each_with_object.rb

# Inject
%w{earl-grey peach white}.inject({}) do |hash, string| 
  hash[string] = "tea"
  hash
end

=> {"white"=>"tea", "earl-grey"=>"tea", "peach"=>"tea"}

# Each with object
>> %w{earl-grey peach white}.each_with_object({}){|string, hash| hash[string] = "tea"}
=> {"white"=>"tea", "earl-grey"=>"tea", "peach"=>"tea"}

# Inject: fails unless we return the accumulator.
>> %w{earl-grey peach white}.inject({}){|hash, string| hash[string] = "tea"}
IndexError: string not matched
        from (irb):4:in `[]='
        from (irb):4
        from (irb):4:in `inject'
        from (irb):4:in `each'
        from (irb):4:in `inject'
        from (irb):4