Union() 这个方法将会Union(并集)两个序列(集合)连接成一个新列表(集合) 方法定义是: public static IEnumerable<TSource> Union<TSource>(this IEnumerable<TSource> first, IEnumerable<TSource> second)
Intersect () 它将产生两个序列的交集. 方法定义是: public static IEnumerable<TSource> Intersect<TSource>(this IEnumerable<TSource> first, IEnumerable<TSource> second) public static IEnumerable<TSource> Intersect<TSource>(this IEnumerable<TSource> first, Enumerable<TSource> second,IEqualityComparer<TSource> comparer)
Except () 它是从一个集合中删除存在另一个集合中的项.两个序列产生的集合差. 英文意思是:除此之外 方法定义是: public static IEnumerable<TSource> Except<TSource>(this IEnumerable<TSource> first, IEnumerable<TSource> second) 实例代码分别如下:
using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.Data; namespace test { class Program { static void Main(string[] args) { IList<Student> oneStudents = new List<Student>(); oneStudents.Add(new Student(1,false,"小新1","徐汇")); oneStudents.Add(new Student(2,false,"小新2","闵行")); oneStudents.Add(new Student(3, false, "小新3", "嘉定")); oneStudents.Add(new Student(4, false, "小新4", "闸北")); IList<Student> twoStudents = new List<Student>(); twoStudents.Add(new Student(5, false, "小新5", "贵州")); twoStudents.Add(new Student(6, false, "小新6", "湖北")); twoStudents.Add(new Student(7, false, "小新7", "山东")); twoStudents.Add(new Student(8, false, "小新8", "西藏")); IList<Student> threeStudents = new List<Student>(); threeStudents.Add(new Student(1, false, "小新1", "徐汇")); threeStudents.Add(new Student(2, false, "小新2", "闵行")); var bingji = oneStudents.Union(twoStudents, new StudentListEquality()).ToList();//并(全)集 var jiaoji = oneStudents.Intersect(threeStudents, new StudentListEquality()).ToList();//交集 var chaji = oneStudents.Except(threeStudents, new StudentListEquality()).ToList();//差集 Console.WriteLine(); Console.WriteLine("以下是并集的结果"); bingji.ForEach(x => { Console.WriteLine(x.StudentId.ToString() + " " + x.Sex.ToString() + " " + x.Name.ToString()+" "+x.Address.ToString()); }); Console.WriteLine(); Console.WriteLine("以下是交集的结果"); jiaoji.ForEach(x => { Console.WriteLine(x.StudentId.ToString() + " " + x.Sex.ToString() + " " + x.Name.ToString() + " " + x.Address.ToString()); }); Console.WriteLine(); Console.WriteLine("以下是差集的结果"); chaji.ForEach(x => { Console.WriteLine(x.StudentId.ToString() + " " + x.Sex.ToString() + " " + x.Name.ToString() + " " + x.Address.ToString()); }); } }
以上运行的结果是: 以上的结果是重载了含有参数的IEqualityComparer<TSource> 方法,实现IEqualityComparer接口 对数据进行了重复过滤,如果不实现这个方法结果是 var bingji = oneStudents.Union(twoStudents).ToList();//并(全)集 但是对于List<T>的T是简单类型,如int string long 。。。。。是怎么样的呢?代码如下所示 IList<int> firstNumbers = new List<int>() { 1,2,3,4,5,6,7 }; IList<int> secondNumbers = new List<int>() { 8,9,10 }; IList<int> thressNumbers = new List<int>() { 1,2,3 }; var result1 = firstNumbers.Union(secondNumbers).ToList(); var result2 = firstNumbers.Intersect(thressNumbers).ToList(); var result3 = firstNumbers.Except(thressNumbers).ToList(); Console.WriteLine("以下是并集的结果"); result1.ForEach(x => Console.WriteLine(x)); Console.WriteLine(); Console.WriteLine("以下是交集的结果"); result2.ForEach(x => Console.WriteLine(x)); 结果是:
说明一下 刚回来看了下书,是差集 不是补集、 已更改! |
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