Question

假设我在一些文件位置可以使用“json”对象，读取文件，评估距离并邀请朋友是任务。

require 'json'
class GeoSearch
    attr_accessor :originalLatitude, :originalLongitude, :invitationMap
    def initialize
        @originalLatitude = 28.521134
        @originalLongitude = 77.206567
        @invitationMap = Hash.new
    end
    def degreesToRadians(degrees)
      return degrees * Math::PI / 180
    end

    def findDistance(lat1, long1, lat2, long2)
        earthRadiusKm = 6371

        deltaLat = degreesToRadians(lat2 - lat1)
        deltaLon = degreesToRadians(long2 - long1)

        lat1 = degreesToRadians(lat1)
        lat2 = degreesToRadians(lat2)

        arial = Math.sin(deltaLat/2) * Math.sin(deltaLat/2) + Math.sin(deltaLon/2) * Math.sin(deltaLon/2) * Math.cos(lat1) * Math.cos(lat2)

        distance = earthRadiusKm * (2 * Math.atan2(Math.sqrt(arial), Math.sqrt(1-arial)))

        distance
    end

    def readJsonFile(fileName)
        file = File.read(fileName)
        jsonData = JSON.parse(file)
        jsonArray = jsonData["friends"]
        iteratorOnJson(jsonArray)
    end

    def iteratorOnJson(jsonArray)
        visitingFriendsIds = []
        jsonArray.each do |element|
            if(findDistance(@originalLatitude, @originalLongitude, element['latitude'], element['longitude']) <= 100)
                visitingFriendsIds << element['id']
                @invitationMap[element['id']] = element['name']
            end
        end
        visitingFriendsIds = sortElements(visitingFriendsIds, 0 ,visitingFriendsIds.length-1)
        sendInvitationtoFriends(visitingFriendsIds, jsonArray)
    end
    def sendInvitationtoFriends(visitingFriendsIds, jsonArray)
        visitingFriendsIds.each do |friendId|
            puts "id: " + friendId.to_s + "  name: " + @invitationMap[friendId]
        end
    end
    def sortElements(inputArray, low, high)
        if(low < high)
            partition = quickSort(inputArray, low, high)
            sortElements(inputArray, low, partition-1)
            sortElements(inputArray, partition+1, high)
        end
        inputArray
    end
    def quickSort(inputArray, low, high)
        pivotalPoint = inputArray[high]
        index = low
        for iterator in low..high do
            if(inputArray[iterator] <= pivotalPoint)
                swapElements(inputArray, iterator, index)
                index = index + 1
            end
        end
        index -1
    end
    def swapElements(inputArray, xIndex, yIndex)
        temp = inputArray[xIndex]
        inputArray[xIndex] = inputArray[yIndex]
        inputArray[yIndex] = temp
    end
end

GeoSearch.new.readJsonFile("/home/neha/Desktop/friends.json")#Add your fileName

如果Json对象看起来像：

# {
#   "friends": [
#   {
#   "id": "5",
#   "name": "Agueda",
#   "latitude": 28.521134,
#   "longitude": 78.206567
# },
#   {
#   "id": "2",
#   "name": "Hisako",
#   "latitude": 28.521134,
#   "longitude": 74.206567
# },
#   {
#   "id": "1",
#   "name": "Addie",
#   "latitude": 28.521134,
#   "longitude": 76.206567
# },
#   {
#   "id": "4",
#   "name": "Laure",
#   "latitude": 37.5758033375583,
#   "longitude": -122.012044535507
# },
#   {
#   "id": "3",
#   "name": "Maye",
#   "latitude": 41.77117,
#   "longitude": -87.888795
# }
# ]
# }

输出匹配好友（100公里以内）的姓名和用户ID，按用户ID（升序）排序。

有没有办法降低所写方法的复杂性。

Answer 1

您可以使用Haversine Formula计算距离，然后将该距离添加到用户的哈希值。对其进行排序并选择给定距离内的那些：

require "json"

friends=JSON.parse(DATA.read)['friends']

olat = 28.521134
olon = 77.206567

friends
     .map {|h| h['dist']=findDistance olat, olon, h["latitude"], h["longitude"]; h}
     .select {|h| h['dist']<100}
     .sort_by {|h| h['id']}
     .each {|h| puts "%s is %.2f kilometers away" % [h['name'], h['dist']]}

__END__
{
    "friends": [
    {
    "id": "5",
    "name": "Agueda",
    "latitude": 28.521134,
    "longitude": 78.206567
},
    {
    "id": "2",
    "name": "Hisako",
    "latitude": 28.521134,
    "longitude": 74.206567
},
    {
    "id": "1",
    "name": "Addie",
    "latitude": 28.521134,
    "longitude": 76.206567
},
    {
    "id": "4",
    "name": "Laure",
    "latitude": 37.5758033375583,
    "longitude": -122.012044535507
},
    {
    "id": "3",
    "name": "Maye",
    "latitude": 41.77117,
    "longitude": -87.888795
}
]
}

打印：

Addie is 97.70 kilometers away
Agueda is 97.70 kilometers away

根据朋友的经度和纬度位置，我想邀请他们

1 个答案: