The question is quite broad, as OSIsoft has different pieces of software able to integrate with Python or R.
Also, one can interface PI with Python via PI OLEDB, PI ODBC or PI JDBC. I can elaborate on that further if that is an option you are interested in. There are also several posts in the community referencing usage of the PI SDK in Python (see for example this post)
Finally, this seems like a great use case for our upcoming PI Integrator for BI, right Matt Ziegler? That integrator is the first of a series we plan to release for integrating PI data with Big Data/Analytics tools. You can watch this presentation from the UC 2015 for a high-level overview, and that one for a more technical presentation and a demo, and let us know if you have any question.
May I ask where you are with this project? Did any of the suggestions in my previous response help?