Ruby Cheatsheet

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The Ruby Cheatsheet provides the fundamentals of Ruby programming. It helps students and developers to build the projects and prepare for the interviews. Go through the cheat sheet and learn the concepts. Thus, this improves the coding skills.

1. Basic Syntax

This is the basic syntax of the Ruby programming language that displays the text using puts and print.

puts "Hello, World!"
print "Tutorialspoint!"

2. Variables

Variables are used for the memory location. Ruby supports various types of variable −

# Defining the variables
x = 10 # integer
y = 20.5 # float
puts x + y

3. Operators

The operators are the symbol that tells the compiler to perform logical tasks.

Operators Description Example
Arithmetic Operators This is basic mathematical operations. 'a + b', 'a - b', 'a * b', 'a / b', 'a % b'
Relational Operators This compares two values. 'a == b', 'a != b', 'a > b', 'a < b', 'a >= b', 'a <= b'
Logical Operators This combine the conditional statements. 'a && b', 'a || b', '!a'
Bitwise Operators This perform in the bit level. 'a & b', 'a | b', 'a ^ b', '~a', 'a << b', 'a >> b'
Assignment Operators This assign the values to the variables. 'a = b', 'a += b', 'a -= b', 'a *= b', 'a /= b', 'a %= b'

Below are the some examples of operators in Ruby programming language −

# Arithmetic Operators
# Addition
puts 8 + 18 
# Subtraction  
puts 9 - 3 
# Multiplication  
puts 7 * 6   
# Division
puts 20 / 4   

# Comparison Operators
# Greater than
puts 10 > 5 
# Equal to  
puts 10 == 5  
# Not equal to
puts 10 != 5

4. Comments

Comments are used to show the information. The single-line comment is denoted by "#" whereas multi-line comments are written using the =begin and =end keywords.

# This is a single-line comment
=begin
multi-line comment
=end

5. String

The strings are used to print the text. In Ruby, strings are represented using both single and double quotes.

# Strings
str1 = "Hello"
str2 = 'World!'
puts str1 + " " + str2

6. String Interpolation

The string interpolation is the process of inserting the values with the help of expression inside the curly braces #{}.

name = "Tutorialspoint!"
puts "Welcome to #{name}!"

7. If-else Statement

The if-else statement is a part of the control structure used to execute the logic conditionally, based on whether the condition is true or false.

age = 18
if age >= 18
  print "You are eligible for vote."
else
  print "You are are not eligible for vote."
end

8. Classes and Objects

Classes and objects are fundamental concepts of object-oriented programming. A class defines the blueprint for an object, whereas an object is an instance of a class.

class Person
  def initialize(name, id)
    @name = name
    @id = id
  end

  def fun
    puts "My name is #{@name} and I am #{@id} years old."
  end
end

person = Person.new("Sanjay", 25)
person.fun

9. break Statements

In Ruby, the break statement terminates the program loop.

num = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
num.each do |num|
  if num == 7
    puts "The loop break at the number #{num}"
    break
  end
  puts "The processing number is #{num}"
end
puts "Loop ended."

10. Ruby Blocks

The blocks represent the anonymous function in Ruby that is passed into the methods. The block can be declared using a single-line or multi-line block.

times { puts "Hello, Block!" }

11. Modules

In Ruby, a module is a collection of methods and constants that can be used to organize and structure code.

# example of modules
module MathHelpers
  def square(x)
    x * x
  end
end

include MathHelpers
puts square(4)

12. Array

In Ruby, an array defines the ordered, indexed collection of objects. The object holds the data types such as String, Integer, Fixnum, Hash, Symbol, and even other Array objects.

arr = [10, 20, 30, 40, 50]
arr.each { |i| puts i }

13. Hashes

The hashes are similar to dictionaries by defining key−value pairs.

hash = { name: "Ruby", id: 3323 }
puts hash[:name]

14. Ranges

The ranges are data types that show a sequence of values.

(1..5).each { |i| puts i }

15. Regular Expression

Regular Expression is defined by the special sequence of characters that help users to find the set of string matches or particular syntax held in the program.

/pattern/
/pattern/im    # option can be specified
%r!/usr/local! # general delimited regular expression

16. Exception Handling

In Ruby, an exception handling is the process of handling the error raised in the program. These errors occur during the execution of the program. In simple, unexpected, or unwanted events.

begin
    raise
      # block where exception raise

    rescue
      # block where exception rescue
end

17. Commonly Used Library

Here, we are providing the example of the JSON library.

require 'json'
data = { name: "Ruby", type: "Programming Language" }
puts JSON.generate(data)
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