java - 2つの配列リストを別の配列リストに追加する

Question

このような2つの配列リストがありますが、それらを組み合わせる方法がわかりません。Collections.copy() と addAll メソッドを試しましたが、うまくいきませんでした。それらを組み合わせて別の配列リストにする方法はありますか? 私が本当に欲しいのは、最初の arraylist に 2 番目の arraylist からのデータを格納することです。そのため、各 Point にはその中に数行が含まれます。どうすればこれを行うことができるかについて、いくつかの提案をしていただけないでしょうか。ありがとうございます。

 static ArrayList<Vertex> getPoints() {
      Scanner input = Reader(Vertex.airports);
      ArrayList<Vertex> result = new ArrayList<Vertex>();

      while(input.hasNext()){
          String point = input.nextLine();
          result.add(new Vertex(point));

      }
      input.close();
      return result;

  }

  static ArrayList<Edge> getlines(){
          Scanner input = Reader(Vertex.graph);
          ArrayList<Edge> result = new ArrayList<Edge>();

          while(input.hasNext()){
              String route = input.nextLine();
              result.add(new Edge(route));
          }
          input.close();
          return result;

      }

データは 2 つのテキスト ファイルからのもので、ファイルは次のようになります。これらは、私がここで何をしようとしているのかを示すためのほんの一部です。(インデックス、名前)

1 England
2 France

3 オランダ

(インデックス、開始、コスト、終了)

1 1 2 2
2 1 3 1
3 1 6 3
4 1 7 3
5 2 1 2
6 2 3 1
7 2 4 1
8 2 5 2
9 2 6 2
10 3 1 1
11 3 2 1
12 3 4 1
13 3 8 1
14 3 10 2

キャプテン・フォードのおかげで完成！

Answer 1

さて、私の理解では、最初のリストには空港のリストが含まれており、2番目のリストは最初のリストの空港を接続しています。

関連付けられたポイントを持つラインへの参照を保存する場合は、別のリストを含むポイントのラッパーを作成する必要があります。

class Airport {
    public Vertex point;
    public List<Edge> routes = new ArrayList<Edge>();

    public Airport(Vertex p){
        this.point = p;
    }
}

次に、リストをロードするときに、次のようにします。

static ArrayList<Airport> getAirports() {
    Scanner input = Reader(Vertex.airports);
    ArrayList<Vertex> result = new ArrayList<Vertex>();

    while(input.hasNext()){
        String point = input.nextLine();
        //  Note the small change on the next line
        result.add(new Airport(new Vertex(point)));

    }
    input.close();
    return result;
}

static ArrayList<Edge> getlines(){
    Scanner input = Reader(Vertex.graph);
    ArrayList<Edge> result = new ArrayList<Edge>();

    while(input.hasNext()){
        String route = input.nextLine();
        result.add(new Edge(route));
    }
    input.close();
    return result;

}

static void combineLists(List<Airport> airports, List<Edge> lines){
    for(Edge edge : lines){
        //  This is where we add the routes to both airports
        //  Since I don't know the structure of the edge class, I'm making a guess that you're using the integer indices that were described in the file to describe the endpoints. Note, however, that you will need to find a way to guarantee that they match the indices of the list of airports.
        airports.get(edge.p1).routes.add(edge);
        airports.get(edge.p2).routes.add(edge);
    }
}

Answer 2

私は他の答えを改善できると思います。

より完全なソリューションは次のようになります。

import java.io.File;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Scanner;

public class Airport {
    public final int id;
    public String name;
    public List<Route> outboundRoutes = new ArrayList<Route>();
    public List<Route> inboundRoutes = new ArrayList<Route>();

    public double minDistance;
    public Airport previous;

    public Airport(int id, String name){
        this.id = id;
        this.name = name;
    }

    public static class Route {
        public final int id;
        public double cost;
        public Airport departure;
        public Airport destination;

        public Route(int id, double cost, Airport departure, Airport destination){
            this.id = id;
            this.cost = cost;
            this.departure = departure;
            this.destination = destination;
        }
    }


    public static Map<Integer,Airport> readAirports(Scanner input){
        Map<Integer,Airport> airports = new HashMap<Integer,Airport>();
        while(input.hasNext()){
            //  Using a map rather than a list simplifies the process of loading 
            //  your routes, and eliminates problems that would crop up if some
            //  airports are listed out of order or removed.
            Airport port = new Airport(input.nextInt(), input.next());
            airports.put(port.id, port);
        }
        return airports;
    }


    //  Note that the list of airports must be passed when loading the routes, 
    //  but that nothing is returned -- the routes are loaded directly 
    //  into the airports.
    public static void readRoutes(Scanner input, Map<Integer,Airport> airports){

        while(input.hasNext()){
            int id = input.nextInt();
            int departureId = input.nextInt();
            int destinationId = input.nextInt();
            double cost = input.nextDouble();

            if(!(airports.containsKey(departureId) && 
                    airports.containsKey(destinationId))){
                //  You'll have to decide how to handle a situation when a route 
                //  refers to airports that don't exist
                throw new RuntimeException(
                        "Undefined airport referenced in route #" + id);
            }

