Question

如何删除ArrayList上的重复数字并将其替换为新数字？

我想打印数字而不重复它们。

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

防止在用户输入重复的数字时输入重复的数字，而不是在以后检查和替换它们。

在这个地方做：

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

如果一个号码已经存在则chceck，如果是，则要求另一个号码不重复，如果是，则添加它并要求下一个号码：

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==================

我已经纠正了这个例子。在上述（上一个）{之后，if之后缺少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); } } }：

UpdateItemMutation

删除并替换ArrayList中的重复项

1 个答案: