Sorting Pandas Dataframe by order of another index

Question

Say I have two dataframes, df1 and df2 that share the same index. df1 is sorted in the order that I want df2 to be sorted.

df=pd.DataFrame(index=['Arizona','New Mexico', 'Colorado'],columns=['A','B','C'], data=[[1,2,3],[4,5,6],[7,8,9]]) print df              A  B  C Arizona     1  2  3 New Mexico  4  5  6 Colorado    7  8  9   df2=pd.DataFrame(index=['Arizona','Colorado', 'New Mexico'], columns=['D'], data=['Orange','Blue','Green']) print df2                  D Arizona     Orange Colorado      Blue New Mexico   Green 

What is the best / most efficient way of sorting the second dataframe by the index of the first?

One option is just joining them, sorting, and then dropping the columns:

df.join(df2)[['D']]                   D Arizona     Orange New Mexico   Green Colorado      Blue 

Is there a more elegant way of doing this?

Thanks!

Answer 1

reindex would work - be aware that it will create missing values for index values that are in df, but not in df2.

In [18]: df2.reindex(df.index) Out[18]:                   D Arizona     Orange New Mexico   Green Colorado      Blue