java - 计算字符串数组中出现的次数

Question

我正在尝试使用 Java 数组。我想要做的是计算数组字符串元素的出现次数。例如:

Clubs - 8 
Clubs - Ace 
Clubs - Jack
Hearts - 9 
Spades - 3
Hearts - 6

出现次数:

Clubs - 3
Hearts - 2
Spades - 1
Diamonds - 0

到目前为止我只编写了这个:

public class CardGame {
public static void main(String[] args){

     String[] suit = { "Clubs", "Hearts", "Diamonds", "Spades" };
     String[] deck = { "2", "3", "4", "5", "6", "7", "8", "9", "10",
                        "Jack", "Queen", "King", "Aces" };

     for( int a = 0; a < 7; a++ ){
     int i = (int) ( Math.random() * suit.length );
     int j = (int) ( Math.random() * deck.length );
         //System.out.println( "Suit " + suit[i] + " Deck " + deck[j] );
     System.out.println( suit[(int) (Math.random() * suit.length)]
             + " : " + deck[(int) (Math.random() * deck.length)]);
     }
            System.out.println();

  }
}

给我一​​些关于如何实现这一目标的想法。谢谢。

注意:这不是作业。我只是想给自己做一些关于数组的练习。

Answer 1

我相信您误解了上一个问题的答案。这个想法是在循环中使用 i 和 j 的值，而不是生成它们两次。这是一个工作示例。我没有使用 HashMap ，因为您事先知道花色及其数量，因此只需一个数组就足够了:

public class Main {
    public static void main(String[] args){

         String[] suit = { "Clubs", "Hearts", "Diamonds", "Spades" };
         String[] deck = { "2", "3", "4", "5", "6", "7", "8", "9", "10",
                            "Jack", "Queen", "King", "Aces" };
         int counts[] = new int[4];
         for( int a = 0; a < 7; a++ ){
         int i = (int) ( Math.random() * suit.length );
         int j = (int) ( Math.random() * deck.length );
             //System.out.println( "Suit " + suit[i] + " Deck " + deck[j] );
         System.out.println( suit[i] + " : " + deck[j]);
         counts[i]++;
         }
                System.out.println();
         for (int i =0;i<4;++i){
            System.out.println(suit[i] + " : " + counts[i]);
         }

      }
    }

您可以在 ideone 上看到代码.