ruby - 从哈希键转移值

Question

我有这个价值 {:cat=>["cat1", "cat2", "cat3"], :dog=>["dog1", "dog2", "dog3"]}

我希望从每个键中检索/移位值：

IE：

得到以下内容：

[{:cat => "cat1", :dog => "dog1"}, {:cat => "cat2", :dog => "dog2"} ... etc]

我真的不确定解决这个问题的最佳方法，有什么建议吗？

编辑：

到目前为止，我有：

a[a.keys.first].dup.map{|c| a.map{|index, vals| vals.shift}}   
# => [["cat1", "dog1"], ["cat2", "dog2"], ["cat3", "dog3"]] 

虽然由于缺少钥匙而不是我想要的。

Answer 1

那这个呢？

a = {:cat=>["cat1", "cat2", "cat3"], :dog=>["dog1", "dog2", "dog3"]}

a1 = a.each_with_object({}) do |(k, vals), memo|
  shifted = vals.shift
  memo[k] = shifted
end

a # => {:cat=>["cat2", "cat3"], :dog=>["dog2", "dog3"]}
a1 # => {:cat=>"cat1", :dog=>"dog1"}

Answer 2

不修改原始哈希：

h = {:cat=>["cat1", "cat2", "cat3"], :dog=>["dog1", "dog2", "dog3"]}

h.values.first.zip(h.values.last).map do |value_pair| 
  Hash[ h.keys.zip(value_pair) ]
end

# => [{:cat=>"cat1", :dog=>"dog1"}, {:cat=>"cat2", :dog=>"dog2"}, {:cat=>"cat3", :dog=>"dog3"}]

h
# => {:cat=>["cat1", "cat2", "cat3"], :dog=>["dog1", "dog2", "dog3"]}

数组#zip：http ://www.ruby-doc.org/core-1.9.3/Array.html#method-i-zip

Answer 3

h = {:cat=>["cat1", "cat2", "cat3"], :dog=>["dog1", "dog2", "dog3"]}

ks = h.keys
h.values.transpose.map{|vs| Hash[[ks, vs].transpose]}
# => [
#   {:cat => "cat1", :dog => "dog1"},
#   {:cat => "cat2", :dog => "dog2"},
#   {:cat => "cat3", :dog => "dog3"}
# ]

或者，强烈推动单线，稍微牺牲速度：

h.values.transpose.map{|vs| Hash[[h.keys, vs].transpose]}

Answer 4

cats_and_dogs = {:cat=>["cat1", "cat2", "cat3"], :dog=>["dog1", "dog2", "dog3"]}

cats_with_dogs = []
i = 0
cats_and_dogs[:cat].each do |e|
    cats_with_dogs << {cat: cats_and_dogs[:cat][i], dog: cats_and_dogs[:dog][i]}
    i+=1
end

cats_with_dogs # [{:cat=>"cat1", :dog=>"dog1"}, {:cat=>"cat2", :dog=>"dog2"}, {:cat=>"cat3", :dog=>"dog3"}]