Hi! I have 2 questions about the pd.merge() here
Screen Link: https://app.dataquest.io/m/468/business-metrics/7/date-wrangling
1, The right_index=True
seems to reset index for a table, but it is used for which table here, for churn or monthly_churn, it looks like to the monthly_churn. but we did not clarify to python, how did python know how to work?
2, we learned pd.merge()
in below format before. but it shows error. 'yearmonth'
why?
Thank you!!
My Code:
churn = pd.merge(left=churn, right=monthly_churn, how="left", on="yearmonth", right_index=True)