Useful Array and Hash Methods
Discover powerful methods like compact, flatten, merge, sort, and keys.
Useful Array and Hash Methods is a free Ruby Academy lesson on CoddyKit. This is lesson 3 of 3. Any 3 lessons of this learning path are free to read in full — after that, CoddyKit PRO unlocks every lesson, plus hands-on practice with a built-in code editor and a 24/7 AI tutor. It is part of the Ruby Academy learning path, and your progress syncs across the web and the CoddyKit app. The Ruby Academy course includes 3 lessons in total.
Overview of Array and Hash Methods
Useful Array and Hash Methods
Ruby provides many useful methods to work with Arrays and Hashes efficiently.
In this lesson, you will explore methods like compact, flatten, merge, sort, and keys.
Using Compact
The compact method removes nil values from an array.
numbers = [1, nil, 2, nil, 3]
puts numbers.compactUsing Flatten
The flatten method converts nested arrays into a single array.
nested_array = [[1, 2], [3, 4], [5, 6]]
puts nested_array.flattenUsing Merge
The merge method combines two hashes.
hash1 = {a: 1, b: 2}
hash2 = {b: 3, c: 4}
puts hash1.merge(hash2)Using Sort
The sort method arranges elements in ascending order.
numbers = [5, 3, 8, 1, 2]
puts numbers.sortUsing Reverse
The reverse method reverses the order of elements in an array.
numbers = [1, 2, 3, 4, 5]
puts numbers.reverseUsing Keys
The keys method returns all keys from a hash.
person = {name: 'Alice', age: 25, city: 'New York'}
puts person.keysUsing Values
The values method returns all values from a hash.
person = {name: 'Alice', age: 25, city: 'New York'}
puts person.valuesCongratulations!
You have learned useful array and hash methods in Ruby.
Next, you will explore object-oriented programming concepts in Ruby.
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Frequently Asked Questions
Is the “Useful Array and Hash Methods” lesson free?
Yes — any 3 lessons of the Ruby Academy learning path, including “Useful Array and Hash Methods”, are free to read in full here on the web. After that, CoddyKit PRO unlocks every lesson, plus interactive practice with a built-in code editor and a 24/7 AI tutor. The Ruby Academy course includes 3 lessons in total.
What will I learn in “Useful Array and Hash Methods”?
Discover powerful methods like compact, flatten, merge, sort, and keys. You practise Ruby Academy with hands-on code you run directly in the browser, and a 24/7 AI tutor answers your questions as you work through the lesson.
Do I need any experience to start Ruby Academy?
No prior experience is required. Ruby Academy on CoddyKit is structured for beginners through advanced learners, so you can start here or from the beginning and move at your own pace. This is lesson 3 of 3.
How long does the “Useful Array and Hash Methods” lesson take?
Most CoddyKit lessons take about 5–10 minutes. Each one is bite-sized and interactive, so you make steady progress and pick up exactly where you left off across the web and the app.
Can I write and run code in this Ruby Academy lesson?
Yes. Every Ruby Academy lesson includes a built-in code editor, so you write and run real code right in your browser and get instant AI feedback — no local setup required.
All lessons in this course
- Arrays and Hashes
- Iterating Over Collections
- Useful Array and Hash Methods