Question

如何删除链接列表中的对象。我有一个带有studentId和studentName的班级帐户。我在列表中输入了对象，但是当我尝试删除对象时我不知道该怎么做。因为每次从列表中间删除元素时，它都会被组织起来，这意味着索引会改变。因此，如何获取studentId属性并删除链表中的对象。

示例：

LinkedList: Account{studentId = 1, studentName = nome1} = index = 0 , 
LinkedList: Account{studentId = 2, studentName = nome2} = index = 1 , 
LinkedList: Account{studentId = 3, studentName = nome3} = index = 2.

我想要的是让用户插入他要删除的studentId，我可以执行一个代码来搜索和删除该对象。

public Account{
    private int studentID;
    private String StudentName;
}

public static void main(String[] args){

    int accountNumber;

    LinkedList<Account> linkedAccount = new LinkedList<>();
    Account obj1;

    System.out.println("Type the acc number: ");
    accountNumber = in.nextInt();
    obj1 = linkedAccount.remove(accountNumber);
    System.out.println("The " + obj1 + " has been deleted");
}

每次我从中间删除对象时，它都会更改linkedList的索引。重新排列。所以我不知道该怎么办，您能帮我吗？

Answer 1

如果您不需要保留对要删除的对象的引用，则可以

linkedAccount.removeIf(acc -> acc.getStudentID() == accountNumber);

如果要保留对要删除的元素的引用，可以

for (Account acc : linkedAccount) {
    if (acc.getStudentID() == accountNumber) {
        obj1 = acc;
        linkedAccount.remove(acc);
        break;
    }
}

// OR

for (int i = 0; i < linkedAccount.size(); i++) {
    if (linkedAccount.get(i).getStudentID() == accountNumber) {
        obj1 = linkedAccount.remove(i);
        break;
    }
}

请注意，在大多数情况下，基本上ArrayList就足够了When to use LinkedList over ArrayList in Java?

Answer 2

当前，您使用accountNumber作为不正确的索引，而是遍历列表并找到对象的索引，然后删除：

for (int i = 0; i < linkedAccount.size(); i++) {
     if (linkedAccount.get(i).getStudentID() == accountNumber) {
         obj1 = linkedAccount.remove(i);
         break;
     }
}

此外，为什么要使用LinkedList而不是ArrayList？后者几乎总是有利的。

Answer 3

我认为最好的选择是按StudentID在列表中搜索该帐户，然后将其删除。

public Account{
    private int studentID;
    private String StudentName;

    public int getStudentID() {
       return this.studentID;
    }
}

public static void main(String[] args){

   int accountNumber;

   LinkedList<Account> linkedAccount = new LinkedList<>();
   Account obj1;

   System.out.println("Type the acc number: ");
   accountNumber = in.nextInt();
   for (int i = 0; i < linkedAccount.size(); i++) {
      if (accountNumber == linkedAccount.get(i).getStudentID()) {
         System.out.println("The student " + linkedAccount.get(i).getStudentID() + " has been deleted");
         linkedAccount.remove(i);
         break; // This is to exit for loop, but if you want to delete every instance in the list with this ID you can skip this break
      }
   }
}

如何在链接列表中按属性删除对象？

3 个答案: