Comparison operators in R Programming - Mini Project: Build & Apply

Comparison Operators in R

📖 Scenario: You are working in a small shop and want to check which products are priced above a certain amount to decide which ones to promote.

🎯 Goal: Build a simple R program that uses comparison operators to find products priced above a threshold.

📋 What You'll Learn

Create a named numeric vector called products with exact product names and prices

Create a numeric variable called threshold with the value 50

Use a comparison operator to create a logical vector called expensive_products that is TRUE for products priced above threshold

Print the expensive_products vector

💡 Why This Matters

🌍 Real World

Shops often need to filter products by price to decide which items to promote or discount.

💼 Career

Understanding comparison operators is essential for data filtering and decision making in data analysis and programming jobs.

1

Create the products vector

Create a named numeric vector called products with these exact entries: apple = 30, banana = 20, cherry = 60, date = 80, elderberry = 40.

R Programming

# Create the products vector with exact names and prices
# Your code here

Hint

Use the c() function with named elements like name = value.

2

Set the price threshold

Create a numeric variable called threshold and set it to 50.

R Programming

products <- c(apple = 30, banana = 20, cherry = 60, date = 80, elderberry = 40)
# Create the threshold variable and set it to 50
# Your code here

Hint

Just assign the number 50 to the variable threshold.

3

Find products priced above the threshold

Use the greater than operator > to create a logical vector called expensive_products that is TRUE for products priced above threshold.

R Programming

products  with threshold
# Your code here

Hint

Use products > threshold to get TRUE or FALSE for each product.

4

Print the result

Print the expensive_products vector to see which products are above the threshold.

R Programming

products  threshold
# Print expensive_products
# Your code here

Hint

Use print(expensive_products) to show the logical vector.

Practice

1. Which of the following comparison operators in R checks if two values are equal?

easy

A. !=

B. =

C. <>

D. ==

Solution

1. Step 1: Understand equality operator in R

   In R, the operator to check if two values are equal is ==.

2. Step 2: Differentiate from other operators

   = is for assignment, != means not equal, and <> is not valid in R.

3. Final Answer:

   == -> Option D

4. Quick Check:

   Equality operator = == [OK]

Hint: Use double equals (==) to test equality in R [OK]

Common Mistakes:

• Using single = instead of ==
• Confusing != with equality
• Using <> which is invalid in R

2. Which of the following is the correct syntax to check if variable x is NOT equal to 10 in R?

easy

A. x != 10

B. x <> 10

C. x =! 10

D. x !== 10

Solution

1. Step 1: Identify the not equal operator in R

   R uses != to check if two values are not equal.

2. Step 2: Check syntax correctness

   <> and !== are not valid in R, and =! is incorrect syntax.

3. Final Answer:

   x != 10 -> Option A

4. Quick Check:

   Not equal operator = != [OK]

Hint: Use != to check inequality in R [OK]

Common Mistakes:

• Using <> which is invalid in R
• Writing =! instead of !=
• Using !== which is from other languages

3. What is the output of the following R code?

x <- 5
y <- 7
x > y

medium

A. FALSE

B. TRUE

C. 5

D. Error

Solution

1. Step 1: Compare values of x and y

   x is 5 and y is 7, so 5 > 7 is being checked.

2. Step 2: Evaluate the comparison

   Since 5 is not greater than 7, the expression returns FALSE.

3. Final Answer:

   FALSE -> Option A

4. Quick Check:

   5 > 7 = FALSE [OK]

Hint: Compare numbers directly; 5 > 7 is false [OK]

Common Mistakes:

• Confusing > with <
• Expecting numeric output instead of logical
• Thinking it causes an error

4. Identify the error in this R code snippet:

if (x = 10) { print("Yes") }

medium

A. No error, code is correct

B. Missing curly braces

C. Using = instead of ==

D. print() is incorrect function

Solution

1. Step 1: Check the condition syntax in if statement

   In R, to compare values, use ==, not =.

2. Step 2: Understand the difference between assignment and comparison

   = assigns a value, but == tests equality. Using = in if condition causes an error or unexpected behavior.

3. Final Answer:

   Using = instead of == -> Option C

4. Quick Check:

   Comparison needs ==, not = [OK]

Hint: Use == for comparison inside if() [OK]

Common Mistakes:

• Using = instead of ==
• Ignoring syntax errors from wrong operator
• Thinking = works for comparison

5. You want to filter a vector v <- c(3, 5, 7, 9) to keep only values greater than or equal to 5. Which R expression correctly uses comparison operators to do this?

hard

A. v[v => 5]

B. v[v >= 5]

C. v[v = 5]

D. v[v >== 5]

Solution

1. Step 1: Understand filtering with comparison

   To keep values >= 5, use the operator >= inside the indexing brackets.

2. Step 2: Check syntax correctness

   =>, =, and >== are invalid operators in R.

3. Final Answer:

   v[v >= 5] -> Option B

4. Quick Check:

   Use >= for greater or equal in filtering [OK]

Hint: Use >= for greater or equal comparisons [OK]

Common Mistakes:

• Using => which is invalid
• Using = instead of comparison operator
• Combining > and == incorrectly