Comparison operators in Python - Mini Project: Build & Apply

Comparison Operators in Python

📖 Scenario: You are helping a store manager check if products meet certain price conditions to decide discounts.

🎯 Goal: Build a small program that compares product prices to a threshold and shows if they are expensive or affordable.

📋 What You'll Learn

Create a dictionary with product names and their prices

Create a price threshold variable

Use comparison operators to check if each product price is greater than the threshold

Print the product name and whether it is 'Expensive' or 'Affordable'

💡 Why This Matters

🌍 Real World

Stores often need to compare prices to decide discounts or promotions.

💼 Career

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

1

Create the product prices dictionary

Create a dictionary called products with these exact entries: 'Laptop': 1200, 'Smartphone': 800, 'Tablet': 400, 'Headphones': 150

Python

# Create the products dictionary with prices
# Your code here

Hint

Use curly braces {} to create a dictionary with keys and values separated by colons.

2

Set the price threshold

Create a variable called price_threshold and set it to 500

Python

products = {'Laptop': 1200, 'Smartphone': 800, 'Tablet': 400, 'Headphones': 150}
# Create the price_threshold variable
# Your code here

Hint

Just assign the number 500 to the variable price_threshold.

3

Compare prices using comparison operators

Use a for loop with variables product and price to iterate over products.items(). Inside the loop, create a variable called status that is 'Expensive' if price > price_threshold, otherwise 'Affordable'

Python

products = {'Laptop': 1200, 'Smartphone': 800, 'Tablet': 400, 'Headphones': 150}
price_threshold = 500
# Use a for loop to check each product price
# Your code here

Hint

Use a for loop to go through each product and its price. Use an if-else expression to set status.

4

Print the product status

Inside the for loop, write a print statement that shows the product name and its status in this format: "Laptop is Expensive"

Python

products = {'Laptop': 1200, 'Smartphone': 800, 'Tablet': 400, 'Headphones': 150}
price_threshold = 500
for product, price in products.items():
    status = 'Expensive' if price > price_threshold else 'Affordable'
    # Print the product and status
    # Your code here

Hint

Use an f-string to combine product and status in the print statement.

Practice

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

easy

A. ==

B. =

C. !=

D. >

Solution

1. Step 1: Understand the equality operator

   The operator == is used to check if two values are equal in Python.

2. Step 2: Differentiate from assignment and other operators

   = is for assignment, != means not equal, and > means greater than.

3. Final Answer:

   == -> Option A

4. Quick Check:

   Equality check = == [OK]

Hint: Remember: double equals means equality check [OK]

Common Mistakes:

• Confusing = with ==
• Using != for equality
• Using > instead of ==

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

easy

A. x != 10

B. x <> 10

C. x =! 10

D. x !== 10

Solution

1. Step 1: Identify the correct not equal operator

   In Python, != is the correct operator for 'not equal'.

2. Step 2: Recognize invalid syntax

   <> is not valid in Python, =! and !== are syntax errors.

3. Final Answer:

   x != 10 -> Option A

4. Quick Check:

   Not equal operator = != [OK]

Hint: Use != for not equal, not <> or !== [OK]

Common Mistakes:

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

3. What will be the output of this code?

print(5 > 3 and 2 == 2)

medium

A. SyntaxError

B. False

C. True

D. None

Solution

1. Step 1: Evaluate each comparison

   5 > 3 is True, and 2 == 2 is True.

2. Step 2: Apply the 'and' operator

   True and True results in True.

3. Final Answer:

   True -> Option C

4. Quick Check:

   Both conditions True, so output True [OK]

Hint: Both sides must be True for 'and' to be True [OK]

Common Mistakes:

• Confusing 'and' with 'or'
• Misreading comparison results
• Expecting syntax error

4. Find the error in this code snippet:

if 4 =< 5:
    print("Yes")

medium

A. Missing colon after if statement

B. The operator =< is invalid in Python

C. Indentation error in print statement

D. Variable 4 cannot be compared

Solution

1. Step 1: Check the comparison operator

   The operator =< is not valid in Python; the correct operator is <=.

2. Step 2: Verify other syntax parts

   The colon is present and indentation is correct; 4 is a valid integer literal for comparison.

3. Final Answer:

   The operator =< is invalid in Python -> Option B

4. Quick Check:

   Use <= for less than or equal [OK]

Hint: Remember: less or equal is <=, not =< [OK]

Common Mistakes:

• Swapping operator symbols
• Missing colon
• Incorrect indentation

5. You want to check if a number n is between 10 and 20 inclusive. Which expression correctly uses comparison operators in Python?

hard

A. n > 10 or n < 20

B. 10 < n < 20

C. n >= 10 and n < 20

D. 10 <= n <= 20

Solution

1. Step 1: Understand inclusive range check

   Inclusive means n can be equal to 10 or 20, so use <= operators.

2. Step 2: Evaluate each option

   10 <= n <= 20 uses chained comparison which is correct and concise. 10 < n < 20 excludes 10 and 20. n >= 10 and n < 20 excludes 20. n > 10 or n < 20 uses 'or' which is incorrect for range check.

3. Final Answer:

   10 <= n <= 20 -> Option D

4. Quick Check:

   Use chained <= for inclusive range [OK]

Hint: Use chained comparisons for range checks [OK]

Common Mistakes:

• Using < instead of <=
• Using 'or' instead of 'and'
• Not including boundary values