The capability of phython to solve problems is increasing day by day and hence wish to get a basic introduction to the language, specifically to solve oceanography problems.
Basically these are two things. If you never worked with Python before I would suggest to have a look into a general introduction. Take a special look into handling loops, arrays and lists and when to use them, it is gonna save you lot's of computational time.
For specific oceanographic applications I usually use some function from the Gibbs Sea Water Package (particularly what's related to the equation of state): https://github.com/TEOS-10/GSW-python This package gave everything I needed besides the general python scripting. For visualization in general and maps matplotlib and basemap do a great job and are pretty straight forward:
Dr. Robert Hetland of Texas A&M University put together a good course on just that subject. His course materials can be found at his git hub page https://github.com/hetland
You should be able to work your way through the material and it will be an introduction to python with a specific focus on oceanography.