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Introduction

In this section, we will explore the fundamental concepts of variables and data types in Ruby. Understanding these basics is crucial as they form the foundation for more complex programming tasks.

Variables

Variables are used to store data that can be referenced and manipulated in a program. In Ruby, you don't need to declare the type of a variable explicitly; Ruby is dynamically typed.

Declaring Variables

To declare a variable, simply assign a value to a variable name:

name = "Alice"
age = 30
is_student = true

Variable Naming Conventions

Variable names should start with a lowercase letter or an underscore.
Use snake_case for multi-word variable names.
Avoid using reserved words (e.g., class, def, end).

Example

first_name = "John"
last_name = "Doe"
full_name = first_name + " " + last_name
puts full_name  # Output: John Doe

Data Types

Ruby supports several basic data types, including:

Numbers
Strings
Symbols
Booleans
Arrays
Hashes

Numbers

Ruby has two main types of numbers: integers and floating-point numbers.

Integers

age = 25
year = 2023

Floating-Point Numbers

price = 19.99
pi = 3.14159

Strings

Strings are sequences of characters enclosed in single or double quotes.

greeting = "Hello, World!"
name = 'Alice'

String Interpolation

You can embed variables inside strings using #{}.

name = "Alice"
greeting = "Hello, #{name}!"
puts greeting  # Output: Hello, Alice!

Symbols

Symbols are immutable, reusable constants represented with a colon (:) followed by a name.

status = :active

Booleans

Booleans represent true or false values.

is_student = true
is_employed = false

Arrays

Arrays are ordered collections of objects.

numbers = [1, 2, 3, 4, 5]
names = ["Alice", "Bob", "Charlie"]

Hashes

Hashes are collections of key-value pairs.

person = { name: "Alice", age: 30, city: "New York" }

Practical Examples

Example 1: Working with Numbers

a = 10
b = 20
sum = a + b
puts "The sum of #{a} and #{b} is #{sum}"  # Output: The sum of 10 and 20 is 30

Example 2: Using Arrays

fruits = ["apple", "banana", "cherry"]
puts fruits[0]  # Output: apple
puts fruits[1]  # Output: banana
puts fruits[2]  # Output: cherry

Example 3: Hashes and Symbols

person = { name: "Alice", age: 30, city: "New York" }
puts person[:name]  # Output: Alice
puts person[:age]   # Output: 30
puts person[:city]  # Output: New York

Exercises

Exercise 1: Variable Assignment

Assign values to variables and print them.

# Assign values to variables
name = "John"
age = 25
is_student = true

# Print the variables
puts "Name: #{name}"
puts "Age: #{age}"
puts "Is Student: #{is_student}"

Exercise 2: Array Manipulation

Create an array of your favorite fruits and print each fruit.

# Create an array of fruits
fruits = ["apple", "banana", "cherry"]

# Print each fruit
fruits.each do |fruit|
  puts fruit
end

Exercise 3: Hash Creation

Create a hash to store information about a book and print each key-value pair.

# Create a hash for a book
book = { title: "1984", author: "George Orwell", year: 1949 }

# Print each key-value pair
book.each do |key, value|
  puts "#{key.capitalize}: #{value}"
end

Solutions

Solution 1: Variable Assignment

name = "John"
age = 25
is_student = true

puts "Name: #{name}"
puts "Age: #{age}"
puts "Is Student: #{is_student}"

Solution 2: Array Manipulation

fruits = ["apple", "banana", "cherry"]

fruits.each do |fruit|
  puts fruit
end

Solution 3: Hash Creation

book = { title: "1984", author: "George Orwell", year: 1949 }

book.each do |key, value|
  puts "#{key.capitalize}: #{value}"
end

Conclusion

In this section, we covered the basics of variables and data types in Ruby. We learned how to declare variables, the different data types available, and how to use them in practical examples. Understanding these concepts is essential for progressing to more advanced topics in Ruby programming.

Variables and Data Types