Python for Data Science

This short primer on Python is designed to provide a rapid "on-ramp" to enable computer programmers who are already familiar with concepts and constructs in other programming languages learn enough about Python to facilitate the effective use of open-source and proprietary Python-based machine learning and data science tools.
http://nbviewer.ipython.org/github/gumption/Python_for_Data_Science/blob/master/1_Introduction.ipynb