从数组中删除最低值

Question

说我有这个哈希数组：

[{:title => "Frankenstein", :edition => 1}, {:title => "Frankenstein", :edition => 2}, {:title => "Dracula", :edition => 1}, {:title => "Dracula", :edition => 2}, {:title => "Dracula", :edition => 3}]

是否有一种优雅的方式可以剥离所有旧版本的数组，只保留最高版本（最新版本）？

[{:title => "Frankenstein", :edition => 2}, {:title => "Dracula", :edition => 3}]

Answer 1

可以这样做：

array.group_by{|h| h[:title]}.values.map{|a| a.max_by{|h| h[:edition]}}
# => [{:title=>"Frankenstein", :edition=>2}, {:title=>"Dracula", :edition=>3}]

Answer 2

使用以下代码

，您可以获得任何特定类型版本的最高价值

array = [{:title => "Frankenstein", :edition => 1}, {:title => "Frankenstein", :edition => 2}, {:title => "Dracula", :edition => 1}, {:title => "Dracula", :edition => 2}, {:title => "Dracula", :edition => 3}]

array.select{|x| x[:title] == "Dracula"}.max_by{|x| x[:edition]}