import pandas as pd

df1 = pd.DataFrame(
    {
        "HPI": [80, 86, 88, 85],
        "Int_rate": [2, 3, 2, 2],
        "US_GDP_Thousands": [50, 55, 65, 55],
        "Year": [2001, 2002, 2003, 2005],
    }
)

"""
df2 = pd.DataFrame({'HPI':[80,85,88,85],
                    'Int_rate':[5, 3, 2, 2],
                    'US_GDP_Thousands':[50, 55, 65, 55]},
                   index = [2005, 2006, 2007, 2008])
"""

df3 = pd.DataFrame(
    {
        "HPI": [95, 86, 88, 90],
        "Unemployment": [7, 8, 9, 6],
        "Low_tier_HPI": [50, 52, 50, 53],
        "Year": [2000, 2002, 2003, 2004],
    }
)


# print(pd.merge(df1, df3, on=['HPI']))
# print(df1)
# print(df3)

# df1.set_index('Year', inplace=True)
# df3.set_index('Year', inplace=True)


merged = pd.merge(df1, df3, on="Year", how="outer")
print(merged)