The "..." or ellipsis argument to a function allows the function to accept unnamed and unspecified arguments to pass along to other functions called by the original function. Such an argument is common in R functions and is perhaps most familiar in graphical functions that allow unspecified graphical parameters in addition to the arguments specifically programmed into the function and described on the function's help page. In this video we illustrate the use of the ellipsis argument via a detection limit substitution function that takes a vector of data, substitutes a value for any below-detection limit observations and then, optionally, plots the data with a dot plot (aka strip chart). Unnamed arguments are accepted and passed along to the plotting function to allow the user to, optionally, add a title, change graphical parameters, or modify the default options of the stripchart() function.

You should follow along with Example 11 when watching this video, which is essential content for the course.

Example 12 from Mod11Script.R is not featured in this video and indeed does not involve the ellipsis argument, but be sure to read through that example too to see a function that plays "Rock, Paper, Scissors".