Introduction to Ruby Interview Questions And Answers
Ruby is an open source programming language, object-oriented language with a focus on simplicity, portability, extensibility, and productivity. It was developed mostly on Linux and works across all platforms like UNIX, Windows, DOS, and Mac OS etc. Due to its simple syntax, makes it easy to read and write if we are familiar with other programming languages like python. Ruby was created by Yukihiro Matsumoto and first released in 1995. As it is open source, we can free to modify, edit according to our needs and use. Ruby is similar to Smalltalk and Perl as it is object-oriented like Smalltalk and convenient as Perl which makes it programs to easier to maintain. As Ruby is one of the demanding programming languages in the market, cracking its interview needs skill.
Now, if you are looking for a job which is related to Ruby then you need to prepare for the Ruby Interview Questions. It is true that every interview is different as per the different job profiles but still to clear the interview you need to have a good and clear knowledge of Ruby. Here, we have prepared the important Ruby Interview Questions and Answers which will help you get success in your interview.
Below are the 10 important Ruby Interview Questions and Answers that are frequently asked in an interview. these questions are divided into parts are as follows:
Part 1 – Ruby Interview Questions (Basic)
This first part covers basic Ruby Interview Questions and Answers
1. What is the difference between raise/rescue and throw/catch in ruby?
Raise and rescue are used to raise and handle exceptions which are often used for exception handling whereas throw and catch accept only matching symbols as arguments and considered as a control-flow structure and not used for exception handling in common. Raise and Rescue is the fundamental part of the Ruby language.
2. What are Ruby variables and explain each?
There are four types of variables in Ruby as below:
- Global Variables: These variables start with $ and its scope is available for entire Ruby program.
- Class variables: These variables start with @@ and accessible by all instances of the class that is defined in.
- Local variable: These variables start with lower case letter or an underscore and scope are within the function or code construct where it is declared.
- Instance variable: These variables start with @ and similar to class variables except class variables are local to a single instance of a class.
Let us move to the next Ruby Interview Questions And Answer.
3. What are the advantages of using Ruby?
Ruby is pure object-oriented language as everything in it is an object like methods, classes etc which provides a lot of possibilities while developing.
- Ruby is open-source language, 100 percent free with the large developer community.
- Ruby is well-suited for Metaprogramming, it provides an ability to write code that depends on other code.
- Ruby has simple and easy syntax; users can develop complex programs within in few lines of code. The code is human readable and easy to follow and understand.
4. What is the difference between statement and expression in Ruby?
In Ruby, all statements are expressions as every statement will return a value. A statement is a simple way to refer for any syntax. This is the basic Ruby Interview Questions which is asked in an interview.
5. Why use “each” instead of “For/in” Ruby?
It all depends on ruby moreover it is a ruby’s way. It shows how ruby defines methods that mimic/ exact copy of natural language concepts. #each is an iterator method which reads more naturally and it is a block which defines new variable scope whereas #for/it depends on the existence of #each which means #each is a fundamental part of natural language. So in ruby #each is used instead of #for/in.
Part 2 –Ruby Interview Questions (Advanced)
Let us now have a look at the advanced Ruby Interview Questions.
6. Describe method name resolution process in Ruby?
Below are the steps to follow for method name resolution:
- First, we need to check eigenclass for singleton methods including inheritance of eigenclasses on class objects.
- Next, we need to check for instance methods and instance methods for any included modules.
- Next, we need to check instance methods, instance methods for any included modules in inheritance hierarchy manner.
- Finally, we need to invoke “method_missing” by following the above steps from 1-3, resolving to kernel “method_missing” if it is not found.
7. Explain the role of thread pooling with respect to thread lifecycle in Ruby?
In Ruby, the lifecycle of a thread starts automatically whenever CPU resources are available. Each thread runs the code block when it is instantiated and executes all expression/ statements in the block, obtains the final value of expression statements and returns it. Threads will work by using CPU resources but running multiple threads at a time will improve application performance.
Whereas in Thread pooling, multiple pre-instantiated reusable threads are created and kept on standby. These threads will be ready to perform tasks whenever needed. Thread pooling technique is best used when there are large numbers of necessary small tasks that must be executed. Thread pooling overhead of creating new threads for every new task is avoided.
Let us move to the next Ruby Interview Questions And Answer.
8. What is the difference between Block, Proc, and Lambda in Ruby?
In General, calling lambda is similar to invoking a method where a return statement will be returned but whereas in lambda, return statement will be return from lambda itself instead of returning from lexically enclosed block such as proc do. Lambda must be invoked with an exact number of arguments whereas procs are flexible in handling arguments. This is the advanced Ruby Interview Questions which is asked in an interview.
Block is ruby’s version of a closure statement – block of code which can be wrapped into a proc that can be stored in a variable or return to a method or passed as an argument to a method.
9. What is the difference between calling super and super() in Ruby?
In Ruby, calling super invokes the parent method with the same arguments as passed to child method. If arguments passed to the child don’t match what parent is expecting then an error will be thrown.
In Ruby, calling super () invokes the parent method without any arguments, as expected. As always, being explicit in code is good.
10. What is the difference between nil and false in Ruby?
- In Ruby, nil cannot be a value whereas false can be a value.
- Nil is not a Boolean data type whereas false is a Boolean data type.
- Nil is an object of nil class whereas false is an object of a false class.
- Nil will be returned when there is no predicate whereas false will be returned when predicting the present.
I hope you will have a good understanding of Ruby after going through this article and it will be helpful to prepare for the Ruby Interview Questions and crack it.
This has been a guide to List Of Ruby Interview Questions and Answers so that the candidate can crackdown these Ruby Interview Questions easily. Here in this post, we have studied about top Ruby Interview Questions which are often asked in interviews. You may also look at the following articles to learn more –