Theme_preview.Rmd

---
title: "R Notebook"
output:
  html_document:
    df_print: paged
---

# This is a preview of the theme

Lorem ipsum **dolor sit amet**, consectetur adipiscing elit, sed do eiusmod tempor 
incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud
exercitation ullamco laboris _nisi ut aliquip_ ex ea commodo consequat. 

Duis aute irure dolor in reprehenderit in `voluptate velit esse` cillum dolore eu 
fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa 
qui officia deserunt mollit [anim id est](http://www.test.com) laborum. 

<http://www.google.com>

    
   > An inline block-quote.

```{r folded_block}
# This block should be folded for the screenshot.
```


```{r blockname, echo=TRUE, eval=FALSE}
#' Mirror the rows/cols of a matrix
#'
#' @param mat (Matrix) A matrix.
#' @param MARGIN (Integer) `1` to reverse order of cols, `2` to reverse rows.
#'
#' @return A mirrored matrix.
#' @export
#'
#' @md
mirror_matrix <- function(mat, MARGIN = 2) {
    # Here's an inline comment.
    new_order <- dim(mat)[MARGIN]:1 
    
    if (MARGIN == 1 | MARGIN == TRUE) {
        mat[new_order, ]
    } else if (MARGIN == 2) {
        mat[, new_order]
    } else {
        stop("Argument 'MARGIN' must be set to either '1' (rows) or '2' (cols).")
    }
}
```