Always new software language in one technical activity is difficult, normally a good documentation can help, these are three book to use R software for beginner and for experts:
· “Introduction to the R Project for Statistical Computing for Use at the ITC” by David Rossiter (PDF, 2010-11-21).
· “R for Beginners” by Emmanuel Paradis (PDF,10 pages).
· A Little Book of R for Multivariate Analysis (pdf, 49 pages) is a simple introduction to multivariate analysis using the R statistics software. It covers topics such as reading and plotting multivariate data, principal components analysis, and linear discriminant analysis.
· A Little Book of R for Biomedical Statistics (pdf, 33 pages) is a simple introduction to biomedical statistics using the R statistics software, with sections on relative risks and odds ratios, dose-response analysis, clinical trial design and meta-analysis.
· A Little Book of R for Time Series (pdf, 71 pages) is a simple introduction to time series analysis using the R statistics software (have you spotted the pattern yet?). It includes instruction on how to read and plot time series, time series decomposition, forecasting, and ARIMA models.
All books are free to use, share and remix under a Creative Commons license, and are available:UPDATE: I updated the title, that's only five free books that I think interesting for R, Also there is another one that I forgot Matlab for R programmer I used Matlab from university till now (for me is always easier Matlab, but it is not free), both languages are similar but you always need a help (small tips).