## Rubies 1.9

## Hashes in Ruby 1.9 is respecting and remembering the order of the keys.

>> h = {1 => 2, 3 => 4, 5 => 6}
=> {1=>2, 3=>4, 5=>6}

>> h.keys
=> [1, 3, 5]

>> h.values
=> [2, 4, 6]

##

>> h[7] = 8
=> 8

>> h
=> {1=>2, 3=>4, 5=>6, 7=>8}

>> h.keys
=> [1, 3, 5, 7]

>> h.values
=> [2, 4, 6, 8]

##

>> h[1] = 20
=> 20

>> h.keys
=> [1, 3, 5, 7]

>> h.values
=> [20, 4, 6, 8]

## Syntax to write keys as symbol

# Instead of (in ruby 1.8):

>> h = { :a => 1, :b => 2, :c => 3 }
=> {:a=>1, :b=>2, :c=>3}

# You can also write (in ruby 1.9):

>> h = { a: 1, b: 2, c: 3 }
=> {:a=>1, :b=>2, :c=>3}

## How will it be valuable? See:

>> class Person
>>   attr_accessor :name, :age
>>
?>   def initialize(data)
>>     @name, @age = data.values_at(:name, :age)
>>   end
>> end
=> nil

>> david = Person.new(name: "David", age: 50)
=> #<Person:0x000001008532b0 @name="David", @age=50>

>> puts "#{david.name} is a youthful #{david.age}."
David is a youthful 50.
=> nil