The rpy library documentation is your Python gateway to R, and can be found at https://rpy2.bitbucket.io/.
The Grammar of Graphics is described in a book aptly named The Grammar of Graphics, Leland Wilkinson, Springer.
In terms of data structures, similar functionality to R can be found in the pandas library. You can find some tutorials at http://pandas.pydata.org/pandas-docs/dev/tutorials.html. The book, Python for Data Analysis, Wes McKinney, O'Reilly Media, is also an alternative to consider.