的Linq：总计组按月

Question

我有一个简单的业务对象：

Crime 
    Date 
    PersonsInvolved 

我需要每月PersonsInvolved的总清单。数据为1年，所以不需要考虑年份。

Jan 5 
Feb 3 
Mar 5 

等

这是如何在LINQ的做，如果我有一个在内存中收集这样的：

List<Crime>() crimes; 

Answer 1

 

var q = from i in crimes 
    group i by i.Date.ToString("MMM") into grp 
    select new {Month = grp.Key, Count = grp.Sum(i => i.Persons)}; 
 

Answer 2

List<Crime>() crimes = ... 
var crimesPerMonth = crimes.GroupBy(x => x.Date.Month); 

Answer 3

crimes.GroupBy(c => c.Date.Month).Select(g => new { Month = g.Key, Count = g.Count() });