C＃ - 如何从列表中找到最常见的日期

Question

I seem to have drawn a blank. I have a list of sales, retrieved like so:

List<Sales> sales = ctn.Sales.Where(s => s.DateSold >= request.FromDate && s.DateSold <= request.ToDate).ToList();

An item in the list of sales would look something like the following:

SaleID | DateSold | ProductID | ShopID

As part of a report, I would like to return to the user a simple string informing them of what day is the day that tends to sell the most.

So I think what I should do is group sales by day, get a count for each day, and then evaluate which has the highest number, however I'm not sure exactly how to do this.

Can anyone help?

Answer 1

您只需要在DateSold上进行DateSold ，然后按计数排序（它告诉您有多少项属于该组）：

salesByDay = sales.GroupBy(s => s.DateSold).OrderBy(g => g.Count());

Answer 2

If you set the exact DateTime of sold item into DateSold, you probably want to take Date part and group by it

from sale in sales
group sale by sale.DateSold.Date into grouped
orderby grouped.Count()
select new {Date = grouped.Key, Count = grouped.Count()};

Answer 3

这将为您提供销售最多的日期：

sales.GroupBy(x => x.DateSold).OrderByDescending(g => g.Count()).FirstOrDefault().Key;