The following references give helpful introductions to python:

• The official python tutorial

• The software carpentry python lessons

Some resources for practicing on your own:

• Code Academy python rack: step-by-step tutorial through the basics of the language

• Project Euler: a set of increasingly complex programming tasks to try out with python

• Think python

• Dive into Python

• SciPy Lecture Notes

• Google's python class

• more resources can be found at: http://pythonbooks.revolunet.com/

• Astronomy: AstroPy

• Atmospheric sciences: PyAOS

• Biology: Biopython

• Ocean and marine sciences: OceanPython

• Psychology resources: PyschoPy

• Quantum physics: QuTiP

• Solar physics: SunPy