如何创建带有字符串的二维数组？

Question

我想格式化一个名为 events 的二维数组，当 while 循环完成时，它看起来像这样：

incidents {{1500, xxxxxx, jan, 2010},{2000, xxxxxx, feb, 2000},{1000, xxxxxx, sep, 2016}}

我可以使用类似incidents[0,3]的方式访问数组：给出第一个数组的第三个值，即 jan。

import java.util.Scanner;

public class Incident {
    public static String main(String[] args) {
        String[] incident;       // Want to make this array a 2d array       
        Scanner myObj = new Scanner(System.in);
        int choice = 1;
        while(choice!=0) {
            System.out.println("Enter value, postcode, month and year:");
            String value = myObj.nextLine();
            String postcode = myObj.nextLine();
            String month = myObj.nextLine();
            String year = myObj.nextLine();
            incident = new String[]{value, postcode, month, year};
            System.out.println("Enter 0 if you would like to exit entering incidents. Any other key if not.");
            choice = myObj.nextInt();
        }

        return null;
    }

}

Answer 1

考虑使用ArrayList ：

import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import java.util.Scanner;

public class Incident {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        List<String[]> incidentsList = new ArrayList<>();
        int i = 0;
        while (true) {
            System.out.printf("Enter incident %d details:%n", ++i);
            System.out.print("Enter value: ");
            String value = scanner.nextLine();
            System.out.print("Enter postcode: ");
            String postcode = scanner.nextLine();
            System.out.print("Enter month: ");
            String month = scanner.nextLine();
            System.out.print("Enter year: ");
            String year = scanner.nextLine();
            String[] incident = new String[]{value, postcode, month, year};
            incidentsList.add(incident);
            System.out.println("Enter 0 if you would like to exit entering incidents. " +
                    "Any other key if not.");
            String choice = scanner.nextLine();
            if (choice.equals("0")) {
                break;
            }
        }
        System.out.printf("%nYou entered the following incidents:%n");
        for (String[] incident : incidentsList) {
            System.out.println(Arrays.toString(incident));
        }
        System.out.printf("%nincidentsList.get(0)[3] = %s%n", incidentsList.get(0)[3]);
    }
}

示例用法：

Enter incident 1 details:
Enter value: 1500
Enter postcode: xxxxx
Enter month: jan
Enter year: 2010
Enter 0 if you would like to exit entering incidents. Any other key if not.

Enter incident 2 details:
Enter value: 2000
Enter postcode: xxxxx
Enter month: feb
Enter year: 2000
Enter 0 if you would like to exit entering incidents. Any other key if not.
a
Enter incident 3 details:
Enter value: 1000
Enter postcode: xxxxx
Enter month: sep
Enter year: 2016
Enter 0 if you would like to exit entering incidents. Any other key if not.
0

You entered the following incidents:
[1500, xxxxx, jan, 2010]
[2000, xxxxx, feb, 2000]
[1000, xxxxx, sep, 2016]

incidentsList.get(0)[3] = jan