version1

this is based on question in "CS194-16 Introduction to Data Science" course of UC berkley. For the exact question or clearify problem statement visit http://nbviewer.ipython.org/github/amplab/datascience-sp14/blob/master/hw2/HW2.ipynb.

The data i use of lastfm can be downloaded through https://github.com/amplab/datascience-sp14/raw/master/hw2/hw2data.tar.gz