100 Must-Know Ruby Interview Questions and Answers 2024

Ruby Fundamentals

1.
What is Ruby, and why is it popular for web development?
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2.
How do you create a Ruby script file and execute it on a command line?
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3.
What are the basic data types in Ruby?
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4.
Explain the difference between symbols and strings in Ruby.
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5.
How are constants declared and what is their scope in Ruby?
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6.
Explain the use of ‘require’ and ‘include’ in Ruby.
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7.
What are Ruby iterators and how do they work?
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8.
How are errors handled in Ruby?
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9.
Describe the difference between local, instance, and class variables.
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10.
What are Ruby’s accessor methods?
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11.
How does garbage collection work in Ruby?
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12.
Explain the difference between ‘gets.chomp’ and ‘gets.strip’.
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13.
What is the role of ‘self’ in Ruby?
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14.
Explain the principle of ‘Convention over Configuration’ in the context of Ruby.
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15.
How does Ruby support metaprogramming?
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Object-Oriented Programming in Ruby

16.
Define classes and modules in Ruby.
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17.
How does inheritance work in Ruby?
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18.
What is method overriding in Ruby?
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19.
Explain the use of ‘super’ in Ruby’s classes.
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20.
What are mixins and how do they differ from inheritance?
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21.
What is a singleton method?
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22.
Explain how to create a class-level method.
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23.
What are virtual methods in Ruby?
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24.
How do you prevent an object from being instantiated in Ruby?
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25.
Explain the concept of an object’s eigenclass in Ruby.
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Ruby Data Structures

26.
How do you work with arrays in Ruby?
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27.
Describe various methods to manipulate strings in Ruby.
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28.
Explain how hashes work in Ruby.
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29.
How do ranges function in Ruby?
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30.
What is the purpose of Enumerable methods?
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31.
How do you implement a linked list in Ruby?
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32.
Discuss ways to search for data in an array or hash.
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33.
How can you sort arrays and hashes?
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Control Structures and Loops

34.
Describe how to use ‘if-else’ control structures in Ruby.
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35.
What are Ruby’s loop constructs and how do they work?
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36.
Explain the difference between ‘for loops’ and ‘each iterators’.
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37.
How does ‘next’ differ from ‘break’ in a loop?
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Blocks, Procs, and Lambdas

38.
What is a block in Ruby?
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39.
Explain the difference between a block, a Proc, and a lambda.
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40.
How do you pass a block to a method?
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41.
How can you convert a block to a Proc?
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42.
Explain arity in the context of Procs and lambdas.
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Ruby Gems and Libraries

43.
What is a Ruby Gem and how do you use it?
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44.
Explain the purpose of RubyGems.org.
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45.
How do you create your own Ruby Gem?
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46.
What is Bundler and how does it work?
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47.
Describe the process of managing dependencies with Bundler.
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Ruby on Rails

48.
Describe MVC architecture as it relates to Ruby on Rails.
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49.
Explain how to create a new Rails application.
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50.
What is ActiveRecord and how does it work?
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51.
What is the asset pipeline in Rails?
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52.
How do you handle routes in Rails?
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53.
What are Rails migrations?
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54.
How would you implement authentication in a Rails app?
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55.
Explain what a “concern” is in Ruby on Rails.
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56.
How do you perform file uploads in Rails?
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57.
What are filters in Rails controllers?
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Testing in Ruby

58.
How do you write tests in Ruby with Minitest or RSpec?
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59.
Explain Behavior-Driven Development (BDD) with Ruby.
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60.
What is Test-Driven Development (TDD) and how do you apply it in Ruby?
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61.
What is a Mock, and how is it used in testing?
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62.
Describe the difference between unit tests and integration tests.
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Ruby Best Practices

63.
How do you optimize Ruby code for better performance?
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64.
What are some best practices for writing clean and maintainable Ruby code?
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65.
How do you manage different versions of Ruby on the same system?
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66.
What is pair programming and how does it fit with Ruby development?
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Advanced Ruby Concepts

67.
Explain how concurrency works in Ruby.
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68.
What is the Global Interpreter Lock (GIL) in Ruby?
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69.
How do threads work in Ruby, and when should you use them?
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70.
What is event-driven programming and how can you achieve it in Ruby?
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71.
Describe how to implement a DSL (Domain-Specific Language) in Ruby.
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72.
Explain Ruby’s memory model and how it impacts performance.
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73.
How does Ruby handle monkey patching and what are its potential pitfalls?
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Ruby in the Web Context

74.
How does Ruby interact with web frameworks like Rails or Sinatra?
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75.
What is Rack in the context of Ruby web development?
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76.
Describe the role of WebSockets in a Ruby application.
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77.
How do you process form data in Ruby?
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78.
Explain Model-View-Controller (MVC) and how Ruby fits into this pattern.
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Metaprogramming with Ruby

