Ruby：使用來自其他哈希的匹配值來交換哈希密鑰

Question

我有這些哈希：

hash  = {1 => "popcorn", 2 => "soda"}
other_hash = {1 => "dave", 2 => "linda", 3 => "bobby_third_wheel"}

我想將id引用替換為與第二個哈希中的id關聯的名稱，如果other_hash中有一條沒有任何內容匹配的記錄，則應該將其刪除到生成的哈希中。 像這樣：

the_one_hash_to_rule_them_all = {"dave" => "popcorn", "linda" => "soda"}

Answer 1

您可以在名稱上的“主”哈希中each_with_object使用此each_with_object方法。

other_hash.each_with_object({}) { |(id, name), h| h[name] = hash[id] if hash.key?(id) }
# => {"dave"=>"popcorn", "linda"=>"soda"}

Answer 2

hash.each_with_object({}){|(k,v), res| res[other_hash[k]] = v}
# => {"dave"=>"popcorn", "linda"=>"soda"}

Answer 3

首先，使用模式enumerable.map { expr if condition }.compact進行“數組理解”，最后使用Array#to_h 。

h = other_hash.map { |k, v| [v, hash[k]] if hash.has_key?(k) }.compact.to_h
#=> {"dave"=>"popcorn", "linda"=>"soda"}

也：

h = other_hash.select { |k, v| hash.has_key?(k) }.map { |k, v| [v, hash[k]] }.to_h

Answer 4

hash.map{|k, v| [other_hash[k], v]}.to_h
# => {"dave"=>"popcorn", "linda"=>"soda"}