The knitr package was designed to be a transparent engine for dynamic report generation with R, solve some long-standing problems in Sweave, and combine features in other add-on packages into one package (knitr ≈ Sweave + cacheSweave + pgfSweave + weaver + animation::saveLatex + R2HTML::RweaveHTML + highlight::HighlightWeaveLatex + 0.2 * brew + 0.1 * SweaveListingUtils + more).

• Transparency means that the user has full access to every piece of the input and output, e.g., 1 + 2 produces [1] 3 in an R terminal, and knitr can let the user decide whether to put 1 + 2 between \begin{verbatim} and \end{verbatim}, or <div class="rsource"> and </div>, and put [1] 3 in \begin{Routput} and \end{Routput}; see the hooks page for details
• knitr tries to be consistent with users’ expectations by running R code as if it were pasted in an R terminal, e.g., qplot(x, y) directly produces the plot (no need to print() it), and all the plots in a code chunk will be written to the output by default
• Packages like pgfSweave and cacheSweave have added useful features to Sweave (high-quality tikz graphics and cache), and knitr has simplified the implementations
• The design of knitr allows any input languages (e.g. R, Python and awk) and any output markup languages (e.g. LaTeX, HTML, Markdown, AsciiDoc, and reStructuredText)

This package is developed on GitHub; for installation instructions and FAQ’s, see README. This website serves as the full documentation of knitr, and you can find the main manual, the graphics manual and other demos / examples here. For a more organized reference, see the knitr book.