我想从一个ArrayList中的数组中获得一个随机项目

Question

我正处于创建我认为本质上应该是一个简单的小程序的开始阶段。不过，我对java很陌生，所以它被证明比预期更困难。这是我所能编译的，除了最后的打印部分之外。首先，我不明白为什么不呢？其次，我需要创建一个随机生成器，从arrayList中的一个数组中随机选择一个项目。我一直在尝试这么多事情，但却无法实现。我觉得我很困惑，甚至把代码放在哪里。帮帮我！

import java.util.*; 

public class RestaurantSelector1 { 

    //public static class Tribeca4star{ 
    final static String[] italian = {"Pepolino Restaurant", "Locanda Verde", "Scalini Fedeli", "Gran Morsi", "Ecco", "Tutto il Giorno", "The Odeon", "Mamo Restaurant", "Petrarca Cucina E Vino", "Osteria Morini"}; 
    final static String[] japanese = {"Shigure", "Sushi Azabu", "Ichimura", "Brushstroke", "Takahachi Tribeca Restaurant", "Ninja New York", "DOMODOMO", "Sushi of Gari", "Hirohisa", "Blue Ribbon"}; 
    final static String[] french = {"Bouley", "Batard", "Racines", "The Odeon", "MAMO Restaurant", "La Sirene", "Le Coucou", "Balthazar", "Taureau", "L'Appart"}; 
    final static String[] american = {"American Cut Steakhouse", "Marc Forgione", "The Bennett", "Little Park", "The Odeon", "Yves", "Tribeca Grill", "Atera", "Batard", "Brandy Library"}; 
    final static String[] chinese = {"Mr. Chow", "Macao", "Khe-Yo"}; 
    final static String[] spanish = {"Tablao", "Sazon", "Despana", "Estancia 460", "Westside Coffee Shop", "Anejo Tribeca", "Terra Wine Bar", "Darlene", "Sophia's Cuban Cuisine", "Amada"}; 
    final static String[] cafe = { "Arcade Bakery", "Galerie de Cafe", "The Wooly Daily", "Cafe Belle", "Baked", "Laughing Man Coffee and Tea","La Colombe Coffee", "Kuro-Obi at Canal Street Market", "Blue Spoon Coffee", "Everyman Espresso"}; 
    final static String[] thai = {"khe-yo", "Empire", "Macao"}; 
    final static String[] indian = {"Tamarind"}; 
    final static String[] viatnamese = {"Khe-Yo", "Macao"}; 

    public static void main(String[] args){ 
     ArrayList<String[]> cuisine = new ArrayList<>(); 

     cuisine.add(italian); 
     cuisine.add(japanese); 
     cuisine.add(french); 
     cuisine.add(american); 
     cuisine.add(chinese); 
     cuisine.add(spanish); 
     cuisine.add(cafe); 
     cuisine.add(thai); 
     cuisine.add(indian); 
     cuisine.add(viatnamese); 

     System.out.println(cuisine[0,1]); 
    } 
} 

Answer 1

尝试System.out.println(cuisine.get(0)[1])

你想用ArrayList.get(int index)为了找回您的String[]对象，然后你可以通过创建一个数组内的指向字符串

Answer 2

您可以生成一个随机指数新的随机（）实例，并从nextInt,[0,cuisine.size())获得随机int的随机语言和[0,cuisine.get(rnd).length)该语言内的单词

Random rand = new Random();       //RN Generator 
int rnd  = rand.nextInt(cuisine.size());   //random lang index 
int rndWord = rand.nextInt(cuisine.get(rnd).length) //random word index 

然后，您可以使用随机索引.get(rnd)来访问您想要的String []，并获得该数组中的随机条目[rndWord]。

System.out.print(cuisine.get(rnd)[rndWord]);  //print out random word 

Answer 3

为了得到一个随机美食随机的餐厅，你可以做到以下几点：

final Random random = new Random(); 
final String[] randomCuisine = cuisine.get(random.nextInt(cuisine.size())); 
final String randomRestaurant = randomCuisine[random.nextInt(randomCuisine.length)]; 

Answer 4

如果我理解正确的话，你希望得到您的列表中随机String[]，然后得到一随机输入出String[]。你可以通过使用java.util.Random类：

public static String getRandom(List<String[]> list) { 
    Random random = new Random(); 
    int listAccess = random.nextInt(list.size()); 
    String[] s = list.get(listAccess); 
    return s[random.nextInt(s.length)]; 
} 

然后，只需将System.out.println(cuisine[0,1]);与

System.out.println(getRandom(cuisine)); 

对于你的问题，为什么你的代码不能编译取代，这是因为你必须使用.get(<index>)为List和[<index>]访问数组中的项目。

Answer 5

首先，您的导入语句不会按照书面进行编译。

import java.util.; //will not compile without class name after '.' import java.util.*; //will compile: You could also specify a specific class name in place of the *

作为生成一个随机的餐厅，你可以通过添加如下代码到你的主要方法做到这一点。我已添加了解释说明。

public static void main(String[] args) { 
    ArrayList<String[]> cuisine = new ArrayList<>(); 

    cuisine.add(italian); 
    cuisine.add(japanese); 
    cuisine.add(french); 
    cuisine.add(american); 
    cuisine.add(chinese); 
    cuisine.add(spanish); 
    cuisine.add(cafe); 
    cuisine.add(thai); 
    cuisine.add(indian); 
    cuisine.add(viatnamese); 

    Random randomArrayListIndex = new Random(); 

    int randomCuisine = randomArrayListIndex 
      .nextInt(cuisine.size()); 

    String[] randomArray = cuisine.get(randomCuisine); // get random array 
                 // from ArrayList 

    Random randomArrayIndex = new Random(); 

    String randomRestaurant = randomArray[randomArrayIndex // get random element 
                 // from array 
      .nextInt(randomArray.length)]; 
    System.out.println(randomRestaurant); 
} 

Answer 6

如何从意大利语中获得随机餐厅？除了最后一行之外，所有的东西都编译完成，我不知道如何获得一种特定类型的美食，然后是一个随机的餐厅。

ArrayList<String[]> WestVillageCuisine = new ArrayList<String[]>(); 
WestVillageCuisine.add(Expensive.WestVillage.italian); 
WestVillageCuisine.add(Expensive.WestVillage.japanese); 
WestVillageCuisine.add(Expensive.WestVillage.american); 
WestVillageCuisine.add(Expensive.WestVillage.chinese); 
WestVillageCuisine.add(Expensive.WestVillage.spanish); 
WestVillageCuisine.add(Expensive.WestVillage.cafe); 
WestVillageCuisine.add(Expensive.WestVillage.thai); 
WestVillageCuisine.add(Expensive.WestVillage.indian); 
WestVillageCuisine.add(Expensive.WestVillage.viatnamese); 
WestVillageCuisine.add(Expensive.WestVillage.greek); 

System.out.println(getRandom(WestVillageCuisine)); 
System.out.println(WestVillageCuisine.get(0).getrandom()); 

}