如何将散列转换为数组、状态和首字母缩写？

Question

Array = [{:acronym => "AC", :fullname => "Acre"}, {:acronym => "AL", :fullname => "Alagoas"}, {:acronym => "AP", :fullname => "Amapá"}, {:acronym => "AM", :fullname => "Amazonas"}, {:acronym => "BA", :fullname => "Bahia"}, {:acronym => "CE", :fullname => "Ceará"}, {:acronym => "DF", :fullname => "Distrito Federal"}, {:acronym => "ES", :fullname => "Espírito Santo"}, {:acronym => "GO", :fullname => "Goiás"}, {:acronym => "MA", :fullname => "Maranhão"}, {:acronym => "MT", :fullname => "Mato Grosso"}, {:acronym => "MS", :fullname => "Mato Grosso do Sul"}, {:acronym => "MG", :fullname => "Minas Gerais"}, {:acronym => "PA", :fullname => "Pará"}, {:acronym => "PB", :fullname => "Paraíba"}, {:acronym => "PR", :fullname => "Paraná"}, {:acronym => "PE", :fullname => "Pernambuco"}, {:acronym => "PI", :fullname => "Piauí"}, {:acronym => "RR", :fullname => "Roraima"}, {:acronym => "RO", :fullname => "Rondônia"}, {:acronym => "RJ", :fullname => "Rio de Janeiro"}, {:acronym => "RN", :fullname => "Rio Grande do Norte"}, {:acronym => "RS", :fullname => "Rio Grande do Sul"}, {:acronym => "SC", :fullname => "Santa Catarina"}, {:acronym => "SP", :fullname => "São Paulo"}, {:acronym => "SE", :fullname => "Sergipe"}, {:acronym => "TO", :fullname => "Tocantins"}]

如何将一个变量与:acronym进行比较，并在其他变量中返回:fullname？我正在尝试使用Rails帮助器来完成此任务。

Answer 1

首先，您不希望将数组命名为Array，因为这是一个类名，并且它已经被占用。

你可以这样做：

def find_acronym_in(array, acronym)
    # returns nil if we don't find a match.
    array.find { |h| h[:acronym] == acronym }.try(:fetch, :fullname)
end

在你的雇员再培训局：

<%= find_acronym_in(@acronyms, 'ES') %>

这是一个简单的线性搜索，所以对于大的列表，它会很慢，但是对于短的列表，它可能不会被注意到。

如果你经常这样做，或者你有很大的列表，那么你可以在你的控制器中把你的数组重新排列成一个简单的Hash：

@acronyms_hash = @acronyms.each_with_object({ }) { |h, memo| memo[h[:acronym]] = h[:fullname] }

然后根据需要从Hash中提取内容：

<%= @acronyms_hash['ES'] %>

Answer 2

这个就行了

acronym_to_find = "SE"
Array.select { |ac| ac[:acronym] == acronym_to_find }.first[:fullname]

不过，将您的数据组织为{ => fullname}对的散列可能会更好。