Loading…

Elixir Interview Questions and Answers

By Admin
Last update: 16 May 2020, 21 Questions
Elixir Interview Questions

Elixir is a functional and dynamic language that is designed for building scalable applications. It is based on Erlang language VM which is known for running fault-tolerant and low-latency systems. Erlang was written in 1986 by Ericsson to help address fault-tolerance and concurrency. Offering useful tooling and extensible design, Elixir is supported by meta-programming and polymorphism.

Development History

Elixir was created in 2012 by Jose Valim on top of the Erlang VM called BEAM.

Latest Version: he latest version is 1.7.3 which was released in August 2018.

Advantages

  • Scalability and Extensibility
  • Fault Tolerance
  • Interactive and fast development
  • Strong metaprogramming
  • Simple syntax

Most Frequently Asked Elixir Interview Questions

1. What is Elixir? Explain

Elixir is a functional and dynamic language that is designed for building scalable applications. It is based on Erlang language VM which is known for running fault-tolerant and low-latency systems. Offering useful tooling and extensible design, Elixir is supported by meta-programming and polymorphism.

2. Explain the advantages of Elixir.
  • Scalability and Extensibility
  • Fault Tolerance
  • Interactive and fast development
  • Strong metaprogramming
  • Simple syntax
3. What is the latest version of Elixir?

The latest version is 1.7.3 which was released in August 2018.

4. How many types of data types does Erlang provide?

Erlang provides two types of data types:

  • Constant data type: This data type cannot be split into primitive subtypes as it consists of Atoms and Numbers.
  • Compound data type: This data type is used to put together other data types, and it consists mainly of lists and tuples.
5. What is Open Telecom Platform (OTP)?

An open source platform, OTP is a huge set of Erlang libraries to do all kinds of tasks, from assembling ASN.1 to providing a server.

6. How is run time error handled in Erlang?

Using Catch or Try can help prevent run-time errors from causing the process to terminate. Catch Expr throws value of the expression, except when an exception occurs during the evaluation phase. Try Exprs is nothing but the enhancement of catch with the added ability to identify and handle the desired exception class.

7. What are the modules? How can a module be stored?

Erlang enables to put together code into modules, which consists of functions. A module introduces local scope of functions, both Public and Private. A module is stored in a file named “.erl.” Make sure the file basename and the name of the module are the same.

8. How is a “process” created in Erlang?

A process is created by calling spawn, which forms a process and returns the pid. Here’s how you can do it:

Spawn (Module, Name, Args ) -> pid ()

9. What is guard sequence?

The function clauses can be protected using guards, but a clause can only be protected if the guard holds it. A guard sequence is separated by a comma (,) and semicolon (;). The guard sequence can only be true when at least one guard is true.

10. What are some of the valid guard expressions?

The valid guard expressions are Atom true, Other constants, Calls to the BIFs specified, Term Comparisons, Arithmetic Expressions, Boolean Expressions, and Short-circuit Expressions.

11. How is a message sent and received in Erlang?

For sending a message, you can use an exclamation mark (!) as the operator. The syntax that you can use for sending a new message is Pid ! Message.

For receiving a message, you can use Pattern Matching from the message queue receive a statement.

13. What is the syntax to write Macros?

define ( Const, Replacement )

define ( Fun ( Var1 , Var2, …., Var ) , Replacement )

14. What are some of the pre-defined Macros in Erlang?

Here are the pre-defined Macros:

  • ? Module returns the name of the existing module.
  • ? Module_String returns the name of the existing module as a string.
  • ? File returns the existing file name.
  • ? Line returns the existing line number
  • ? Machine returns the existing machine name, ‘BEAM.’
15. What is a record?

The data structure that is used for storing a fixed number of elements is referred to as a record. Expressions are then translated into tuple expressions during the compilation record.

The Record is defined by the name of the record, which is followed by the field names. The record and field names should be atoms.

record (Name, { Field1 [= Value] , … FieldN [= ValueN] } )

16. What is the command for accessing record field?

Expr#Name.Field. This command returns the value of the mentioned field. To return the position of the specified field, you can use the command #Name.Field.

17. What is Erlang Port Mapper Daemon (epmd)?

It is a small server that is used for establishing distributed communications. This name server is responsible for mapping the node names to the machine addresses.

18. What are the main operators in Elixir?

Following are the main operators:

  • Arithmetic operators
  • Comparison operators
  • Boolean operators
  • Misc operators
19. What is String Interpolation?

It is a way to build a new string value where the code is wrapped in curly braces and ‘#’ function.

Example

                                                    

x = "Apocalypse"
y = "X-men #{x}"
IO.puts(y)
x = "Apocalypse"
y = "X-men #{x}"
IO.puts(y)

20. What role does Crypto Module play? The crypto module decrypts project applications by using digital signature and hashing function and.

Example

                                                    

IO.puts(Base.encode16(:crypto.hash(:sha256, "Elixir")))

IO.puts(Base.encode16(:crypto.hash(:sha256, "Elixir")))

21. Define Structs.

You can define Structs by using the defstruct. Here is how you can do it:

Example

                                                    

iex> defmodule User do
...> defstruct name: "John", age: 27
...> end
iex> defmodule User do
...> defstruct name: "John", age: 27
...> end