ruby - 如何合并 Ruby 哈希

Question

如何合并这两个哈希:

{:car => {:color => "red"}}
{:car => {:speed => "100mph"}}

得到:

{:car => {:color => "red", :speed => "100mph"}}

Answer 1

有一个Hash#merge方法:

ruby-1.9.2 > a = {:car => {:color => "red"}}
 => {:car=>{:color=>"red"}} 
ruby-1.9.2 > b = {:car => {:speed => "100mph"}}
 => {:car=>{:speed=>"100mph"}} 
ruby-1.9.2 > a.merge(b) {|key, a_val, b_val| a_val.merge b_val }
 => {:car=>{:color=>"red", :speed=>"100mph"}} 

如果你需要合并嵌套的哈希，你可以创建一个递归方法:

def merge_recursively(a, b)
  a.merge(b) {|key, a_item, b_item| merge_recursively(a_item, b_item) }
end

ruby-1.9.2 > merge_recursively(a,b)
 => {:car=>{:color=>"red", :speed=>"100mph"}}