dataframes into one where the year, month and day are all in common. However, my first dataset goes from 1979-2017, but doesn't include all days or months 7-9. The second dataframe goes from 1979-2017 and includes every single day.

df1:

Year    Month    Day    IVT    IWV   Morevalues...
1979    1        10     275    21
1979    1        12     365    22
1979    1        16     565    29

df2:

Year    Month    Day    NAO    PNA 
1979    1        9      1.2    0.76
1979    1        10     1.1    0.85
1979    1        11     1.15   0.82
1979    1        12     1.13   0.83

What I want:

Year    Month    Day    IVT    IWV    NAO    PNA
1979    1        10     275    21     1.1    0.85
1979    1        12     365    22     1.13   0.83

Answer 1

尝试这个：

res = pd.merge(df1, df2, how='inner', on=['Year', 'Month', 'Day'])