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ActiveSupport::OrderedHash

v3.2.13 - Show latest stable - Superclass: Array

The order of iteration over hashes in Ruby 1.8 is undefined. For example, you do not know the order in which keys will return keys, or each yield pairs. ActiveSupport::OrderedHash implements a hash that preserves insertion order, as in Ruby 1.9:

oh = ActiveSupport::OrderedHash.new
oh[:a] = 1
oh[:b] = 2
oh.keys # => [:a, :b], this order is guaranteed

ActiveSupport::OrderedHash is namespaced to prevent conflicts with other implementations.

Files

  • activesupport/lib/active_support/ordered_hash.rb

1Note

Superclass of OrderedHash

mcmire ยท Apr 8, 20096 thanks

Note that in Rails 2.3, OrderedHash changed from being a subclass of Array to a subclass of Hash. This is contrary to what the documentation says above.