为什么我不能正确地从此阵列中删除一个项目？

Question

删除项目时，将从阵列中删除它，然后打印一条消息，指出该项目已被删除。

我知道，由于数组未排序，因此删除项目的最简单方法是将当前的最后一个项目移到其位置，然后减少项目数。

我做错了什么？ 我该如何解决？

public static int removeBall(String[] hookPotentialArray, String[] nameBallArray, int[] ballWeightArray, int count) {
    Scanner keyboard = new Scanner(System.in);
    System.out.println("Please enter the name of the ball you would like to remove: ");
    String name = keyboard.nextLine();
    boolean ballRemoval = false;
    for (int i = 0; i < count; i++) {
        if (name.compareToIgnoreCase(nameBallArray[i]) == 0 && !ballRemoval) {

            nameBallArray[i] = nameBallArray[count - 1];
            ballWeightArray[i] = ballWeightArray[count - 1];
            hookPotentialArray[i] = hookPotentialArray[count - 1];

            ballRemoval = true;
            count--;

            System.out.println("The ball you selected to be removed "
                    + "has been removed.");
            System.out.println("");
        }
    }
    return count;
}

Answer 1

最好创建一个Ball类来存储名称，权重和潜在值，并使用List来存储Ball对象。 List也有自己的添加和删除项目的方法。

Answer 2

（1）您应使用break退出搜索

（2）删除最后一项时，应添加特殊检查

（3）请记住，java数组实际上不会收缩，因此需要始终保持计数正确并在使用中

如下所示：

package tests.StackOverflow;

public class q27159679 {

    public static void main(String[] args) {

        String[] hookPotentialArray = {"alpha", "beta", "gamma", "delta"}; 

        String[] nameBallArray = {"A", "B", "C", "D"}; 

        int[] ballWeightArray = {11, 12, 13, 14};

        int count = hookPotentialArray.length;

        printBalls(nameBallArray, count);

        count = removeBall(hookPotentialArray, nameBallArray, ballWeightArray, count, "B");

        count = removeBall(hookPotentialArray, nameBallArray, ballWeightArray, count, "D");


    }


    public static int removeBall(String[] hookPotentialArray, String[] nameBallArray, int[] ballWeightArray, int count, String name) {

        System.out.println("Removing ball " + name);

        for (int i = 0; i < count; i++) {
            if (name.compareToIgnoreCase(nameBallArray[i]) == 0 ) {

                if( i < count - 1) {
                    nameBallArray[i] = nameBallArray[count - 1];
                    ballWeightArray[i] = ballWeightArray[count - 1];
                    hookPotentialArray[i] = hookPotentialArray[count - 1];
                }

                count--;

                System.out.println("The ball you selected to be removed "
                        + "has been removed.");
                printBalls(nameBallArray, count);
                System.out.println("");

                break;
            }
        }
        return count;
    }

    public static void printBalls(String[] nameBallArray, int count) {
        System.out.print("The remaining balls: ");
        for(int i=0; i<count; ++i) {
            System.out.print(nameBallArray[i] + " ");
        }
        System.out.println("");
    }



}