Question

我有哈希部门

{"Mechnical" => {"boys" => "25", "girls"=>"5"}, "Civil"=> {"boys"=>"18", "girls"=>"12"}}

我想要这样的输出，

{"Mechanical" => "30", "Civil => "30"}

Answer 1

执行以下操作

# If you are in Ruby 2.1 or greater
your_hash.map { |k,v| [k, v.reduce(0) { |sum, (_, v)| sum + v.to_i }] }.to_h
# => {"Mechnical"=>30, "Civil"=>30} 

# below Ruby 2.1
Hash[your_hash.map { |k,v| [k, v.reduce(0) { |sum, (_, v)| sum + v.to_i }] }]
# => {"Mechnical"=>30, "Civil"=>30}

# for all versions
your_hash.each_with_object({}) do |(k,v), h| 
  h[k] = v.reduce(0) { |sum, (_, v)| sum + v.to_i }
end
# => {"Mechnical"=>30, "Civil"=>30}

Answer 2

h = { "Mechnical" => {"boys" => "25", "girls"=>"5"},
      "Civil"=> {"boys"=>"18", "girls"=>"12"} } 

h.map { |k, v| [k, v.values.map(&:to_i).sum] }.to_h
# => {"Mechnical"=>30, "Civil"=>30}

或者

Hash[ h.map { |k, v| [k, v.values.map(&:to_i).sum]} ]
# => {"Mechnical"=>30, "Civil"=>30}

由于您使用的是Rails，sum可以使用，其他明智的使用inject(:+)

Ruby：获取嵌套哈希值的总和

2 个答案: