Method: Hash#reverse_merge

Defined in:
lib/active_support/core_ext/hash/reverse_merge.rb

#reverse_merge(other_hash) ⇒ Object

Allows for reverse merging two hashes where the keys in the calling hash take precedence over those in the other_hash. This is particularly useful for initializing an option hash with default values:

def setup(options = {})
  options.reverse_merge! :size => 25, :velocity => 10
end

Using merge, the above example would look as follows:

def setup(options = {})
  { :size => 25, :velocity => 10 }.merge(options)
end

The default :size and :velocity are only set if the options hash passed in doesn’t already have the respective key.



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# File 'lib/active_support/core_ext/hash/reverse_merge.rb', line 17

def reverse_merge(other_hash)
  other_hash.merge(self)
end