Allows for reverse merging where its the keys in the calling hash that wins over those in the other_hash. This is particularly useful for initializing an incoming option hash with default values: 

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

The default :size and :velocity is only set if the options passed in doesn‘t already have those keys set.

Methods
Public Instance methods
reverse_merge(other_hash)

Performs the opposite of merge, with the keys and values from the first hash taking precedence over the second.

[ show source ]

    # File lib/active_support/core_ext/hash/reverse_merge.rb, line 14
14:         def reverse_merge(other_hash)
15:           other_hash.merge(self)
16:         end
reverse_merge!(other_hash)

Performs the opposite of merge, with the keys and values from the first hash taking precedence over the second. Modifies the receiver in place.

This method is also aliased as reverse_update

[ show source ]

    # File lib/active_support/core_ext/hash/reverse_merge.rb, line 20
20:         def reverse_merge!(other_hash)
21:           replace(reverse_merge(other_hash))
22:         end
reverse_update(other_hash)

Alias for reverse_merge!