vendor/rails/activesupport/lib/active_support/core_ext/hash/diff.rb

   1 module ActiveSupport #:nodoc:
   2   module CoreExtensions #:nodoc:
   3     module Hash #:nodoc:
   4       module Diff
   5         # Returns a hash that represents the difference between two hashes.
   6         #
   7         # Examples:
   8         #
   9         #   {1 => 2}.diff(1 => 2)         # => {}
  10         #   {1 => 2}.diff(1 => 3)         # => {1 => 2}
  11         #   {}.diff(1 => 2)               # => {1 => 2}
  12         #   {1 => 2, 3 => 4}.diff(1 => 2) # => {3 => 4}
  13         def diff(h2)
  14           self.dup.delete_if { |k, v| h2[k] == v }.merge(h2.dup.delete_if { |k, v| self.has_key?(k) })
  15         end
  16       end
  17     end
  18   end
  19 end