Linq集团按季度分组

Question

是否有可能做一个linq小组和分组几个季度,即1月1日到apr等等

Answer 1

像这样的东西

Enumerable.Range(1,12)
    .Select(o => new DateTime(DateTime.Today.Year, o, 1))
    .GroupBy(o => (o.Month - 1) / 3)

Answer 2

这是一个证明这一点的基本例子:

var dates = new[]
                    {
                        new DateTime(2011, 12, 25), 
                        new DateTime(2011, 11, 25),
                        new DateTime(2011, 5, 4),
                        new DateTime(2011, 1, 3), 
                        new DateTime(2011, 8, 9),
                        new DateTime(2011, 2, 14),
                        new DateTime(2011, 7, 4),
                        new DateTime(2011, 11, 11)
                    };

var groupedByQuarter = from date in dates
                        group date by (date.Month - 1)/3
                        into groupedDates
                        orderby groupedDates.Key
                        select groupedDates;


foreach(var quarter in groupedByQuarter)
{
    Console.WriteLine("Q: {0}, Dates: {1}", quarter.Key, string.Join(", ", quarter));
}

订单只是帮助按季度订购.您可以删除组语句后面的整个子句.

随着输出:

Q: 0, Dates: 1/3/2011 12:00:00 AM, 2/14/2011 12:00:00 AM
Q: 1, Dates: 5/4/2011 12:00:00 AM
Q: 2, Dates: 8/9/2011 12:00:00 AM, 7/4/2011 12:00:00 AM
Q: 3, Dates: 12/25/2011 12:00:00 AM, 11/25/2011 12:00:00 AM, 11/11/2011 12:00:00 AM

显然,您需要通过添加一个或者将它们翻译成相应的枚举来更正季度数字.