Answers for "how to merge two dataframes using multiple keys"

how to merge dataframe with different keys

pandas.merge(df1, df2, how='left', left_on=['id_key'], right_on=['fk_key'])

pandas merge multiple dataframes

import pandas as pd
from functools import reduce

# compile the list of dataframes you want to merge
data_frames = [df1, df2, df3]
df_merged = reduce(lambda  left,right: pd.merge(left,right,on=['key_col'],
                                            how='outer'), data_frames)