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Ruby Interview Questions Cheat Sheet (DRAFT) by

This interview Q&A cheat sheet offers a quick, easy reference to key interview strategies and commonly asked questions. Use it to refresh your preparation and boost your confidence before any interview!

This is a draft cheat sheet. It is a work in progress and is not finished yet.

What is Ruby?

Ruby is a strongly object­-or­iented language, which means that absolutely everything in Ruby is an object, even the most basic data types.
- It is simple & readable language
- Implem­ented based on python and perl
- Ruby follows convention over config­uration and DRY

Convention Over Config­uration and DRY

COC: The method names and variable names should match the logic
DRY: If same code implements 2 or more scenario used method & called method

Method Overlo­ading & Method Overriding

Overlo­ading: A class containing more methods with same name with different parameters
Overriding: Parent class and child class having same name with differnt functi­ona­lities. when you call, it executes parent class only.

RVM(Ruby version Manager)

It is a command line tool allows easily to install, manage & work with different ruby enviro­nments
 

sub VS gsub

sub: It will replace first matching item
Ex: I love cats. cats are great
O/p: I love dogs. cats are great
gsub: It will replace all matching item in sentence
Ex: I love cats. cats are great
O/p: I love dogs. dogs are great

Hash VS Array

Hash: Key-Value pair combin­ation. Key should be unique
Array: Collection of stings, numbers. Index starts with '0'. It is Hetero­genous

Include VS Extend

Include: We need objects to call methods
Extend: We dont need to objects to call methods, directly we can call with class.

Class VS Module

Class: Class is a blueprint of object
Module: It is collection of class

Procs VS lamda

Proc(Proce­dure): It is code block that stored in local variable, not in method.
Lamda: It is Short block of code which takes in parameters & returns value.
 

Self

- Self refers to current object instance
- It is used to access methods & variables within object itself.

nil vs false

nil: Object represents nothing or no value
false: Boolean value that explicitly represents falsehood.

puts vs print vs p

puts: Output a string with newline at end.
print: Output a string without newline
p: Output value is more readable form, shows exact values including quotes.