Programmatically insert text, headers and lists with R markdown

Question

When using R markdown if one wants to add text using code there are some simple ways to do it.

This is also true for tables, using the kable command is very easy.

However, imagine you want to programmatically insert headers or lists to your report.

```{r, results='asis'} headers=list("We","are","your","friends") for (i in list_a){     #add i as header } ``` 

and you want this to be the same as writing in your Rmd file:

#We #are #your #friends 

Another example would be to automatically create headers instead of lists:

```{r, results='asis'} list_a=list("We","are","your","friends") for (i in list_a){     #print i to a rmd list } ``` 

as before this should have the same result as writing:

*We *are *your *friends 

This is not only a formatting problem as the table of context for Rmd files is created dynamically according to these headers.

Answer 1

You need to construct your wanted markdown in R and use that together with the argument results = 'asis' in your chunk options. Hence, something like the following will do what you want:

```{r, results='asis'} headers <- list("We","are","your","friends") for (i in headers){   cat("#", i, "\n") } ``` 

The for-loop here will create the output

# We  # are  # your  # friends  

which is used directly as input in the .md document.

Answer 2

Use the pander package, which transform R objects into Pandoc's markdown:

> headers=list("We","are","your","friends") > list_a=list("We","are","your","friends") > library(pander) > pandoc.header(headers)  # We  # are  # your  # friends > pander(list_a)     * We   * are   * your   * friends  <!-- end of list --> 

The first example used a helper function to create the headers, while the second demo simply called the generic S3 method, that can robustly transform a variety of R objects into markdown.