从物化路径构建树
我在使用ruby从物化路径构建树结构时遇到了麻烦。
假设我有一个排序结果集（来自couchdb）：
[ { :key => [], :value => "Home" }, { :key => ["about"], :value => "About" }, { :key => ["services"], :value => "Services" }, { :key => ["services", "plans"], :value => "Plans" }, { :key => ["services", "training"], :value => "Training" }, { :key => ["services", "training", "python"], :value => "Python" }, { :key => ["services", "training", "ruby"], :value => "Ruby" } ] 我只需要将它作为ruby中的树，以下哈希就足够了：
{ :title => "Home", :path => [], :children => [ { :title => "About", :path => ["about"] }, { :title => "Services", :path => ["services"], :children => [ { :title => "Plans", :path => ["services", "plans"] } ]} ]}
谁能帮助我？
您只需要一个简单的辅助类和一点递归：
class Tree attr_reader :root def initialize @root = { :title => 'Home', :path => [ ], :children => [ ] } end def add(p) r_add(@root, p[:key].dup, p[:value]) self end private def r_add(h, path, value) if(path.empty?) h[:title] = value return end p = path.shift c = h[:children].find { |c| c[:path].last == p } if(!c) c = { :title => nil, :path => h[:path].dup.push(p), :children => [ ] } h[:children].push(c) end r_add(c, path, value) end end
然后：
t = a.inject(Tree.new) { |t, h| t.add(h) } h = t.root
会在h给出这个：
{:title =>"Home", :path=>[], :children=>[ {:title=>"About", :path=>["about"], :children=>[]}, {:title=>"Services", :path=>["services"], :children=>[ {:title=>"Plans", :path=>["services", "plans"], :children=>[]}, {:title=>"Training", :path=>["services", "training"], :children=>[ {:title=>"Python", :path=>["services", "training", "python"], :children=>[]}, {:title=>"Ruby", :path=>["services", "training", "ruby"], :children=>[]} ]} ]} ]}
你可以理清空:children如果他们重要的话。