Recently, I have to implement my own Hash sorting method. Not really with Hash but with ActiveSupport::OrderedHash
- I don’t like the way ActiveSupport::OrderedHash behaves with sorting functionality.
- It just behaves like a simple Hash
- I would like that sort return an ActiveSupport::OrderedHash not an Arrray!!! Why is it called OrderedHash in this case ?
- I would like to sort with keys only, not with an array [key, value]
Ok no matter, I implemented my own new SimpleOrderedHash :
require 'active_support/ordered_hash' class SimpleOrderedHash < ActiveSupport::OrderedHash # Lets reimplement sort method def sort(&block) h = self.dup h.sort!(&block) h end # Lets implement sort! method # It uses @keys variable to do the sorting def sort!(&block) @keys.sort!(&block) sync_keys! self end # A fancy inspect def inspect "#<#{self.class.name} #{Hash.instance_method(:inspect).bind(self).call}>" end end
You can now use it like that :
h = SimpleOrderedHash.new h.merge!({'second' => 1, 'first' => 5, 'third' => 2.5}) => #<SimpleOrderedHash {"third"=>2.5, "second"=>1, "first"=>5}> # sort return a SimpleOrderedHash result = h.sort do |a,b| h[a] <=> h[b] end => #<SimpleOrderedHash {"third"=>2.5, "second"=>1, "first"=>5}> # and order as I wanted result.each{ |k,v| puts v } 1 2.5 5 => ["second", "third", "first"] # sort! change internally the order of a SimpleOrderedHash h.sort! do |a,b| h[b] <=> h[a] end h.each{ |k,v| puts v } 5 2.5 1 => ["first", "third", "second"]
