Question

任何人都可以帮我写一个linq查询，它有点混乱......基本上我有一个变量，我的代码中的numeberOfDays，本例为8

我有一张表列出了这一点。

   DayFrom  DayTo    Price
   1        3        20
   4        5        30
   6        8        40
   8        25       150

在我的情况下，我需要每天从linq返回一行8 ...

因此我最终得到了

20   (because day 1 and its from 1 to 3)
20   (because day 2 and its from 1 to 3)
20   (because day 3 and its from 1 to 3)
30   (because day 4 and its from 4 to 5)
30   (because day 5 and its from 4 to 5)
40   (because day 6 and its from 6 to 8)
40   (because day 6 and its from 6 to 8)
40   (because day 7 and its from 6 to 8)
40   (because day 8 and its from 6 to 8)

// no more records will be listed because we are on 8 and its the last day..

所以基本上我只需要在这种情况下返回一个TOTAL

20 + 20 + 20 + 30 + 30 + 40 + 40 + 40 + 40 = 280 .....

我不知道从哪里开始，如果它是在代码中，那么我可以使用一个计数器为numOfDays和一个for Next来检查Dayfrom和Dayto内的日期和价格..

我真的很感激任何反馈..

由于

Answer 1

var priceList = new[] {
    new {DayFrom = 1, DayTo = 3, PriceList = 20},
    new {DayFrom = 4, DayTo = 5, PriceList = 30},
    new {DayFrom = 6, DayTo = 8, PriceList = 40},
    new {DayFrom = 9, DayTo = 25, PriceList = 150}
};

int days = 8;

var total = (from p in priceList
         from d in Enumerable.Range(1, days)
         where p.DayFrom <= d && p.DayTo >= d
         select p.PriceList).Sum();

Console.WriteLine(total);

但是在DayTo和DayFrom中你的数据有点奇怪，所以我把它改成了9。

Answer 2

假设您有一个名为DataItem的类，其属性为DayFrom，DayTo和Price，则以下内容应该有效（请注意，我还没有对其进行过测试）：

int Total(int numberOfDays, DataItem[] items){
    var query =
        from item in items
        let daysInData = Math.Min(item.DayTo, numberOfDays) - item.DayFrom + 1
        where item.DayFrom >= numberOfDays
        select item.Price * daysInData;
    return query.Sum();
}

Answer 3

int numberOfDays = 8;

var data = new[] { new {DayFrom = 1, DayTo = 3, Price = 20},
              new {DayFrom = 4, DayTo = 5, Price = 30},
              new {DayFrom = 6, DayTo = 8, Price = 40},
              new {DayFrom = 8, DayTo = 25, Price = 150}};

int sum = data.SelectMany(x => Enumerable.Repeat(x, x.DayTo - x.DayFrom + 1))
    .Select(x => x.Price)
    .Take(numberOfDays)
    .Sum();

Console.WriteLine(sum);

帮助编写linq查询

3 个答案: