Introduction to Writing Functions in R

Functions in R allow you to write reusable blocks of code, making your programs more efficient and organized.

Defining a Function

Use the function keyword to define a function.

my_function <- function() {
  print('Hello, R!')
}
my_function()

Function Arguments

Functions can accept arguments to make them more flexible.

add_numbers <- function(a, b) {
  return(a + b)
}
add_numbers(3, 5)

Default Arguments

You can assign default values to function arguments.

multiply <- function(a, b = 2) {
  return(a * b)
}
multiply(5)

Returning Values

Functions return values using the return() statement.

square <- function(x) {
  return(x^2)
}
square(4)

Using Functions Inside Functions

Functions can call other functions for better modularity.

power <- function(x, y) {
  return(x^y)
}
calculate <- function(a) {
  return(power(a, 3))
}
calculate(2)

Anonymous Functions

Anonymous functions can be created using function() without a name.

(function(x) x + 2)(5)

Applying Functions to Vectors

You can apply functions to vectors using sapply() or lapply().

numbers <- c(1, 2, 3, 4)
sapply(numbers, square)

Summary

In this lesson, you learned:

• How to create and use functions in R.
• How to pass arguments and return values.
• How to use functions inside other functions.