gistfile1.txt

arr = [1,2,3,4,5]
arr.each { |n| n + 2 }
arr 
=> [1,2,3,4,5]
arr.map! { |n| n + 2 }
arr
=> 
[3,4,5,6,7]
arr.collect! { |n| n + 2 }
arr
=>
[3,4,5,6,7]
arr.select!{ |n| n > 2 }
arr
=>
[5,6,7]
arr.sum
=>
18
arr = [1,2,nil,8,nil}
arr.compact!
=>
[1,2,8]

["a", "b"].concat( ["c","d"] )
=>
["a","b","c","d"]
------

hash
-----

my_hash = Hash.new
my_hash = {}
my_hash.new(0)

my_hash[:name] = "velu"
my_hash[:age] = 22
 
movies = {
 Ravanan: 4.8,
 Thanioruvan: 4.5,
 payanangal: 4
}

puts "What would you like to do?"
puts "-- Type 'add' to add a movie."
puts "-- Type 'update' to update a movie."
puts "-- Type 'display' to display all movies."
puts "-- Type 'delete' to delete a movie."

choice = gets.chomp.downcase
case choice
when 'add'
  puts "What movie do you want to add?"
  title = gets.chomp
  if movies[title.to_sym].nil?
    puts "What's the rating? (Type a number 0 to 4.)"
    rating = gets.chomp
    movies[title.to_sym] = rating.to_i
    puts "#{title} has been added with a rating of #{rating}."
  else
    puts "That movie already exists! Its rating is #{movies[title.to_sym]}."
  end
when 'update'
  puts "What movie do you want to update?"
  title = gets.chomp
  if movies[title.to_sym].nil?
    puts "Movie not found!"
  else
    puts "What's the new rating? (Type a number 0 to 4.)"
    rating = gets.chomp
    movies[title.to_sym] = rating.to_i
    puts "#{title} has been updated with new rating of #{rating}."
  end
when 'display'
  movies.each do |movie, rating|
    puts "#{movie}: #{rating}"
  end
when 'delete'
  puts "What movie do you want to delete?"
  title = gets.chomp
  if movies[title.to_sym].nil?
    puts "Movie not found!"
  else
    movies.delete(title.to_sym)
    puts "#{title} has been removed."
  endmovies = {
 Ravanan: 4.8,
 Thanioruvan: 4.5,
 payanangal: 4
}

puts "What would you like to do?"
puts "-- Type 'add' to add a movie."
puts "-- Type 'update' to update a movie."
puts "-- Type 'display' to display all movies."
puts "-- Type 'delete' to delete a movie."

choice = gets.chomp.downcase
case choice
when 'add'
  puts "What movie do you want to add?"
  title = gets.chomp
  if movies[title.to_sym].nil?
    puts "What's the rating? (Type a number 0 to 4.)"
    rating = gets.chomp
    movies[title.to_sym] = rating.to_i
    puts "#{title} has been added with a rating of #{rating}."
  else
    puts "That movie already exists! Its rating is #{movies[title.to_sym]}."
  end
when 'update'
  puts "What movie do you want to update?"
  title = gets.chomp
  if movies[title.to_sym].nil?
    puts "Movie not found!"
  else
    puts "What's the new rating? (Type a number 0 to 4.)"
    rating = gets.chomp
    movies[title.to_sym] = rating.to_i
    puts "#{title} has been updated with new rating of #{rating}."
  end
when 'display'
  movies.each do |movie, rating|
    puts "#{movie}: #{rating}"
  end
when 'delete'
  puts "What movie do you want to delete?"
  title = gets.chomp
  if movies[title.to_sym].nil?
    puts "Movie not found!"
  else
    movies.delete(title.to_sym)
    puts "#{title} has been removed."
  end
else
  puts "Sorry, I didn't understand you."
end
else
  puts "Sorry, I didn't understand you."
end