1. What is Elixir?
Elixir is a functional, concurrent, general-purpose programming language that runs on the Erlang VM.
2. Why is Elixir considered a functional programming language?
Elixir emphasizes immutability and first-class functions, which are key principles of functional programming.
3. What is the purpose of the 'mix' tool in Elixir?
The 'mix' tool is used to create, compile, and manage Elixir projects.
4. How do you define a module in Elixir?
A module in Elixir is defined using the 'defmodule' keyword followed by the module name.
5. What is pattern matching in Elixir?
Pattern matching is a powerful feature in Elixir that allows you to match and destructure data.
6. How do you define a function in Elixir?
Functions in Elixir are defined using the 'def' keyword inside a module.
7. What is the pipe operator (|>) in Elixir?
The pipe operator is used to chain function calls, passing the result of one function as the input to the next.
8. What is an atom in Elixir?
An atom is a constant whose value is its own name, often used as identifiers.
9. How do you create a list in Elixir?
Lists in Elixir are created using square brackets, e.g., [1, 2, 3].
10. What is the difference between a list and a tuple in Elixir?
Lists are linked lists, while tuples are fixed-size collections stored contiguously in memory.
11. How do you handle concurrency in Elixir?
Concurrency in Elixir is handled using lightweight processes and the Actor model.
12. What is the purpose of the 'Enum' module in Elixir?
The 'Enum' module provides functions for working with enumerables like lists and maps.
13. How do you define a map in Elixir?
Maps in Elixir are defined using the %{} syntax, e.g., %{key: value}.
14. What is the purpose of the 'iex' shell in Elixir?
The 'iex' shell is an interactive Elixir shell used for testing and debugging code.
15. What is immutability in Elixir?
Immutability means that data cannot be changed once created; instead, new data structures are created.
16. Explain the concept of Supervisors in Elixir.
Supervisors are processes that monitor other processes to ensure fault tolerance by restarting them if they fail.
17. What is the difference between 'GenServer' and 'Task' in Elixir?
'GenServer' is used for long-lived processes with state, while 'Task' is for short-lived asynchronous operations.
18. How do you define a struct in Elixir?
A struct is a special map with a defined set of keys and default values, created using 'defstruct' inside a module.
19. What is the purpose of the 'Agent' module in Elixir?
The 'Agent' module provides a simple abstraction for managing state in a process.
20. How does Elixir handle error recovery?
Elixir uses the 'let it crash' philosophy with Supervisors to recover from errors by restarting processes.
21. What is the difference between 'spawn' and 'spawn_link' in Elixir?
'spawn' creates a new process, while 'spawn_link' creates a process linked to the parent for error propagation.
22. How do you use the 'Stream' module in Elixir?
The 'Stream' module is used for lazy enumeration, allowing you to work with potentially infinite data streams.
23. What is the purpose of the 'Protocol' feature in Elixir?
Protocols enable polymorphism by defining a set of functions that can be implemented for different data types.
24. How do you implement a behaviour in Elixir?
A behaviour is implemented by defining a module that adheres to the callbacks specified in the behaviour.
25. What is the purpose of the 'Registry' module in Elixir?
The 'Registry' module provides a way to register and look up processes by name.
26. How do you use ETS (Erlang Term Storage) in Elixir?
ETS is used for in-memory storage of large amounts of data, accessible by multiple processes.
27. What is the difference between 'send' and 'cast' in Elixir?
'send' is used for sending messages to processes, while 'cast' is an asynchronous call in 'GenServer'.
28. How do you use macros in Elixir?
Macros are used to write metaprogramming code by transforming abstract syntax trees at compile time.
29. What is the purpose of the 'Task.async' function in Elixir?
'Task.async' is used to start a task and retrieve its result asynchronously.
30. How do you use the 'with' construct in Elixir?
The 'with' construct is used for chaining multiple pattern matches and handling errors in a clean way.
31. What is the purpose of the OTP framework in Elixir?
The OTP framework provides tools and libraries for building robust, fault-tolerant, and scalable applications.
32. How do you implement a custom protocol in Elixir?
A custom protocol is implemented by defining a protocol using 'defprotocol' and providing implementations for specific data types using 'defimpl'.
33. What is the role of the 'DynamicSupervisor' in Elixir?
The 'DynamicSupervisor' is used to manage a dynamic set of child processes, allowing you to add or remove children at runtime.
34. How does Elixir achieve fault tolerance?
Elixir achieves fault tolerance through Supervisors, which monitor processes and restart them if they fail.
35. What is the difference between 'GenServer.call' and 'GenServer.cast'?
'GenServer.call' is synchronous and waits for a reply, while 'GenServer.cast' is asynchronous and does not wait for a reply.
36. How do you use the 'GenStage' module in Elixir?
The 'GenStage' module is used to build concurrent and data-driven workflows by defining producers, consumers, and producer-consumers.
37. What is the purpose of the 'Flow' library in Elixir?
The 'Flow' library is used for parallel and distributed data processing, built on top of 'GenStage'.
38. How do you implement a stateful process in Elixir?
A stateful process is implemented using 'GenServer', where the state is maintained in the process loop.
39. What is the purpose of the 'Node' module in Elixir?
The 'Node' module provides functions for interacting with distributed nodes in a cluster.
40. How do you handle inter-process communication in Elixir?
Inter-process communication is handled using message passing with 'send' and 'receive' constructs.
41. What is the difference between 'Agent' and 'GenServer' in Elixir?
'Agent' is a simpler abstraction for state management, while 'GenServer' provides more control and flexibility for implementing server processes.
42. How do you use the 'Registry' module for process lookup in Elixir?
The 'Registry' module allows you to register processes with unique keys and look them up by those keys.
43. What is the purpose of the 'Supervisor.Spec' module in Elixir?
The 'Supervisor.Spec' module (deprecated in newer versions) was used to define child specifications for Supervisors.
44. How do you implement a distributed task in Elixir?
A distributed task can be implemented using 'Task.async/1' or 'Task.async/3' with a specific node as the target.
45. What is the purpose of the 'Logger' module in Elixir?
The 'Logger' module is used for logging messages with different levels like debug, info, warn, and error.
46. How do you use the 'Mix.Config' module in Elixir?
The 'Mix.Config' module is used to manage application configuration in Elixir projects.
47. What is the purpose of the 'Application' module in Elixir?
The 'Application' module is used to define and manage the lifecycle of an application, including starting and stopping processes.
48. How do you implement a custom behaviour in Elixir?
A custom behaviour is implemented by defining a module with 'defcallback' and creating modules that implement the specified callbacks.
49. What is the purpose of the 'Task.Supervisor' module in Elixir?
The 'Task.Supervisor' module is used to supervise tasks, ensuring fault tolerance and process management.
50. How do you use the 'ExUnit' framework in Elixir?
The 'ExUnit' framework is used for writing and running tests in Elixir, providing features like assertions and test case organization.