Ruby Interview Questions

Top 15 Ruby Interview Questions

Are you searching for important Ruby interview questions? The team at GoApti has prepared a list of 15 questions you may be quizzed on for your Ruby interview.

Ruby is an interpreted, high-level, general-purpose programming language. It was designed and developed in the mid-1990s by Yukihiro “Matz” Matsumoto in Japan. Ruby is dynamically typed and uses garbage collection. It supports multiple programming paradigms, including procedural, object-oriented, and functional programming. According to the creator, Ruby was influenced by Perl, Smalltalk, Eiffel, Ada, Basic, and Lisp. Source: Wikipedia

1. What is Ruby?

Ruby is a dynamic, reflective, general-purpose, open-source programming language that focuses on simplicity and productivity. Ruby is a pure object-oriented programming language.

2. What are some of the features of Ruby Programming Language?

Some prominent features of Ruby are:

  • Ruby is an open-source programming language.
  • Ruby is a general-purpose and interpreted programming language.
  • Ruby is an object-oriented language.
  • Ruby is a server-side scripting language and shares similarities with Python and PERL.
  • Ruby can be used to write Common Gateway Interface (CGI) scripts.
  • Ruby can be embedded in Hypertext Markup Language (HTML).
  • Ruby has a clean and easy syntax that allows new developers to learn it quickly without much trouble.
  • Ruby has a syntax that resembles other programming languages like C++ and Perl.
  • Programs written in Ruby are easy to scale and maintain.
  • Ruby has a rich set of built-in functions, which can be used directly into Ruby scripts.

3. Which editors can be used for writing Ruby code?

These are some of the Linux and Window-based editors for writing Ruby code:

  • You can use Notepad or Edit plus on Windows.
  • You can use VIM on Linux
  • RubyWin is a Ruby Integrated Development Environment (IDE) for Windows.

4. What are the different variables in Ruby?

Ruby has four types of variables:

  1. Local Variables: Local variables are the variables defined in a method. Local variables are not available outside the method.
  2. Instance Variables: Instance variables are available across methods for any particular instance or object. It means the value of an instance variable may change from object to object.
  3. Class Variables: Class variables are available across different objects. A class variable belongs to the class and is a characteristic of the class.
  4. Global Variables: If you want to have a single variable that is available across classes, you need to define a global variable.

5. What command retrieves the Ruby version installed on your system?

The command to fetch the installed Ruby version is:
Ruby –v

Must Read: Top 10 Effective Maven Interview Questions

6. What are the different types of operators available in Ruby?

The different operators in Ruby are:

  • Unary operator.
  • Arithmetic operator.
  • Bitwise operator.
  • Logical operator.
  • Ternary operator.

7. What are the different class libraries in Ruby?

The different class libraries in Ruby are:

  • Text processing.
  • CGI Programming.
  • Network programming.
  • GUI programming.
  • XML programming.

8. What are the different data types in Ruby?

The different data types in Ruby are:

  • Numbers.
  • Strings.
  • Symbols.
  • Hashes
  • Arrays.
  • Boolean.

Click here for the official website of Ruby

9. What are the different iterators in Ruby?

The different iterators in Ruby are:

  • Each iterator.
  • Times iterator.
  • Up to and down to iterator.
  • Step iterator.
  • Each_line iterator.

10. What is the use of Super?

Super is used to call the parent class’s initialize method from the child class’s initialize method.

This awesome article explains more about super in Ruby.

11. How do you declare a block in Ruby?

In Ruby, a code block is created using within braces, i.e., {}. You can invoke a block by using the yield statement.

12. What are the levels of method access control for classes in Ruby?

There are three levels of method access control for classes:

  • Public Methods: These methods can be called by the objects and sub-classes of the class in which they are defined.
  • Protected Methods: Protected methods are only accessible to objects within the same class.
  • Private Methods: These methods can only be called within the class they belong to.

13. How does a symbol differ from a string?

  1. Multiple symbols representing a single value are identical, whereas this is not possible with the Strings.
  2. Symbols can be thought of as faster, immutable strings.
  3. Once a string is used up, it is marked for cleaning by the garbage collector but it is not cleaned up immediately and cannot be reused. Symbols live for the duration of the session and it can be reused. However, symbols can lead to increased memory usage.

14. What is interpolation in Ruby Programming Language?

Interpolation is an important process in Ruby. Interpolation is the process of inserting a string into a literal. There is only one way in which you can interpolate a string into a literal: by placing a hash, i.e., “#”, within the braces {}. Interpolation refers to a copy of the original method.

15. What is the difference between NIL and FALSE in Ruby?

The differences between NIL and FALSE in Ruby are:

  1. FALSE is a boolean data type, whereas NIL is not.
  2. NIL cannot be a value, whereas a FALSE can be a value.
  3. A method returns true or FALSE in case of a predicate, otherwise, it returns NIL.
  4. NIL is an object of the NilClass, whereas FALSE is an object of the FalseClass

Have you appeared for an interview based on the Ruby programming language? Are there are any must-know concepts or questions candidates must be aware of? We’d love to hear from you in the comments section.

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