Variable scope (lexical scoping) in R Programming - Mini Project: Build & Apply

Variable scope (lexical scoping) in R

📖 Scenario: You are helping a friend understand how variables work inside and outside functions in R. This is important because sometimes variables inside a function can be different from those outside.

🎯 Goal: Build a small R script that shows how variable values change inside a function and how the outside variable stays the same. You will create a variable, write a function that uses a variable with the same name, and then print both to see the difference.

📋 What You'll Learn

Create a variable called number with the value 10

Write a function called change_number that creates a local variable number with value 5 and returns it

Call the function change_number and save its result in a variable called new_number

Print both number and new_number to show their values

💡 Why This Matters

🌍 Real World

Understanding variable scope helps avoid bugs when writing functions that use variables with the same names as outside variables.

💼 Career

Many programming jobs require writing clean functions that do not accidentally change important data outside their scope.

1

Create the initial variable

Create a variable called number and set it to 10.

R Programming

# Create a variable called number and set it to 10
# Your code here

Need a hint?

Use the assignment operator <- to set the value.

2

Write a function with a local variable

Write a function called change_number that creates a local variable number with value 5 and returns number.

R Programming

number <- 10
# Write the function change_number below
# Your code here

Need a hint?

Inside the function, create a variable number and use return() to send it back.

3

Call the function and save the result

Call the function change_number and save its result in a variable called new_number.

R Programming

number <- 10
change_number <- function() {
  number <- 5
  return(number)
}
# Call change_number and save the result in new_number
# Your code here

Need a hint?

Use the function name with parentheses to call it and assign the result.

4

Print both variables to see the difference

Print the variables number and new_number using two separate print() statements.

R Programming

number <- 10
change_number <- function() {
  number <- 5
  return(number)
}
new_number <- change_number()
# Print number and new_number
# Your code here

Need a hint?

Use print(number) and print(new_number) to show their values.