c# - RavenDB Map Reduce Transform 折叠一个不同的字符串列表

Question

我的问题很短，我坚持下去。我有一系列文件，例如：

{
...,
"Type": [
    "Type1",
    "Type2",
    "Type3",
    "Type4"
  ],
...
}

而且我认为我需要创建一个 map/reduce 索引来将这些值分组到一个字符串列表中，例如，如果我有这两个文档：

{
...,
"Type": [
    "Type1",
    "Type3"
  ],
...
}

{
...
"Type": [
    "Type2",
    "Type3",
    "Type4"
  ],
...
}

我需要一个包含所有不同值的列表的结果，例如 {"Type1","Type2","Type3","Type4"}

我不知道该怎么做，我尝试了几种方法，但没有成功。

我忘了说，我有大量的数据，像现在1500多个文档

public class ProjectTypeIndex : AbstractIndexCreationTask<Project, ProjectTypeIndex.ReduceResult>
{
    public class ReduceResult
    {
        public string ProjectType { get; set; }
    }

    public ProjectTypeIndex()
    {
        Map = projects => from project in projects
                                   select new
                                       {
                                           project.Type
                                       };
        Reduce = results => from result in results
                            group result by result.Type into g 
                            select new
                                {
                                    ProjectType = g.Key
                                };
    }
}

Answer 1

大家好，我找到了一个解决方案，但我不知道是否是最好的方法，因为我仍然没有字符串列表，只有结果，我解决了它通过 foreach 填充字符串列表，这是索引创建。如果有人可以检查代码，我将非常感激。

public class ProjectTypeIndex : AbstractIndexCreationTask<Project, ProjectTypeIndex.ReduceResult>
{
    public class ReduceResult
    {
        public string ProjectType { get; set; }
    }

    public ProjectTypeIndex()
    {
        Map = projects => from project in projects
                                   from type in project.Type
                                   select new
                                       {
                                           ProjectType = type
                                       };

        Reduce = results => from result in results
                            group result by result.ProjectType into g
                            select new
                                {
                                    ProjectType = g.Key
                                };
    }
}