Question

从一系列哈希：

response = [
  {"label"=>"cat", "name"=>"kitty", "id"=>189955},
  {"label" => "dog", "name"=>"rex", "id" => 550081}
]

有没有办法写出类似的东西：

response.name.kitty

检索包含此值的哈希：

{"label"=>"cat", "name"=>"kitty", "id"=>189955}

Answer 1

你可以这样做 -

response.select{|x| x["name"] == "kitty"}.first

Answer 2

使用Proc

response = [{"label"=>"cat", "name"=>"kitty", "id"=>189955},
            {"label" => "dog", "name"=>"rex", "id" => 550081}]
finder = Proc.new {|k, v| response.find {|r| r[k] == v} }

然后

finder.call('name', 'rex')
# => {"label"=>"dog", "name"=>"rex", "id"=>550081} 
finder.call('label', 'cat')
# => {"label"=>"cat", "name"=>"kitty", "id"=>189955}

Answer 3

如果您使用 Rails - 只需使用 .pluck

array_of_hashes = [
  { name: "Kate", city: "Minsk", country: "Belarus", id: 1 },
  { name: "Mike", city: "New York", country: "USA", id: 2 },
  { name: "Aleh", city: "Warsaw", country: "Poland", id: 3},
]


>> array_of_hashes.pluck(:name)
>>
>> [ "Kate", "Mike", "Aleh" ]

Answer 4

如果需要，您还可以传递多个条件：

response = [
  {"label"=>"cat", "name"=>"kitty", "id"=>189955},
  {"label"=>"cat", "name"=>"kitty", "id"=>189956},
  {"label"=>"cat", "name"=>"kitty", "id"=>189957},
  {"label"=>"cat", "name"=>"meow", "id"=>189957},
  {"label" => "dog", "name"=>"rex", "id" => 550081},
  {"label" => "dog", "name"=>"tommy", "id" => 550082},
  {"label" => "dog", "name"=>"rex", "id" => 550083}
]

> response.select{|h| h["label"] == "cat" && h["name"] == "kitty" && h["id"] == 189955}
=> [{"label"=>"cat", "name"=>"kitty", "id"=>189955}] # returns array of selected hashes

> response.find{|h| h["label"] == "cat" && h["name"] == "kitty" && h["id"] == 189955}
=> {"label"=>"cat", "name"=>"kitty", "id"=>189955} # returns first match element

从散列数组中选择一个值

4 个答案: