8.6 Some tips and tricks

Problem :

When rendering my R markdown document to pdf my code runs off the edge of the page.

Solution:

Add a global_options argument at the start of your .Rmd file in a code chunk:

```{r, global_options, include=FALSE}
knitr::opts_chunk$set(message=FALSE, tidy.opts=list(width.cutoff=60), tidy=TRUE) 
```

This code chunk won’t be displayed in the final document due to the include = FALSE argument and you should place the code chunk immediately after the YAML header to affect everything below that.

tidy.opts = list(width.cutoff = 60), tidy=TRUE defines the margin cutoff point and wraps text to the next line. Play around with this value to get it right (60-80 should be OK for most documents).

 

Problem:

When I load a package in my R markdown document my rendered output contains all of the startup messages and/or warnings.

Solution:

You can load all of your packages at the start of your R markdown document in a code chunk along with setting your global options.

```{r, global_options, include=FALSE}
knitr::opts_chunk$set(message=FALSE, warning=FALSE, tidy.opts=list(width.cutoff=60)) 
suppressPackageStartupMessages(library(ggplot2))
```

The message=FALSE and warning=FALSE arguments suppress messages and warnings. The suppressPackageStartupMessages(library(ggplot2)) will load the ggplot2 package but suppress startup messages.

 

Problem:

When rendering my R markdown document to pdf my tables and/or figures are split over two pages.

Solution:

Add a page break using the LateX \pagebreak notation before your offending table or figure

 

Problem:

The code in my rendered document looks ugly!

Solution:

Add the argument tidy=TRUE to your global arguments. Sometimes, however, this can cause problems especially with correct code indentation.

```{r, global_options, include=FALSE}
knitr::opts_chunk$set(message=FALSE, tidy.opts=list(width.cutoff=60), tidy=TRUE) 
```