The YAML header of an .Rmd file

- There are many different components … to an RMarkdown document. … Let's take a detailed look at the YAML header, … which I've marked here as lines one through four. … The YAML header is at the very top of the document. … It needs to be the very first thing … in the .rmd file. … The header is delimited by three dashes … at both the beginning, and end. … Everything between these dashes is written in YAML. … So what's YAML? … YAML is an extremely popular language choice … for configuration files. … And that's kind of how we use it in our markdown. … YAML is very simple. … It's a set of key value pairs … with colons separating the option name, … and option value for your RMarkdown document. … It's not really necessary to learn YAML. … It's a thing that we use to set knitting options … in RMarkdown documents. … However, it's extremely useful to know … the header is written in YAML, … as it makes it much easier to google … exactly how do I modify X in my document. … Okay, now let's cover more explicitly …