https://www.datacamp.com/courses/free-introduction-to-r
http://tryr.codeschool.com/
http://swirlstats.com/students.html
https://www.tidyverse.org/
http://r4ds.had.co.nz/
http://www.dataschool.io/dplyr-tutorial-part-2/
http://rpubs.com/bradleyboehmke/data_wrangling
https://cran.r-project.org/web/packages/stringr/vignettes/stringr.html
http://www.cookbook-r.com/Graphs/
https://ggplot2.tidyverse.org
Documentation site: https://radiant-rstats.github.io/docs
In R(studio) enter: help(package = "radiant")
help(package = "radiant")
Blog: http://vnijs.github.io/blog/
http://www.r-bloggers.com/
http://stackoverflow.com/questions/tagged/r
http://www.cookbook-r.com/
http://www.statmethods.net/
http://rpackages.ianhowson.com/
http://www.rdocumentation.org/