Map/collect for transformation in Ruby - Mini Project: Build & Apply

Map/collect for transformation

📖 Scenario: You work at a small bakery. You have a list of prices for different pastries. You want to create a new list that shows the prices with tax added.

🎯 Goal: Build a Ruby program that uses map (also called collect) to add tax to each price in a list.

📋 What You'll Learn

Create an array called prices with the exact values: 2.5, 3.0, 4.75, 1.25

Create a variable called tax_rate and set it to 0.1 (which means 10% tax)

Use map on prices with block variable price to create a new array prices_with_tax where each price is increased by tax

Print the prices_with_tax array

💡 Why This Matters

🌍 Real World

Adding tax to prices is a common task in stores and online shops to show customers the final cost.

💼 Career

Understanding how to transform lists of data with <code>map</code> is a key skill for Ruby developers working with collections.

1

Create the initial prices array

Create an array called prices with these exact values: 2.5, 3.0, 4.75, 1.25

Ruby

# Create the prices array with the given values
# Your code here

Need a hint?

Use square brackets [] to create an array and separate values with commas.

2

Set the tax rate

Create a variable called tax_rate and set it to 0.1 (which means 10% tax)

Ruby

prices = [2.5, 3.0, 4.75, 1.25]
# Set the tax_rate variable to 0.1
# Your code here

Need a hint?

Just assign 0.1 to the variable tax_rate.

3

Use map to add tax to each price

Use map on the prices array with block variable price to create a new array called prices_with_tax. Each element should be the original price plus tax (price + price * tax_rate).

Ruby

prices = [2.5, 3.0, 4.75, 1.25]
tax_rate = 0.1
# Use map with block variable price to create prices_with_tax
# Your code here

Need a hint?

Use prices.map { |price| ... } and inside the block add tax to each price.

4

Print the prices with tax

Write a puts statement to print the prices_with_tax array.

Ruby

prices = [2.5, 3.0, 4.75, 1.25]
tax_rate = 0.1
prices_with_tax = prices.map { |price| price + price * tax_rate }
# Print the prices_with_tax array
# Your code here

Need a hint?

Use puts prices_with_tax to print each price on its own line.