Explain what an R function is; describe what an argument to an R function is

An R function is a piece of code that you can run multiple times. It allows you to automate parts of your code that are repeatable. It is a block of code that can perform a specific task and can be executed whenever needed in the program. Functions are the fundamental building blocks of R: if you master functions in R, you'll make your data analysis more efficient and reliable.

An argument to an R function is a value that is passed into the function when it is called. These arguments can be used within the function to perform certain tasks. For example, in the function sum(x, y), x and y are arguments. When you call sum(2, 3), 2 and 3 are the argument values that are passed to the function. The function then adds these values together and returns the result.

In R, arguments can be mandatory or optional. Mandatory arguments are those that must be included in the function call while optional arguments have default values that are used if the argument is not specified in the function call.