Linq 根据多个key分组 取值demo示例

// 实现多key分组的扩展函数版本
var sums = empList
.GroupBy(x => new { x.Age, x.Sex })
.Select(group => new {
Peo = group.Key, Count = group.Count()
});
foreach (var employee in sums) {
Console.WriteLine(employee.Count + ": " + employee.Peo);
}

// 实现多key分组的lambda版本
var sums2 = from emp in empList
group emp by new { emp.Age, emp.Sex } into g
select new { Peo = g.Key, Count = g.Count() };
foreach (var employee in sums) {
Console.WriteLine(employee.Count + ": " + employee.Peo);
}