Want to share your content on R-bloggers? click here if you have a blog, or here if you don't.
In his recent post 100 most read R posts for 2012 (stats from R-bloggers) – big data, visualization, data manipulation, and other languages Tal Galili – the guy behind R-Bloggers – presents his wishlist for 2013. Among other things he states
“The next step will be to have a “publish to your WordPress/blogger” button right from the RStudio console – allowing for the smoothest R blogging experience one could dream of.
I hope we’ll see this as early as possible in 2013.”
Given that I had some troubles myself recently with finding a convenient way of creating post for this blog (a blogspot site) and that I didn't want to wait until RStudio may integrate such functionality, I decided to come up with my own work around for the time being.
But let's start from the beginning:
What I want:
- I want to blog
- I want to blog using RStudio's R markdown framework (as it is very convenient)
- I want to have code highlighting in my posts
What I don't want:
- I don't want to manually fiddle around in the html code for each of the posts I create with RStudio
- I don't want write blog posts using the compose section on blogger
- Basically, I don't want to spend a lot of time on formatting (I rather spend the time on coding)
Why I want this:
- For starters, because I'm lazy
- Secondly, I want to integrate blogging into my teaching in the near future and for that I need a convenient and straight forward solution on how to create nice posts (after all I want to teach the students how to use R, not html)
The solution (as of now) is as follows (at least for me):
Yihui Xie has produced a SyntaxHighlighter Brush for the R Language which can be used for highlighting R code in blog posts.
In order to get the SyntaxHighlighter working on your blog, simply follow this tutorial at thebiobucket*.
However, the SyntaxHighlighter by Alex Gorbatchev, and subsequently also Yihui's brush for R, works a little different from the knitr code highlighting implementation. Basically, a chunk of code created with knitr is prepended by this little bit of html code:
<pre><code class="r">
whereas SyntaxHighlighter requires the following format for it to work:
<pre class="brush: r">
In order to automate the process of adjusting the brush definition needed for code highlighting using the SyntaxHighlighter brush I created the follwing function:
rmd2blogger <- function(rmdfile) {
stopifnot(require(knitr))
## knit rmdfile to <body> - only html
knit2html(rmdfile, fragment.only = TRUE)
## read knitted html file
htm.name <- gsub(".Rmd", ".html", rmdfile)
tmp <- readLines(htm.name)
## substitue important parts
tmp <- gsub("<pre><code class=\"r\">", "<pre class=\"brush: r\">", tmp)
tmp <- gsub("</code></pre>", "</pre>", tmp)
## write with .blg file ending
writeLines(tmp, paste(htm.name, ".blg", sep =""))
}
This function has two important components to it:
- it uses knitr's knit2html with fragment.only set to TRUE, which means your only creating the
<body>part of the html. - it produces a .html.blg file in the path where the .Rmd is located where all syntax highlighting brushes are formatted to work with Yihui's R brush
To use it, simply provide the path to the .Rmd file you want to publish on your blogspot.
rmd2blogger("someRmdFile.Rmd")
Now, you can simply open the .html.blg file in a text editor and copy the complete contents into the html editor for a new post on your blogger site and the code R should look like the one above.
In case you find any bugs, please let me know.
sessionInfo() ## R version 2.15.2 (2012-10-26) ## Platform: x86_64-pc-linux-gnu (64-bit) ## ## locale: ## [1] LC_CTYPE=en_US.UTF-8 LC_NUMERIC=C ## [3] LC_TIME=en_US.UTF-8 LC_COLLATE=en_US.UTF-8 ## [5] LC_MONETARY=en_US.UTF-8 LC_MESSAGES=en_US.UTF-8 ## [7] LC_PAPER=C LC_NAME=C ## [9] LC_ADDRESS=C LC_TELEPHONE=C ## [11] LC_MEASUREMENT=en_US.UTF-8 LC_IDENTIFICATION=C ## ## attached base packages: ## [1] parallel grid stats graphics grDevices utils datasets ## [8] methods base ## ## other attached packages: ## [1] rgdal_0.7-25 raster_1.9-92 gridBase_0.4-6 ## [4] latticeExtra_0.6-19 lattice_0.20-10 RColorBrewer_1.0-5 ## [7] sp_0.9-99 knitr_0.9 ## ## loaded via a namespace (and not attached): ## [1] digest_0.6.0 evaluate_0.4.3 formatR_0.7 markdown_0.5.3 ## [5] plyr_1.7.1 stringr_0.6 tools_2.15.2
R-bloggers.com offers daily e-mail updates about R news and tutorials about learning R and many other topics. Click here if you're looking to post or find an R/data-science job.
Want to share your content on R-bloggers? click here if you have a blog, or here if you don't.