Java 如何合并两个不重复的ArrayList？
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How to merge two ArrayLists without duplicates?
提问by Sen
I have two arrayLists
我有两个数组列表
ArrayList one = {A, B, C, D, E}
ArrayList two = {B, D, F, G}
I want to have my final ArrayList which will have Allthe elements of one and the elements which are only in two and not in one.
我想要我的最终 ArrayList，它将包含一个的所有元素和只有两个而不是一个的元素。
So ArrayList final = {A, B, C, D, E, F, G}.
所以 ArrayList final = {A, B, C, D, E, F, G}。
How can I do this?
我怎样才能做到这一点？
采纳答案by John B
for (Object x : two){
if (!one.contains(x))
one.add(x);
}
assuming you don't want to use the set suggested in the comment. If you are looking for something fancier than this please clarify your question.
假设您不想使用评论中建议的集合。如果您正在寻找比这更有趣的东西，请澄清您的问题。
回答by Ankit
you can do something like this:
你可以这样做：
ArrayList<Object> result = new ArrayList<>();
result.addAll(one);
for(Object e: two){
if(!result.contains(e))
result.add(e);
}
回答by Sanjaya Liyanage
Try this kind of thing. As Setdoesn't allow duplicates you can add only the changes
试试这种东西。由于Set不允许重复，您只能添加更改
ArrayList<String> a=new ArrayList<>();
a.add("a");
a.add("b");
ArrayList<String> b=new ArrayList<>();
a.add("a");
a.add("c");
Set<String> s=new HashSet<String>();
s.addAll(a);
s.addAll(b);
a=new ArrayList<>(s);
for(String r:a){
System.out.println(r);
}
回答by Puce
Either:
任何一个：
Set<Foo> fooSet = new LinkedHashSet<>(one);
fooSet.addAll(two);
List<Foo> finalFoo = new ArrayList<>(fooSet);
or
或者
List<Foo> twoCopy = new ArrayList<>(two);
twoCopy.removeAll(one);
one.addAll(twoCopy);
