linq - 等同于 JOIN 的点符号

Question

string[] names = { "Burke", "Connor", "Frank", 
   "Albert", "George", "Harris", "David" };

peoples[] people = {
                   new peoples("Connor",20),
                   new peoples("John",22),
                   new peoples("Merry",33),
                   new peoples("Frank",65),
                   new peoples("Frank",34),
                   new peoples("George",19)
               };

var query = from n in names
            join p in people on n equals p.Name into matching
            select new { Name = n, Count = matching.Count() };

请告诉我这个查询的点符号。谢谢。

Answer 1

连接的点符号取决于它后面的内容以及您是否有“into”子句(对于组连接)。在这种情况下，它将是:

var query = names.GroupJoin(people, n => n, p => p.Name,
                   (n, matching) => new { Name = n, Count = matching.Count() });

• 如果您不使用“into”，它将使用 Join 而不是 GroupJoin
• 如果您之后除了“选择”之外还有其他任何东西，它会引入一个新的透明标识符，以有效地将“(n, matching)”保持为一个元组。