test.rb

#Is the line of code below valid Ruby code? If so, what does it do? Explain your answer.

 -> (a) {puts a}["Hello world"]

# #Write a function that sorts the keys in a hash by the length of the key as a string;
#should return ["abc", "4567", "another_key"]

hsh = { abc: 'hello', 'another_key' => 123, 4567 => 'third' }
hsh.sort_by { |key| key.to_s.length }

# #Can you call a private method outside a Ruby class using its object?
 class Test
    def foo
      p "Public method"
    end
    
    private
    def method
      p "I am a private method"
    end
 end
 
 test = Test.new
 test.send(:method)
 
# #Find duplicates

arr = ["A", "B", "C", "B", "A"]
counted_items = Hash.new(0)
arr.each { |elem| counted_items[elem] += 1}

#What’s the following program going to print?
x = 1
class MyClass
  y = 2
  def foo
    z = 4
    y ||= 0
    puts z + y
  end
  
  define_method :bar do |x|
    z = 5
    y ||= 0
    puts z + y + x
  end
end
my_class = MyClass.new


my_class.foo #=> 6
my_class.bar(10) #=> 17
my_class.bar #=> Error

#Write a single line of Ruby code that prints the Fibonacci sequence of any length as an array.