Downloadable reports with knitr

This same function can very easily allow your users to produce custom reports in HTML, pdf, or MS Word ready to be downloaded to their machines, using the knitr package (http://yihui.name/knitr/). Knitr is a user-contributed package that allows reports to be generated dynamically from a mixture of a static report format interleaved with the output from R.

So, for example, titles and text can be fixed, but each time the report is run, different outputs will be produced within the document depending on the state of the data when the output is generated. Knitr can be used with the RMarkdown format described in Chapter 2, Building Your First Application. Here is the simple RMarkdown document within the Google Analytics application:

# Summary report
## Text summary
This report summarises data between `r strftime(input$dateRange[1], format = "%d %B %Y")` and `r strftime(input$dateRange[2], format = "%d %B %Y")`.

## Trend graph
```{r fig.width=7, fig.height=6, echo...