在C#中如何List去除重复元素？

全栈程序员-站长 • 2022年10月31日下午9:00 • 未分类 • 阅读 0

List中有两个一样的元素，想把两个都去除，用remove和removeall都不行，list中是对象，distinct好像也不太好使，还请各位帮忙解答一下。
代码片段如下：
    class Edge
    {

        public PointF start;
        public PointF end;
    }

private List<Edge> edges = new List<Edge>();

经过计算后edges中有一些edge对象，有些对象是相同的线段，但是首尾可能相反，如何判断是相同的线段，并且将两个相同的都删除？

下面这种试下

List<User> nonDuplicateList1 = users.Distinct().ToList();//通过User类的Equals实现去重

class User:IEquatable<User>//继承IEquatable接口，实现Equals方法。List就可以使用Distinct去重
{
public string name { get; set; }
string address;

   public User(string _name, string _address)
   {
       name = _name;
       address = _address;
   }

   public override string ToString()
   {
       return string.Format(“name:{0},\taddress:{1}”, name, address);
   }

   public bool Equals(User other)
   {
       return this.name == other.name;
   }
   public override int GetHashCode()
   {
       return name.GetHashCode();
   }
}
1.用GroupBy分组取第一条，实现去重，edges = edges.GroupBy(****).Select(x => x.First()).ToLust()
2.括号里是分组条件，这是一个对象分组new { a = x.start, b = x.end  }，用三元表达式解决你说的头尾小蜜蜂论坛回帖机倒装的情形

/// <summary>
/// 可枚举类型扩展;
/// </summary>
public static class EnumerableExtensions
{

/// <summary>
/// 按指定字段排除重复项;
/// https://www.cnblogs.com/niuzaihenmang/p/5620915.html
/// 示例：peopleList.DistinctBy(i => new { i.UserName }).ToList();
/// </summary>
/// <typeparam name=”TSource”></typeparam>
/// <typeparam name=”Tkey”></typeparam>
/// <param name=”source”></param>
/// <param name=”keySelector”></param>
/// <returns></returns>
public static IEnumerable<TSource> DistinctBy<TSource, Tkey>(this IEnumerable<TSource> source, Func<TSource, Tkey> keySelector)
{

HashSet<Tkey> hashSet = new HashSet<Tkey>();
foreach (TSource item in source)
{

if (hashSet.Add(keySelector(item)))
{

yield return item;
}
}
}
}