java 如何将两个列表字符串合并为一个列表
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How to combine two list string into one list
提问by Samosir
I have two list string different,
我有两个不同的列表字符串，
List<String> A= [1,2,3,4];
List<String> B= [1,2,5,6];
And I want to combine two list, in new list string in List C = new Arraylist ();
我想合并两个列表，在新的列表字符串中 List C = new Arraylist();
how to combine two list string , be like the example:
如何组合两个列表字符串，例如：
C = [1,2,3,4,5,6];
回答by Aleksander Blomsk?ld
Use Collection.addAll(), and a TreeSet, to remove duplicates and keep the result sorted.
使用Collection.addAll()和TreeSet删除重复项并保持结果排序。
Set<String> c = new TreeSet<String>(a); //create a Set with all the elements in a
c.addAll(b); //add all the elements in b
回答by ma?ek
This will get them combined
这将使它们结合起来
combined = new ArrayList<String>();
combined.addAll(A);
combined.addAll(B);
This will get the uniques
这将获得唯一性
List<String> uniques = new ArrayList<String>(new HashSet<String>(combined));
回答by Abhishek_Mishra
Do it like this :
像这样做 ：
listOne.removeAll(listTwo);
listTwo.addAll(listOne);
Collections.sort(listTwo);
You can remove the third line if you do not want it to be sorted.
如果您不想对其进行排序，可以删除第三行。
回答by Luiggi Mendoza
There are two ways to merge the results of both lists: using List#addAllor Set#addAll. The main difference between both is heavily explained here: What is the difference between Set and List?
有两种方法可以合并两个列表的结果：使用List#addAll或Set#addAll。两者之间的主要区别在这里进行了大量解释：Set 和 List 之间有什么区别？
Based on your request, you should merge both lists without repeating the items using a Set
根据您的要求，您应该合并两个列表，而不要使用 Set
List<String> lstA = new ArrayList<String>();
lstA.add("1");
lstA.add("2");
lstA.add("3");
lstA.add("4");
List<String> lstB = new ArrayList<String>();
lstA.add("1");
lstA.add("2");
lstA.add("5");
lstA.add("6");
Set<String> lstC = new LinkedHashSet<String>();
lstC.addAll(A);
lstC.addAll(B);
List<String> lstAB = new ArrayList(lstC);
回答by An Cong Tran
Declaration of A and B seems to be wrong.
A 和 B 的声明似乎是错误的。
However, given two lists A and B, to combine them into C, you can use the following code: C.addAll(A); C.addAll(B);
但是，给定两个列表 A 和 B，要将它们组合成 C，可以使用以下代码： C.addAll(A); C.addAll(B);
回答by Sandeep Pathak
List<String> A= new ArrayList<String>();
List<String> B= new ArrayList<String>();
Set<String> set = new TreeSet<String>(A);
set.addAll(B);
System.out.println(new ArrayList<String>(set));
回答by Rahul
Set<String> set = new TreeSet<String>(A); // for keeping the output sorted else you can also use java.util.HashSet
set.addAll(B);
List<String> finalList = new ArrayList<String>(set);
回答by Kiran Mohan
To get a List<String>in sorted order, use this piece of code
要获得List<String>排序顺序，请使用这段代码
String a[] = {"1","2","3","4"};
String b[] = {"1","2","5","6"};
List<String> A= Arrays.asList(a);
List<String> B= Arrays.asList(b);
Set<String> CTemp = new TreeSet<>();
CTemp.addAll(A);
CTemp.addAll(B);
List<String> C = new ArrayList<>(CTemp);
