import pandas as pd tokyo = pd.DataFrame(data={'year':['2013','2014','2015'], 'cnt':[10,15,20], 'price':[100,100,90],}, columns=['year','cnt','price']) osaka = pd.DataFrame(data={'year':['2013','2014','2015'], 'cnt':[5,6,7], 'price':[100,100,100],}, columns=['year','cnt','price']) yokohama = pd.DataFrame(data={'year':['2015'], 'cnt':[1], 'price':[50],}, columns=['year','cnt','price']) tokyo ------