c# 将 linq 结果分组到特定类的新列表中

Question

我需要如何编写以遍历这三个初始列表中每个列表的结果以返回单个列表。标题是分组值。

var invoiced = new List<Anonim> 
{ 
new Anonim {Category = 1, Title = "Legal", Amount = 20},
new Anonim {Category = 2, Title = "Accounting", Amount = 10}
}
var settled = new List<Anonim> {
new Anonim {Category = 1, Title = "Legal", Amount = 10}
}
var credit = new List<Anonim> {
new Anonim {Category = 1, Title = "Legal", Amount = 30},
new Anonim {Category = 2, Title = "Accounting", Amount = 20}
}

var result = new List<Result> {
new Result {Title = credit.Title, Invoiced = invoiced.Amount, Settled = settled.Amount, SumAmount = credit.Amount + settled.Amount + invoiced.Amount },
new Result {Title = credit.Title, Invoiced = invoiced.Amount, Settled = settled.Amount, SumAmount = credit.Amount + settled.Amount + invoiced.Amount }
}

public class Result
{
public string Title { get; set; }
public decimal Credit { get; set; }
public decimal Invoiced { get; set; }
public decimal Settled { get; set; }
public decimal SumAmount { get; set; }
}
public class Anonim { 
public int Category { get; set; }
public string Title { get; set; }
public decimal Amount { get; set; }
}

总金额是每个项目的发票、已结算、贷方的总和

Answer 1

目前还不清楚您想要发生什么，但假设您想按Title属性分组，这里有一种方法。首先，将每个列表投影到Result类中，确保为每个列表设置相关属性，将它们合并到一个大列表中，然后将它们分组以获得总计：

var groupedResults = invoiced.Select(i => new Result
{
Title = i.Title,
Invoiced = i.Amount
}).Union(settled.Select(i => new Result
{
Title = i.Title,
Settled = i.Amount
})).Union(credit.Select(i => new Result
{
Title = i.Title,
Credit = i.Amount
}));
var result = groupedResults
.GroupBy(r => r.Title)
.Select(g => new Result
{
Title = g.Key,
Invoiced = g.Sum(r => r.Invoiced),
Settled = g.Sum(r => r.Settled),
Credit = g.Sum(r => r.Credit),
SumAmount = g.Sum(r => r.Invoiced+r.Settled+r.Credit)
});

Answer 2

如果我理解正确，这是您想要的，但是由于大量集合遍历，这是低效的。也许@DavidG解决方案的性能会更高。

var groupedSum = invoiced.Union(settled).Union(credit).GroupBy(g => g.Title).Select(g => new Result
{ 
Title = g.Key,
Credit = credit.Where(c => c.Title == g.Key).Sum(c => c.Amount),
Settled = settled.Where(c => c.Title == g.Key).Sum(c => c.Amount),
Invoiced = invoiced.Where(c => c.Title == g.Key).Sum(c => c.Amount),
SumAmount = g.Sum(i => i.Amount)
});

Answer 3

这是我能找到的最简单的：

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace ConsoleApplication73
{
class Program
{
static void Main(string[] args)
{
List<Anonim> invoiced = new List<Anonim> 
{ 
new Anonim {Category = 1, Title = "Legal", Amount = 20},
new Anonim {Category = 2, Title = "Accounting", Amount = 10}
};
List<Anonim> settled = new List<Anonim> {
new Anonim {Category = 1, Title = "Legal", Amount = 10}
};
List<Anonim> credit = new List<Anonim> {
new Anonim {Category = 1, Title = "Legal", Amount = 30},
new Anonim {Category = 2, Title = "Accounting", Amount = 20}
};
List<Result> results = new List<Result>();

List<string> titles = invoiced.Select(x => x.Title).ToList();
titles.AddRange(settled.Select(x => x.Title).ToList());
titles.AddRange(credit.Select(x => x.Title).ToList();
titles = titles.Distinct().ToList();

foreach(string title in titles)
{
Result newResult = new Result();
results.Add(new Result);
newResult.Title = title;
newResult.Credit = credit.Where(x => x.Title == title).Sum(x => x.Amount);
newResult.Invoiced = invoiced.Where(x => x.Title == title).Sum(x => x.Amount);
newResult.Settled = settled.Where(x => x.Title == title).Sum(x => x.Amount);
newResult.SumAmount = newResult.Credit + newResult.Invoiced + newResult.Settled;
}
}
}
public class Result
{
public string Title { get; set; }
public decimal Credit { get; set; }
public decimal Invoiced { get; set; }
public decimal Settled { get; set; }
public decimal SumAmount { get; set; }
}
public class Anonim
{
public int Category { get; set; }
public string Title { get; set; }
public decimal Amount { get; set; }
}
}

Answer 4

var invoiced = new List<Anonim> 
{ 
new Anonim {Category = 1, Title = "Legal", Amount = 20},
new Anonim {Category = 2, Title = "Accounting", Amount = 10}
};
var settled = new List<Anonim> {
new Anonim {Category = 1, Title = "Legal", Amount = 10}
};
List<Anonim> credit = new List<Anonim> {
new Anonim {Category = 1, Title = "Legal", Amount = 30},
new Anonim {Category = 2, Title = "Accounting", Amount = 20}
};
List<Result> x = new List<Result>();
x.AddRange(invoiced.Select(y => new Result { Title = y.Title, Invoiced = y.Amount }));
x.AddRange(settled.Select(y => new Result { Title = y.Title, Invoiced = y.Amount }));
x.AddRange(credit.Select(y => new Result { Title = y.Title, Invoiced = y.Amount }));

var FinalList = x.GroupBy(a => a.Title(.选择(Fn => 新结果 { 标题 =Fn.Key， 已开票 = Fn.Sum(a => a.已开票(，'' 已结算 = Fn.Sum(a => a.已结算(， 信用 = Fn.Sum(a => a.信用(， 总金额 = Fn.总和(a => a.发票 + a.已结算 + a.贷方( });