I get a KeyError when merging two data frames, even though I have confirmed that both have dt as a name and both are of the same data type.
df_hown.head() Out[118]: dt hown_rt 0 1980-01-01 65.5 1 1980-04-01 65.6 2 1980-07-01 65.6 3 1980-10-01 65.6 4 1981-01-01 65.6 df_vcy.head() Out[119]: dt vcy_rt 0 1956-01-01 6.2 1 1956-04-01 5.9 2 1956-07-01 6.3 3 1956-10-01 5.8 4 1957-01-01 5.3 df_hown.dtypes Out[132]: dt object hown_rt float64 dtype: object df_vcy.dtypes Out[133]: dt object vcy_rt float64 dtype: object # merge dataframes to create new one df_merged = pd.merge(df_hown, df_vcy[['vcy_rt']], on=['dt','dt']) ... KeyError: 'dt'