Using pivot table in linq(在 linq 中使用数据透视表)

本文介绍了在 linq 中使用数据透视表的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！

问题描述

我有以下动态列表

Crew   NameSurname  Period  Result
ABC    John DOE     Q1      54,09
ABC    John DOE     Q2      59,57
ABC    John DOE     Q3      62,11

我怎样才能在 linq 中得到这个结果.

How can I get this result with in linq.

Crew   NameSurname  Q1      Q2      Q3
ABC    John DOE     47,51   47,51   51,46

我试过这种方法，但我无法得到结果

I've tried this way but I couldn't get the result

List.GroupBy(c => c.PersonnelID)
     .Select(g => new
     {
         PersonnelID = g.Key,
         Period1 = g.Where(c => c.Period == 1).Sum(c => c.Result),
         Period2 = g.Where(c => c.Period == 2).Sum(c => c.Result),
         Period3 = g.Where(c => c.Period == 3).Sum(c => c.Result)
     });

推荐答案

你可以这样做:

var results = Data.GroupBy(l => new { l.Crew, l.NameSurname});
    .SelectMany( (key, g) => 
                 new 
                 { 
                     Crew = Key.Crew,
                     NameSurname = Key.NameSurname,  
                     groups = g 
                 });

var pivoted = new List<PivotedCrew>();

foreach(var item in results)
{
    pivoted.Add( 
        new PivotedCrew
        {
            Crew  = item.Crew,
            NameSurname = item.NameSurname,
            Q1 = item.groups.Where(x => x.Period == "Q1")
                     .FirstOrDefault().value,
            Q2 = item.groups.Where(x => x.Period == "Q2")
                     .FirstOrDefault().value,
            Q3 = item.groups.Where(x => x.Period == "Q3")
                     .FirstOrDefault().value
        });
}

但是您需要定义一个新类.比如:

But you will need to define a new class. Something like:

public class PivotedCrew
{
    public string Crew Id {get; set;}
    public string NameSurname {get; set;}
    public string Q1 {get; set;}   
    public string Q2 {get; set;}   
    public string Q3 {get; set;}   
}

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