            Route route = new Route(id, cost, airports.get(departureId), 
                    airports.get(destinationId));
            route.departure.outboundRoutes.add(route);
            route.destination.inboundRoutes.add(route);
        }
    }

    public static Map<Integer,Airport> loadAirports() throws FileNotFoundException {
        Scanner inAirports = new Scanner(new File("airports.txt"));
        Scanner inRoutes = new Scanner(new File("routes.txt"));
        Map<Integer,Airport> airports = readAirports(inAirports);
        readRoutes(inRoutes, airports);
        return airports;
    }

    public static void main(String[] args){
        try {
            Map<Integer,Airport> airports = loadAirports();
            for(Airport port : airports.values()){
                System.out.println(port.name + " has " + port.inboundRoutes.size() + " inbound routes and " + port.outboundRoutes.size() + " outbound routes ");
                for(Route r : port.inboundRoutes){
                    System.out.println("\tin from " + r.departure.name + " at a cost of $" + r.cost);
                }
                for(Route r : port.outboundRoutes){
                    System.out.println("\tout to " + r.destination.name + " at a cost of $" + r.cost);
                }
            }

        } catch (IOException e){
            e.printStackTrace();
        }
    }
}

シンプルでストレートな答えが必要な場合、ArrayLists でやりたいことは、ある種のネストを行わないと実行できません。

ID を持つデータを扱っているので、データが完全な順序になっていないことを心配する必要がないように、とにかく HashMap を使用することを強くお勧めします。また、メタデータ (空港名) があるため、これらのクラスを作成することは、データをモデル化するための優れた方法です。

編集: コードはすべて 1 つのファイルに収まるように変更されました。それぞれ「airports.txt」と「routes.txt」という名前のサンプルファイルを提供すると、問題なく動作するはずです。実行すると、次の出力が得られるはずです。

England(LHR) has 4 inbound routes and 4 outbound routes 
    in from France(CDG) at a cost of $2.0
    in from Holland(AMS) at a cost of $1.0
    in from Portugal(LIS) at a cost of $3.0
    in from Iceland(KEF) at a cost of $3.0
    out to France(CDG) at a cost of $2.0
    out to Holland(AMS) at a cost of $1.0
    out to Portugal(LIS) at a cost of $3.0
    out to Iceland(KEF) at a cost of $3.0
France(CDG) has 5 inbound routes and 5 outbound routes 
    in from England(LHR) at a cost of $2.0
    in from Holland(AMS) at a cost of $1.0
    in from Germany(FRA) at a cost of $1.0
    in from Italy(LIN) at a cost of $2.0
    in from Portugal(LIS) at a cost of $2.0
    out to England(LHR) at a cost of $2.0
    out to Holland(AMS) at a cost of $1.0
    out to Germany(FRA) at a cost of $1.0
    out to Italy(LIN) at a cost of $2.0
    out to Portugal(LIS) at a cost of $2.0
Holland(AMS) has 5 inbound routes and 5 outbound routes 
    in from England(LHR) at a cost of $1.0
    in from France(CDG) at a cost of $1.0
    in from Germany(FRA) at a cost of $1.0
    in from Denmark(CPH) at a cost of $1.0
    in from Finland(HEL) at a cost of $2.0
    out to England(LHR) at a cost of $1.0
    out to France(CDG) at a cost of $1.0
    out to Germany(FRA) at a cost of $1.0
    out to Denmark(CPH) at a cost of $1.0
    out to Finland(HEL) at a cost of $2.0
Germany(FRA) has 4 inbound routes and 4 outbound routes 
    in from France(CDG) at a cost of $1.0
    in from Holland(AMS) at a cost of $1.0
    in from Italy(LIN) at a cost of $1.0
    in from Sweden(ARN) at a cost of $2.0
    out to France(CDG) at a cost of $1.0
    out to Holland(AMS) at a cost of $1.0
    out to Italy(LIN) at a cost of $1.0
    out to Sweden(ARN) at a cost of $2.0
Italy(LIN) has 3 inbound routes and 3 outbound routes 
    in from France(CDG) at a cost of $2.0
    in from Germany(FRA) at a cost of $1.0
    in from Portugal(LIS) at a cost of $3.0
    out to Portugal(LIS) at a cost of $3.0
    out to France(CDG) at a cost of $2.0
    out to Germany(FRA) at a cost of $1.0
Portugal(LIS) has 3 inbound routes and 3 outbound routes 
    in from England(LHR) at a cost of $3.0
    in from France(CDG) at a cost of $2.0
    in from Italy(LIN) at a cost of $3.0
    out to England(LHR) at a cost of $3.0
    out to France(CDG) at a cost of $2.0
    out to Italy(LIN) at a cost of $3.0
Iceland(KEF) has 1 inbound routes and 1 outbound routes 
    in from England(LHR) at a cost of $3.0
    out to England(LHR) at a cost of $3.0
Denmark(CPH) has 2 inbound routes and 2 outbound routes 
    in from Holland(AMS) at a cost of $1.0
    in from Norway(OSL) at a cost of $1.0
    out to Holland(AMS) at a cost of $1.0
    out to Norway(OSL) at a cost of $1.0
Norway(OSL) has 2 inbound routes and 2 outbound routes 
    in from Denmark(CPH) at a cost of $1.0
    in from Sweden(ARN) at a cost of $1.0
    out to Denmark(CPH) at a cost of $1.0
    out to Sweden(ARN) at a cost of $1.0
Finland(HEL) has 2 inbound routes and 2 outbound routes 
    in from Holland(AMS) at a cost of $2.0
    in from Sweden(ARN) at a cost of $1.0
    out to Sweden(ARN) at a cost of $1.0
    out to Holland(AMS) at a cost of $2.0
Sweden(ARN) has 3 inbound routes and 3 outbound routes 
    in from Germany(FRA) at a cost of $2.0
    in from Norway(OSL) at a cost of $1.0
    in from Finland(HEL) at a cost of $1.0
    out to Germany(FRA) at a cost of $2.0
    out to Norway(OSL) at a cost of $1.0
    out to Finland(HEL) at a cost of $1.0