https://bitbucket.org/tavisrudd/r_users_group_1/src https://bitbucket.org/tavisrudd/r_users_group_1/get/tip.zip https://bitbucket.org/tavisrudd/r_users_group_1/get/tip.tar.gz
Data management, analysis and visualization in general
thousands of libraries http://crantastic.org/ http://cran.r-project.org/ Lots of interesting blogs: http://www.r-bloggers.com/ http://learnr.wordpress.com/
… but there are higher order functions that make it very efficient and easy.
this.is.just.a.variable.name this_is_a_valid_varname for modern versions of R, but wasn’t in the past
Preferably your own data from real life projects, but there is plenty of interesting CSV data on the web if you can’t use your own.