Pandas DENSE RANK

I’m dealing with pandas dataframe and have a frame like this:

Year Value  
2012  10
2013  20
2013  25
2014  30

I want to make an equialent to DENSE_RANK () over (order by year) function. to make an additional column like this:

    Year Value Rank
    2012  10    1
    2013  20    2
    2013  25    2
    2014  30    3

How can it be done in pandas?

Thanks!

Answer

Use pd.Series.rank with method='dense'

df['Rank'] = df.Year.rank(method='dense').astype(int)

df