Customization of rpy2 (see comments at https://bitbucket.org/rpy2/rpy2/issue/230/rmagic-specific-conversion)

ipysetup.py

# This is a setup snippet for an ipython notebook.
# It requires the presence of variable 'setup_digest',
# defined in the cell controlling the setup.
if 'setup_digest' not in locals():
    import rpy2
    %load_ext rpy2.ipython

    # pigheaded / slow rpy2 developpers,
    # customize away:
    from rpy2.robjects.conversion import ri2py
    from rpy2.ipython.rmagic import ri2ipython
    ri2ipython.register(rpy2.robjects.Sexp, ri2py)

    # HTML rendering of rpy2 objects
    from rpy2.ipython.html import init_printing, css, HTML
    init_printing()

    print('Setup complete (cell below).')
else:
    print('Setup already performed.')