Получение хэш-ключ, значение которого массив содержит заданную строку

Question

У меня есть следующий код:

country_code = infer_country # will grab a user's two character country code 
region = 'us' # united states by default 
region_map = { 
     "au" => ["au"], # australia 
     "al" => ["al", "ba", "bg", "hr", "md", "me", "mk", "ro", "si"], # bulgaria and the balkans 
     "cn" => ["cn"], # china 
     "ee" => ["ee", "lt", "lv"], # estonia and the baltics 
     "fi" => ["fi"], # finland 
     "at" => ["at", "ch", "de"], # germany, austria, switzerland 
     "cy" => ["cy", "gr", "mt"], # greece, cyprus, malta 
     "hk" => ["hk"], # hong_kong 
     "id" => ["id"], # indonesia 
     "it" => ["it"], # italy 
     "jp" => ["jp"], # japan 
     "kp" => ["kp", "kr"], # korea 
     "ar" => ["ar", "bl", "bo", "br", "bz", "cl", "co", "cr", "cu", "do", "ec", "gf", "gp", "gt", "hn", 
       "ht", "mf", "mq", "mx", "ni", "pa", "pe", "pr", "py", "sv", "uy", "ve"], # latin america including brazil 
     "my" => ["my"], # malaysia 
     "af" => ["af", "eg", "iq", "ir", "sa", "ye", "sy", "il", "jo", "ps", "lb", "om", "kw", "qa", "bh"], # middle east 
     "nl" => ["nl"], # netherlands 
     "no" => ["no"], # norway 
     "pl" => ["pl"], # poland 
     "pt" => ["pt"], # portugal 
     "ph" => ["ph"], # philippines 
     "ru" => ["ru"], # russia 
     "rs" => ["rs"], # serbia 
     "sg" => ["sg"], # singapore 
     "za" => ["za"], # south africa 
     "bn" => ["bn", "bu", "kh", "la", "tl", "vn"], # south east asia 
     "es" => ["es"], # spain 
     "tw" => ["tw"], # taiwan 
     "th" => ["th"], # thailand 
     "tr" => ["tr"], # turkey 
     "gb" => ["gb" ] # united kingdom 
    }.invert 
# version 0.0 
region_map.each do |key, value| 
    if key.include? country_code 
    region = value 
    break 
    end 
end 

puts region 

Если country_code является "gb", то "gb" должен быть распечатан. Если country_code находится на юго-востоке Азии, скажем, это "vn", то "bn" следует распечатать.

Как я могу изящно решить эту проблему? При необходимости я могу реструктурировать хэш.

Answer 1

def find_region(country_code) 
    pair = @region_map.find{|k, v| v.include?(country_code)} 
    pair && pair.first 
end 

find_region('gb') # => "gb" 
find_region('bz') # => "ar" 
find_region('lv') # => "ee" 
find_region('ls') # => nil 

Answer 2

region_map = Hash.new("us").merge(
    "au" => "au", 
    "al" => "al", 
    "ba" => "al", 
    "bg" => "al", 
    "hr" => "al", 
    "md" => "al", 
    "me" => "al", 
    "mk" => "al", 
    "ro" => "al", 
    "si" => "al", 
    "al" => "al", 
    "cn" => "cn", 
    ... 
) 

region_map["non existing code"] # => "us" 
region_map[nil] # => "us" 
region_map["au"] # => "au" 
region_map["ba"] # => "al" 
region_map["cn"] # => "cn" 

или

def region_map code 
    case code 
    when "au" 
    "au" 
    when "al", "ba", "bg", "hr", "md", "me", "mk", "ro", "si" 
    "al" 
    when "cn" 
    "cn" 
    when "ee", "lt", "lv" 
    "ee" 
    ... 
    else 
    "us" 
    end 
end 

region_map("non existing code") # => "us" 
region_map(nil) # => "us" 
region_map("au") # => "au" 
region_map("ba") # => "al" 
region_map("cn") # => "cn" 

Answer 3

def find_region(country_code) 
    @region_map.each {|k,v| return k if v.include? country_code} 
    nil 
end