[英]Shifting a specific matching key-value pair from Ruby hash
我有一个 Ruby hash:
@tags = { "project_status" => { "title" => "Project status" },
"milestones" => { "title" => "Milestones"},
"lessons" => { "title" => "Lessons"},
"tasks" => { "title" => "Tasks"} }
我想shift
这个 hash 中移出特定的键值对。例如,如果我对"milestones"
标签感兴趣,那么shift
hash 上会给我:
=> ["milestones", {"title"=>"Milestones"}]
这正是我想要的。
除了我不知道如何 select 一个特定的键值对。
我可以写一些东西来遍历 hash 直到我找到匹配的键然后调用shift
,但我假设有一个更干净的“Ruby 方式”来做到这一点:)
delete
可能是你要找的。 它从 hash 中删除相应的键(而shift
从数组中删除项目)
tags = { "project_status" => { "title" => "Project status" },
"milestones" => { "title" => "Milestones"},
"lessons" => { "title" => "Lessons"},
"tasks" => { "title" => "Tasks"} }
def shift hash, key
[key, hash.delete(key)] # removes key/value pair
# [key, hash[key]] # leaves key/value pair
end
shift tags, 'milestones' # => ["milestones", {"title"=>"Milestones"}]
tags # => {"project_status"=>{"title"=>"Project status"}, "lessons"=>{"title"=>"Lessons"}, "tasks"=>{"title"=>"Tasks"}}
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