I have pre-published my notes on R as a future book at Leanpub titled Learn R …as you learnt your mother tongue.
In the third draft version, published through Leanpub, approximately 85% of the book contents are included.
The PDF of this updated draft of the book is available since this morning at http://leanpub.com/learnr for whatever price you would like to pay for it (including for free).
Status as of 2017-01-17: Added “playground” exercises to the chapter describing ‘ggplot2’, and converted some of the examples earlier part of the main text into these playground items. Added icons to help readers quickly distinguish playground sections, information sections, warnings about things one needs to be specially aware of and boxes with more advanced content. Added to the sections scales and examples in the ‘ggplot2’ chapter details about the use of colors in R and ‘ggplot2’ 2. Removed some redundant examples, and updated the section on plotmath . Added terms to the alphabetical index. Increased line-spacing to avoid uneven spacing with inline code bits.