在 ruby​​ 中对哈希进行排序

Question

sorter.sort_by{|name, user_id| user_id} 不工作。即使哈希映射排序器已排序，它也会打印未排序的哈希。

我已在哈希映射中附加了名称和user_id 所需的条件：

require 'json'
class Numeric
    def to_rad
      self * Math::PI / 180
    end
  end

  def distance( lat2,  lon2)
     lat1=12.9611159
     lon1=77.6362214
     dLat = (lat2-lat1).to_rad;
     dLon = (lon2-lon1).to_rad;
     a = Math.sin(dLat/2) * Math.sin(dLat/2) +
         Math.cos(lat1.to_rad) * Math.cos(lat2.to_rad) *
         Math.sin(dLon/2) * Math.sin(dLon/2);
     c = 2 * Math.atan2(Math.sqrt(a), Math.sqrt(1-a));
     d = 6371 * c;
    return d
  end

file= File.read('customers.json')
data_hash= JSON.parse(  file)
 sorter = Hash.new

data_hash["customers"].each do |user|
  latitude=user["latitude"].to_f
  longitude=user["longitude"].to_f
  $count=0
 if (distance(latitude,longitude).to_f < 100.00)
        name = user["name"]
        user_id=user["user_id"]

        sorter[name]=user_id
        # print name," ",user_id
        # print "\n"

  end
    # 

 end
 sorter.sort_by{|name, user_id| user_id}    

 print sorter 

Answer 1

sort_by 返回排序后的数组，它不对数组进行原地排序。

2.3.0 :001 > x = %w( aa aaa a )
 => ["aa", "aaa", "a"]
2.3.0 :003 > x.sort_by { |w| w.size }
 => ["a", "aa", "aaa"]
2.3.0 :004 > x
 => ["aa", "aaa", "a"]

这意味着你要么写

print sorter.sort_by{|name, user_id| user_id} 

或者你必须将结果重新分配给sorter

sorter = sorter.sort_by{|name, user_id| user_id} 
print sorter