Method chaining patterns in Ruby - Mini Project: Build & Apply

Method chaining patterns

📖 Scenario: Imagine you are working with a list of book titles in a library system. You want to process these titles by cleaning up the text and then selecting only the titles that meet certain conditions.

🎯 Goal: You will build a Ruby program that uses method chaining to clean and filter a list of book titles step-by-step.

📋 What You'll Learn

Create an array of book titles with exact values

Create a variable for the minimum length of titles to keep

Use method chaining to clean and filter the titles

Print the final filtered list of titles

💡 Why This Matters

🌍 Real World

Cleaning and filtering lists of text data is common in apps like library catalogs, contact lists, or product inventories.

💼 Career

Understanding method chaining helps you write clean, readable code for data processing tasks in Ruby development jobs.

1

Create the initial array of book titles

Create an array called book_titles with these exact strings: " The Hobbit ", "War and Peace", "1984", " Brave New World ", and "Ulysses".

Ruby

# Create the array book_titles with the exact titles
# Your code here

Need a hint?

Use square brackets [] to create an array and include the exact strings with quotes.

2

Set the minimum title length

Create a variable called min_length and set it to 10.

Ruby

book_titles = ["  The Hobbit  ", "War and Peace", "1984", " Brave New World ", "Ulysses"]
# Create min_length variable and set it to 10
# Your code here

Need a hint?

Just assign the number 10 to the variable min_length.

3

Use method chaining to clean and filter titles

Create a new variable called filtered_titles that uses method chaining on book_titles to first remove extra spaces from each title using map(&:strip), then select only titles with length greater than or equal to min_length using select.

Ruby

book_titles = ["  The Hobbit  ", "War and Peace", "1984", " Brave New World ", "Ulysses"]
min_length = 10
# Use method chaining to strip spaces and filter by min_length
# Your code here

Need a hint?

Use map(&:strip) to remove spaces, then select with a block to keep titles with length >= min_length.

4

Print the filtered titles

Write a puts statement to print the filtered_titles array.

Ruby

book_titles = ["  The Hobbit  ", "War and Peace", "1984", " Brave New World ", "Ulysses"]
min_length = 10
filtered_titles = book_titles.map(&:strip).select { |title| title.length >= min_length }
# Print the filtered_titles array
# Your code here

Need a hint?

Use puts filtered_titles to print each title on its own line.