Ruby Class Case

Ruby Class Case

The case statement in Ruby is used for more complex conditional flows where you might be used to using if...elsif...else. It's a way to replace multiple if statements and make your code more readable.

Here's a simple example of a case statement:

value = 2 case value when 1 puts "One" when 2 puts "Two" when 3 puts "Three" else puts "Something else" end

In this example, the case statement checks the value of value. Depending on the value, it executes a different when clause. If none of the when clauses match, it executes the else clause.

You can use the case statement with any kind of object, not just numbers. For example:

class Car attr_accessor :brand def initialize(brand) @brand = brand end def brand_type case @brand when "Toyota" "Japanese Car" when "Ford" "American Car" when "Ferrari" "Italian Car" else "Unknown Car" end end end car = Car.new("Ferrari") puts car.brand_type # outputs "Italian Car" car.brand = "Ford" puts car.brand_type # outputs "American Car"

In this example, the case statement is used to determine the type of car based on the brand.

The case statement is a powerful tool in Ruby, and it can make your code more readable when you're dealing with complex conditional logic. It can be used in any context, not just within classes, and with any type of object, not just strings or numbers.

Examples

  1. Ruby class definition:

    • Description: In Ruby, a class is defined using the class keyword. It encapsulates data and behavior into a single unit.
    • Code example:
      class Person def initialize(name, age) @name = name @age = age end def display_info puts "Name: #{@name}, Age: #{@age}" end end # Object instantiation person = Person.new("John", 25) person.display_info

  2. Ruby class inheritance:

    • Description: Inheritance allows a class to inherit attributes and methods from another class.
    • Code example:
      class Animal def speak puts "Animal speaks" end end class Dog < Animal def bark puts "Dog barks" end end # Object instantiation dog = Dog.new dog.speak # Inherited method dog.bark # Class-specific method

  3. Ruby class methods:

    • Description: Class methods are defined using the self keyword and can be called on the class itself.
    • Code example:
      class MathOperations def self.square(number) number * number end end # Using the class method result = MathOperations.square(5)

  4. Ruby case statement in class:

    • Description: A case statement in a class allows for multiple conditional branches based on the value of an expression.
    • Code example:
      class GradeClassifier def classify(grade) case grade when 'A' puts "Excellent" when 'B', 'C' puts "Good" else puts "Needs improvement" end end end # Using the class method classifier = GradeClassifier.new classifier.classify('B')

  5. Ruby switch case in class:

    • Description: The case statement is similar to a switch statement in other languages.
    • Code example:
      class TrafficLight def signal(color) case color when 'red' puts "Stop" when 'green' puts "Go" when 'yellow' puts "Proceed with caution" else puts "Invalid color" end end end # Using the class method traffic_light = TrafficLight.new traffic_light.signal('green')

  6. Ruby class example:

    • Description: An example of a simple Ruby class with methods and attributes.
    • Code example:
      class Car attr_accessor :make, :model def initialize(make, model) @make = make @model = model end def display_info puts "Make: #{@make}, Model: #{@model}" end end # Object instantiation car = Car.new("Toyota", "Camry") car.display_info

  7. Ruby class variables:

    • Description: Class variables are shared among all instances of a class and are prefixed with @@.
    • Code example:
      class Counter @@count = 0 def increment @@count += 1 end def display_count puts "Count: #{@@count}" end end # Object instantiation counter1 = Counter.new counter2 = Counter.new counter1.increment counter2.increment counter1.display_count # Outputs "Count: 2"

  8. Ruby class instance variables:

    • Description: Instance variables are specific to an instance of a class and are prefixed with @.
    • Code example:
      class Person def initialize(name) @name = name end def display_name puts "Name: #{@name}" end end # Object instantiation person = Person.new("Alice") person.display_name

  9. Ruby class access modifiers:

    • Description: Access modifiers (public, private, protected) control the visibility of methods in a class.
    • Code example:
      class BankAccount def deposit(amount) # Public method end private def withdraw(amount) # Private method end end

  10. Ruby class constructor:

    • Description: The constructor, often named initialize, is called when a new instance of a class is created.
    • Code example:
      class Book def initialize(title, author) @title = title @author = author end end # Object instantiation with constructor parameters book = Book.new("Ruby Programming", "John Doe")

  11. Ruby class initialization:

    • Description: Initialization is the process of setting up an object's initial state, often done in the constructor (initialize method).
    • Code example:
      class Circle def initialize(radius) @radius = radius end end # Object instantiation with initialization circle = Circle.new(5)

  12. Ruby class constants:

    • Description: Class constants are defined using uppercase letters and are accessible throughout the class.
    • Code example:
      class Constants PI = 3.14159 def circle_area(radius) PI * radius**2 end end # Using the class constant area = Constants.new.circle_area(3)

  13. Ruby class attributes:

    • Description: Attributes are often represented by instance variables and can be accessed using getter and setter methods or attr_accessor.
    • Code example:
      class Product attr_accessor :name, :price def initialize(name, price) @name = name @price = price end end # Object instantiation with attribute assignment product = Product.new("Laptop", 999) puts "Product: #{product.name}, Price: $#{product.price}"

  14. Ruby case-insensitive class comparison:

    • Description: When comparing strings in a case-insensitive manner, use methods like casecmp.
    • Code example:
      class StringComparison def compare_strings(str1, str2) result = str1.casecmp(str2) if result.zero? puts "Strings are equal" else puts "Strings are not equal" end end end # Using the class method comparer = StringComparison.new comparer.compare_strings("Ruby", "ruby") # Outputs "Strings are equal"

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