过滤列表。例如,我有列表如何通过列表元素
Rating rate1 = new Rating { artistID = 1, userID = 101, rating = 2 };
Rating rate2 = new Rating { artistID = 1, userID = 102, rating = 4 };
Rating rate3 = new Rating { artistID = 2, userID = 101, rating = 3 };
Rating rate4 = new Rating { artistID = 2, userID = 102, rating = 5 };
Rating rate5 = new Rating { artistID = 2, userID = 103, rating = 1 };
Rating rate6 = new Rating { artistID = 3, userID = 102, rating = 1 };
Rating rate7 = new Rating { artistID = 3, userID = 103, rating = 1 };
List<Rating> ratings = new List<Rating>(7);
ratings.Add(rate1);
ratings.Add(rate2);
ratings.Add(rate3);
ratings.Add(rate4);
ratings.Add(rate5);
ratings.Add(rate6);
ratings.Add(rate7);
而且我有第二个列表,
List<Rating> ratings2 = new List<Rating>(2);
ratings2.Add(rate1);
ratings2.Add(rate3);
现在我想用List<Rating> ratings2
过滤List<Rating> ratings
。
在这个CACE,我们用artistID
元素筛选评级名单中,其他的字,我想包括含有artistID
1和2这ratings2
上市谢谢所有的列表。
'Join'应该是'GroupJoin'来避免潜在的重复项目。 – Servy 2014-09-05 15:41:42
你不需要'group by',只需要'into'。这将执行“GroupJoin”而不是“Join”,然后是“GroupBy”。 – Servy 2014-09-05 15:54:53
感谢您指出可能与连接重复的问题,我已经完全删除了连接方法,我更喜欢HashSet。 – 2014-09-05 16:01:01