Question

我有几个这样的课程：

public class TvShow
{
    public Title {get; set;}
    public List<Season> Seasons {get; set;}
}

public class Season
{
    public int SeasonNumber {get; set;}
    public List<Episode> Episodes {get; set;}
}

public class Episode
{
    public int EpisodeNumber {get; set;}
}

我有一个TvShows列表，我希望以有效的方式获得所有TvShows所有季节的总集数。显然有一些foreach解决方案：

int count = 0;
foreach (var show in tvShows) {
    foreach (var season in show.Seasons {
        foreach (var episode in season.Episodes {
            count++;
        }
    }
}

我能用linq做什么更优雅或更快？

Answer 1

嗯，您的代码相当于：

int count = tvShows.SelectMany(show => show.Seasons)
                   .SelectMany(season => season.Episodes)
                   .Count();

或者您可以使用Sum查看每个节目中的剧集数量，然后再次查看所有节目中的剧集总数：

int count = tvShows.Sum(show => show.Seasons.Sum(season => season.Episodes.Count));

或者某种混合，只是总结了所有节目中所有季节的情节数：

int count = tvShows.SelectMany(show => show.Seasons)
                   .Sum(season => season.Episodes.Count);

我希望最后一次效率最高 - 但实际上，除非你有很多节目，否则我希望所有的选择都非常快。最后也很优雅，所以这就是我想要的。

Answer 2

像

这样的东西

tvShows.SelectMany(show => show.Seasons)
       .Sum(season => season.Episodes.Count)

优雅高效的linq solultion来计算剧集的数量

2 个答案: