删除和替换 ArrayList 中的重复项

Question

如何删除 ArrayList 上的重复数字并将其替换为新数字？

我想打印不重复的数字。

这是我的代码：

import java.util.ArrayList;
import java.util.HashSet;
import java.util.Set;
import javax.swing.JOptionPane;

public class Test {
    public static void main(String[] args) {
        ArrayList<Integer> al = new ArrayList<Integer>();

        int opt = Integer.parseInt(JOptionPane.showInputDialog("How many numbers?");
        for (int i=0 ; i < opc ; i++) {
            al.add(Integer.parseInt(JOptionPane.showInputDialog("Which numbers?")));
        }

        Set<Integer> s = new HashSet<>();
        for (Integer d : al){
            if (s.add(d) == false)
                JOptionPane.showMessageDialog(null,"The number " + d + " was duplicated in position " + al.lastIndexOf(d));
                JOptionPane.showMessageDialog(null,"Replace new number"); //This is where I would like to replace the numbers if possible
            }
        JOptionPane.showMessageDialog("Your numbers without duplicates: "); //This is where it would print
        }
    }
}

Answer 1

防止在用户输入时输入重复的数字，而不是稍后检查和替换它们。

在这个地方做：

for (int i=0 ; i < opc ; i++) {
    al.add(Integer.parseInt(JOptionPane.showInputDialog("Which numbers?")));
}

检查一个号码是否已经存在，如果是，则要求另一个不重复的号码，如果是，则添加并要求下一个号码：

for (int i=0 ; i < opc ; i++) {
    int myNumber = Integer.parseInt(JOptionPane.showInputDialog("Which numbers?"));
    while( true ){
        if( ! al.contains( myNumber ))
           al.add( myNumber );
           break;
        }
        myNumber = Integer.parseInt(JOptionPane.showInputDialog("This number is a duplicate, enter another number again"));
    }
}

======== 编辑 ==================

我已经更正了这个例子。上面（上）一个中if后面缺少{：

public class MmuClass {

    public static void main(String... wwwx) {
        List<Integer> lst = Arrays.asList(4, 2, 6, -6, 9);

        ArrayList<Integer> al = new ArrayList<Integer>();

        for (int i = 0; i < 5; i++) {
            int myNumber = Integer.parseInt(JOptionPane.showInputDialog("Which numbers?"));
            while (true) {
                if (!al.contains(myNumber)) {
                    al.add(myNumber);
                    break;
                }
                myNumber = Integer.parseInt(
                        JOptionPane.showInputDialog("This number is a duplicate, enter another number again"));
            }
            al.stream().forEach(System.out::println);
        }
    }
}