joined_df = pd.merge(mydf, mylookup, left_on= "OP_UNIQUE_CARRIER", right_on="Code") joined_df.head(10) If we run these lines in the Python 3 console, we get: martinheller@Martins-Retina-MacBook ...

Python’s new template strings, or t-strings ... output.append(item) return "".join(output) If we ran t_upper() on the above template, we would get Hello, DAVIS as the output.