Hash in ruby

Insert into Ruby Array

The following piece of code insert to each hash in the array a new element. I used destructive hash merge to add the new element to each hash in the array.

cities = [  
 {"Name" => "los angeles", "State" => "CA"},  
 {"Name" => "las vegas", "State" => "NV"},  
 {"Name" => "miami", "State" => "FL"}  
 ]  
 cities.map! { |c| c.merge!("Count" => 1) }  
 puts cities  

Iterate on Ruby hash (sorted and unsorted)

h = {”boy” => 1, “apple” => 2, “cat” => 3}

h.each {|key, value| puts "#{key} => #{value}"}

Will output:
cat => 3
boy => 1
apple => 2

Getting Value from Hash

inst_section = {
  :cello     => 'string',
  :clarinet => 'woodwind',
  :drum      => 'percussion',
  :oboe      => 'woodwind',
  :trumpet   => 'brass',
  :violin    => 'string'
}

inst_section[:trumpet] produces the output brass