As you know by now, R is all about functions. In the event that there isn’t one for the exact thing you want to do, you can even write your own! Writing your own functions is a very useful way to automate your work. Once defined, it’s easy to call new functions as often as you need. It’s a good habit to get into when programming with R — and with lots of other languages as well.
Defining a function uses another function simply called function(). Function names follow pretty much the same rules as variable names, so you can call them anything that would also be acceptable as a variable name.