从ArrayLists中删除重复项 [英] Remove duplicates from ArrayLists

问题描述

我有一个自定义对象的ArrayList。我想删除重复的条目。

I have an ArrayList of custom objects. I want to remove duplicate entries.

对象有三个字段： title，subtitle 和 id 。如果一个字幕多次出现，我只需要第一个带有那个副标题的项目（忽略带有该副标题的剩余对象）。

The objects have three fields: title, subtitle, and id. If a subtitle occurs multiple times, I only need the first item with thats subtitle (ignore the remaining object with that subtitle).

推荐答案

您可以使用自定义Comparator将ArrayList的内容放入TreeSet中，如果两个字幕是相同。
之后，您可以转换列表中的Set并使列表没有重复。
这是Object的一个例子，当然你应该使用正确的类和逻辑。

You can put the content of the ArrayList in a TreeSet using a custom Comparator which should return 0 if the two subtitles are the same. After that you can convert the Set in a List and have the List without "duplicates". Here is an example for Object, of course you should use the correct class and logic.

public void removeDuplicates(List<Object> l) {
    // ... the list is already populated
    Set<Object> s = new TreeSet<Object>(new Comparator<Object>() {

        @Override
        public int compare(Object o1, Object o2) {
            // ... compare the two object according to your requirements
            return 0;
        }
    });
            s.addAll(l);
    List<Object> res = Arrays.asList(s.toArray());
}

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