显示从 Arraylist 中删除了哪些元素 [英] Show which elements are removed from Arraylist

问题描述

我正在编写一个非常简单的世界模拟器.每一步，人们都会变老，一旦达到最大年龄，他们就会死亡.我已经设法让人们死去并将他们从 ArrayList 中删除.但是，我想显示在每个时间步骤中有哪些人死亡(因此从 ArrayList 中删除了哪些元素)，但我不知道该怎么做.这是我的代码:

I'm writing a very simple world simulator. Each time step, people get older, and once they reach a maximum age, they die. I already managed to let people die and to remove them from the ArrayList. However, I would like to show which people died during each time step (so which elements are removed from the ArrayList), but I don't know how to do it. This is my code:

for(Iterator<Person> personIterator = persons.iterator(); personIterator.hasNext();) {
    Person person = personIterator.next();
    if (person.getAge() >= Person.MAX_AGE){
        personIterator.remove();
    }
}

推荐答案

您可以将移除的元素累积到另一个集合中，然后返回/打印/不管它.例如:

You could accumulate the elements you remove to another collection, and then return/print/whatever it. E.g.:

List<Person> deaths = new LinkedList<>();
for(Iterator<Person> personIterator = persons.iterator(); personIterator.hasNext();) {
    Person person = personIterator.next();
    if (person.getAge() >= Person.MAX_AGE) {
        deaths.add(person);
        personIterator.remove();
    }
}

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