selecting distinct elements from two lists using LINQ?

Question

List<int> lst1 = new List<int>{1,2,3,5,2};
List<int> lst2 = new List<int>{4,5,6,1,6};
List<int> lst3 = new List<int>();

Expected Output: lst3={1,2,3,4,5,6}

Can anyone help me with the LINQ code to select distinct elements from two lists ?

Thank you

Answer 1

使用Union()方法生成两个列表的Set Union，返回包含两个列表中存在的所有项的新列表：

lst3 = list1.Union(lst2).OrderBy(p=>p).ToList();

Answer 2

Basically, you can do

lst1.AddRange(lst2);
List<int> lst3  = lst1.Distinct().ToList();

Answer 3

Another approach (I think the most effcient one [amortized]):

var hashSet = new HashSet<int>(lst1);
foreach (var item in lst2) 
{
    hashSet.Add(item);
}

var lst3 = hashSet.ToList();

LINQ:

var lst3 = lst1.Union(lst2).ToList();

Answer 4

A basic approach

        List<int> lst3 = new List<int>();
        foreach (int x in lst1)
            if (!lst3.Contains(x))
                lst3.Add(x);
        foreach (int x in lst2)
            if (!lst3.Contains(x))
                lst3.Add(x);

Answer 5

您可以使用UNION并从结果集中获取DISTINCT值

lst3 = lst1.Union(lst2).Distinct().ToList();