There are lots of R documents and over 3000 R packages. Which documents to start with and which R packages to use are questions faced by many people.
If you are new to R, an Introduction to R can be a good reference to start with, which is available at CRAN website. After that, you may want to know more details about R Language and data access, and they are documented respectively by the R Language Definition and R Data Import/Export at CRAN website.
If you want to use R for data mining, Data Mining with R – Learning by Case Studies is an excellent book to learn from.
Getting lost in over 3000 R packages? Which R packages to use? CRAN Task Views are a good guidance. They provide collections of packages for different tasks. Some task views related to data mining are:
– CRAN Task View: Machine Learning & Statistical Learning,
– CRAN Task View: Cluster Analysis & Finite Mixture Models,
– CRAN Task View: Time Series Analysis,
– CRAN Task View: Multivariate Statistics, and
– CRAN Task View: Analysis of Spatial Data.
If you want to know which R functions and packages can be used for your data mining applications, R Reference Card for Data Mining will be helpful to you, which is available at RDataMining website <http://www.rdatamining.com>. Another useful document at the website is R and Data Mining: Example and Case Studies, which presents many examples on data mining with R.