Merging three dataframes with three similar indexes:

I have three dataframes

df1 :
Date           ID        Number     ID2   info_df1
2021-12-11     1         34         36       60
2021-12-10     2         33         35       57
2021-12-09     3         32         34       80
2021-12-08     4         3133       55

df2:
Date           ID        Number     ID2   info_df2
2021-12-10     2         18         20       50
2021-12-11     1         34         36       89
2021-12-10     2         33         35       40
2021-12-09     3         32         34       92

df3:
Date           ID        Number     ID2   info_df3
2021-12-10     2         18         20       57
2021-12-10     2         18         20       63
2021-12-11     1         34         36       52
2021-12-10     2         33         35       33

I need a data frame with info column from df1,df2 and df3 and Date,ID,Number,ID2 as index.

Format of the merged dataframe should consist these columns:

Date ID Number ID2 info_df1 info_df2
info_df3

>Solution :

If you trying to merge the dataframe based on Date, I think what you need is merge function:

mergedDf = df1.merge(df2, on="Date").merge(df3, on="Date");
mergedDf.set_index("ID2", inplace = True)

But if you are trying to merge dataframes based on multiple columns, you can use a list of column names on the on argument:

mergedDf = df1.merge(df2, on=["Date", "ID", "ID2"]).merge(df3, on=["Date", "ID", "ID2"]);
mergedDf.set_index("ID2", inplace = True)