在arraylist中查找重复值

2022-01-10 00:00:00 duplicates arraylist search java

我有一个 ArrayList<Car>

举例

class Car{
   String carName;
   int carType;
}

现在，我必须查找列表中是否有任何具有相同名称的汽车.最好的方法是什么?

Now, I have to find if the list has any cars having same name. What is the best way to do this?

推荐答案

创建比较器:

public class CarComparator implements Comparator<Car>
{
    public int compare(Car c1, Car c2)
    {
        return c1.carName.compareTo(c2.carName);
    }
}

现在将 ArrayList 的所有汽车添加到 SortedSet，最好是 TreeSet；如果有重复项添加到重复项列表中:

Now add all the cars of the ArrayList to a SortedSet, preferably TreeSet; if there are duplicates add to the list of duplicates:

List<Car> duplicates = new ArrayList<Car>();
Set<Car> carSet = new TreeSet<Car>(new CarComparator());
for(Car c : originalCarList)
{
    if(!carSet.add(c))
    {
        duplicates.add(c);
    }
}

最后，在您的 duplicates 中，您将拥有所有重复项.

Finally in your duplicates you will have all the duplicates.

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