array.rb

cities = ["london", "paris", "berlin"]
#         0         1        2
# CREATE
# cities.push("olso")
cities << "madrid"

# READ
# p cities.last
p cities[3]

# UPDATE
cities[1] = "Marseille"

# DELETE
# cities.delete("london")
cities.delete_at(0)

# p cities


# HASHES
paris = {
  country: "France",
  population: 2230301
}

# CREATE
paris[:monument] = "Eiffel Tower"

# UPDATE
paris[:country] = "Italy"

# READ
paris[:population]

# DELETE
paris.delete("country")

paris.each do |key, value|
  puts "the #{key} is #{value}"
end

hash.rb

# students =     [ "Peter", "Mary", "George", "Emma" ]
# student_ages = [ 24     , 25    , 22      ,  20    ]
# #                0        1       2          3

# # Peter is 24 years old
# # Mary is 25 years old
# # [...]

# students.each_with_index do |student, index|
#   puts "#{student} is #{student_ages[index]} years old"
# end

students = {
  "Peter" => 24,
  "Mary" => 25,
  "George" => 22
}

students.each do |student_name, student_age|
  puts "#{student_name} is #{student_age} years old"
end

hash_method.rb

def tag(tag_name, content, attributes)
  str = ""

  attributes.each do |key, value|
    str += " #{key}='#{value}'"
    # key="value"
  end

  return "<#{tag_name}#{str}>#{content}</#{tag_name}>"
end


puts tag("h1", "Hello", {})
puts tag("div", "Hello", {class: "text-blue", id: "banner"})
# <h1>Hello</h1>
# <p class="text-blue">This is a paragraph</p>
# <div id="banner" class="text-center">Hello</div>