如何使用 linq 从 List 中删除两个属性的重复组合的对象？

3回答

繁星淼淼

尝试这个：  public class KeyValueClass    {        public int Age { get; set; }        public string Name { get; set; }    }    private void DoTheJob()    {        var myList = new List<KeyValueClass>        {            new KeyValueClass {Age = 21, Name = "Carl"},            new KeyValueClass {Age = 23, Name = "Vladimir"},            new KeyValueClass {Age = 25, Name = "Bob"},            new KeyValueClass {Age = 21, Name = "Olivia"},            new KeyValueClass {Age = 21, Name = "Carl"},            new KeyValueClass {Age = 30, Name = "Jacob"},            new KeyValueClass {Age = 23, Name = "Vladimir"},        };        var myDistinctList = myList.GroupBy(x => new { x.Age, x.Name })            .Select(c => c.First()).ToList();    }

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拉莫斯之舞

您可以使用 Linq 命名空间中的 Distinct() 和 IEqualityComparer：class Program{    static void Main(string[] args)    {        List<KeyValueClass> myList = new List<KeyValueClass>            {                new KeyValueClass {Age = 21, Name = "Carl"},                new KeyValueClass {Age = 23, Name = "Vladimir"},                new KeyValueClass {Age = 25, Name = "Bob"},                new KeyValueClass {Age = 21, Name = "Olivia"},                new KeyValueClass {Age = 21, Name = "Carl"},                new KeyValueClass {Age = 30, Name = "Jacob"},                new KeyValueClass {Age = 23, Name = "Vladimir"},            };        var myDistincList = myList.Distinct(new KeyValueEqualityComparer());        foreach (var item in myDistincList) { Console.WriteLine("Age: {0}, Name:{1}", item.Age, item.Name); }        Console.ReadKey();    }}public class KeyValueClass {    public int Age { get; set; }    public string Name { get; set; }}class KeyValueEqualityComparer : IEqualityComparer<KeyValueClass>{    public bool Equals(KeyValueClass x, KeyValueClass y)    {        if (x == null || y == null) return false;        if (x.Age == y.Age && x.Name.Equals(y.Name)) return true;        return false;    }    public int GetHashCode(KeyValueClass obj)    {        return (obj.Age + obj.Name).GetHashCode() + 387;    }}

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千巷猫影

只需使用 ISet 即可避免 List 的开销和性能下降：public class Person : IEquatable<Person> {    public int Age { get; private set;}    public string Name { get; private set;}    public bool override Equals(Person other){        return other.Age == Age && other.Name.Equals(Name);    }    public override int GetHashCode(){        return Age.GetHashCode() ^ Name.GetHashCode();    }}private IEnumerable<Person> MakeUniqueList(IEnumerable<Person> input){    return new HashSet<Person>(input);}为了实际删除，这将是相当缓慢的性能明智（但它会节省内存使用），使用 List.Remove(T) https://docs.microsoft.com/en-us/dotnet/api/system。 collections.generic.list-1.remove?view=netframework-4.7.2

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