79.
What is reflection in Ruby and how do you use it?
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80.
How does Ruby handle dynamic method invocation?
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81.
Describe how to use method_missing for handling undefined methods.
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82.
Explain the use of OpenStruct as opposed to a Hash.
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83.
What are metaclasses in Ruby?
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Concurrency and Parallelism

84.
How is the ‘fork’ operation used in Ruby?
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85.
Explain the difference between concurrency and parallelism.
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86.
What are mutexes and how do they work in Ruby?
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87.
Discuss Ruby’s support for asynchronous IO.
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Networking with Ruby

88.
How do you open and read from sockets in Ruby?
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89.
How does Ruby support HTTP operations?
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90.
Describe how to create a simple server using Ruby.
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File System and I/O

91.
How do you perform file I/O operations in Ruby?
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92.
What are the different modes of File I/O in Ruby?
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93.
How do you navigate through directories and process files in Ruby?
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Ruby on the System Level

94.
How do you execute system commands from Ruby scripts?
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95.
What are Ruby’s capabilities for systems administration tasks?
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96.
Explain the use of environment variables in Ruby.
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97.
Describe Ruby’s support for Unicode and character encoding.
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Ruby and Databases

98.
How do you establish a connection with a relational database in Ruby?
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99.
Explain ORM in the context of Ruby.
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100.
What are DB migrations, and how would you manage them in a Ruby context?
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100 Ruby interview questions

What is Ruby, and why is it popular for web development?

How do you create a Ruby script file and execute it on a command line?

What are the basic data types in Ruby?

Explain the difference between symbols and strings in Ruby.

How are constants declared and what is their scope in Ruby?

Explain the use of ‘require’ and ‘include’ in Ruby.

What are Ruby iterators and how do they work?

How are errors handled in Ruby?

Describe the difference between local, instance, and class variables.

What are Ruby’s accessor methods?

How does garbage collection work in Ruby?

Explain the difference between ‘gets.chomp’ and ‘gets.strip’.

What is the role of ‘self’ in Ruby?

Explain the principle of ‘Convention over Configuration’ in the context of Ruby.

How does Ruby support metaprogramming?

Define classes and modules in Ruby.

How does inheritance work in Ruby?

What is method overriding in Ruby?

Explain the use of ‘super’ in Ruby’s classes.

What are mixins and how do they differ from inheritance?

What is a singleton method?

Explain how to create a class-level method.

What are virtual methods in Ruby?

How do you prevent an object from being instantiated in Ruby?

Explain the concept of an object’s eigenclass in Ruby.

How do you work with arrays in Ruby?

Describe various methods to manipulate strings in Ruby.

Explain how hashes work in Ruby.

How do ranges function in Ruby?

What is the purpose of Enumerable methods?

How do you implement a linked list in Ruby?

Discuss ways to search for data in an array or hash.

How can you sort arrays and hashes?

Describe how to use ‘if-else’ control structures in Ruby.

What are Ruby’s loop constructs and how do they work?

Explain the difference between ‘for loops’ and ‘each iterators’.

How does ‘next’ differ from ‘break’ in a loop?

What is a block in Ruby?

Explain the difference between a block, a Proc, and a lambda.

How do you pass a block to a method?

How can you convert a block to a Proc?

Explain arity in the context of Procs and lambdas.

What is a Ruby Gem and how do you use it?

Explain the purpose of RubyGems.org.

How do you create your own Ruby Gem?

What is Bundler and how does it work?

Describe the process of managing dependencies with Bundler.

Describe MVC architecture as it relates to Ruby on Rails.

Explain how to create a new Rails application.

What is ActiveRecord and how does it work?

What is the asset pipeline in Rails?

How do you handle routes in Rails?

What are Rails migrations?

How would you implement authentication in a Rails app?

Explain what a “concern” is in Ruby on Rails.

How do you perform file uploads in Rails?

What are filters in Rails controllers?

How do you write tests in Ruby with Minitest or RSpec?

Explain Behavior-Driven Development (BDD) with Ruby.

What is Test-Driven Development (TDD) and how do you apply it in Ruby?

What is a Mock, and how is it used in testing?

Describe the difference between unit tests and integration tests.

How do you optimize Ruby code for better performance?

What are some best practices for writing clean and maintainable Ruby code?

How do you manage different versions of Ruby on the same system?

What is pair programming and how does it fit with Ruby development?

Explain how concurrency works in Ruby.

What is the Global Interpreter Lock (GIL) in Ruby?

How do threads work in Ruby, and when should you use them?

What is event-driven programming and how can you achieve it in Ruby?

Describe how to implement a DSL (Domain-Specific Language) in Ruby.

Explain Ruby’s memory model and how it impacts performance.

How does Ruby handle monkey patching and what are its potential pitfalls?

How does Ruby interact with web frameworks like Rails or Sinatra?

What is Rack in the context of Ruby web development?

Describe the role of WebSockets in a Ruby application.

How do you process form data in Ruby?