Function arguments in R Programming - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is a function argument in R?

A function argument is a value you give to a function when you call it. It tells the function what data to work with.

beginner

How do you define a function with arguments in R?

You write the function name, then inside parentheses list the argument names. For example: myfun <- function(x, y) { x + y } defines a function with two arguments, x and y.

intermediate

What happens if you call a function without providing all its arguments?

If the function has default values for some arguments, those defaults are used. Otherwise, R will give an error saying an argument is missing.

intermediate

What is a default argument value in R functions?

A default argument value is a value assigned to an argument in the function definition. If you don’t provide that argument when calling the function, R uses the default.

beginner

How can you pass arguments to a function by name in R?

You can specify the argument name when calling the function, like myfun(y = 5, x = 3). This lets you give arguments in any order.

What will happen if you call sum(1, 2) in R?

A It returns 2

B It returns 3

C It returns 1

D It returns an error

The sum function adds the numbers 1 and 2 and returns 3.

How do you set a default value for an argument in an R function?

A By assigning a value in the function definition, like <code>function(x = 5)</code>

B By calling the function with no arguments

C By using the <code>default()</code> function

D By writing <code>setdefault(x)</code>

You assign a default value directly in the function definition.

What is the correct way to call a function with named arguments in R?

A <code>myfun(x = 2, y = 3)</code>

B <code>myfun(2, 3)</code>

C <code>myfun(, x = 2, y = 3)</code>

D <code>myfun(x:2, y:3)</code>

Named arguments use the syntax name = value inside the function call.

If a function argument has a default value, what happens when you omit it in the call?

A An error occurs

B The function ignores the argument

C The argument becomes NULL

D The default value is used

R uses the default value if you don’t provide that argument.

Which of these is NOT a valid way to pass arguments to a function in R?

A By position, like <code>fun(1, 2)</code>

B By name, like <code>fun(y = 2, x = 1)</code>

C By using <code>fun(x:1, y:2)</code>

D By mixing named and positional arguments

The syntax x:1 is not valid for passing arguments in R.

Explain how function arguments work in R and how default values affect function calls.

Think about what happens when you call a function with fewer arguments than defined.

Describe how to use named arguments in R function calls and why they might be helpful.

Consider how naming arguments can make your code easier to read and less error-prone.