C# LINQ-带条件的分组列表
读过了吗 但我想进一步了解 假设一个列表包含22个ITEM01,每个ITEM01的数量为10,以及2个ITEM02,每个ITEM02的数量为50C# LINQ-带条件的分组列表,c#,linq,group-by,C#,Linq,Group By,读过了吗 但我想进一步了解 假设一个列表包含22个ITEM01,每个ITEM01的数量为10,以及2个ITEM02,每个ITEM02的数量为50 # |ITEM |QUANTITY ================== 1 |ITEM01| 10 2 |ITEM01| 10 3 |ITEM01| 10 . . . . . . 22|ITEM01| 10 23|ITEM02| 50 24|ITEM02| 50 如何获得如下结果:(如果计数>10,转到下一行) 谢
# |ITEM |QUANTITY
==================
1 |ITEM01| 10
2 |ITEM01| 10
3 |ITEM01| 10
. . .
. . .
22|ITEM01| 10
23|ITEM02| 50
24|ITEM02| 50
如何获得如下结果:(如果计数>10,转到下一行)
谢谢你的帮助 检查代码中的注释以查看发生了什么以及查询的实际功能
// input generation
var input = Enumerable.Range(1, 22)
.Select(x => new { ID = x, Item = "ITEM01", Quantity = 10 })
.Concat(Enumerable.Range(23, 2)
.Select(x => new { ID = x, Item = "ITEM02", Quantity = 50 }));
// query you're asking for
var output =
input.GroupBy(x => x.Item) // group by Item first
.Select(g => g.Select((v, i) => new { v, i }) // select indexes within group
.GroupBy(x => x.i / 10) // group items from group by index / 10
.Select(g2 => g2.Select(x => x.v)) // skip the indexes as we don't need them anymore
.SelectMany(g2 => // flatten second grouping results and apply Sum logic
g2.Count() == 10
// if there are 10 items in group return only one item with Quantity sum
? new[] { new { Item = g.Key, Quantity = g2.Sum(x => x.Quantity) } }
// if less than 10 items in group return the items as they are
: g2.Select(x => new { Item = g.Key, Quantity = x.Quantity })))
.SelectMany(g => g); // flatten all results
你为什么需要这个?
// input generation
var input = Enumerable.Range(1, 22)
.Select(x => new { ID = x, Item = "ITEM01", Quantity = 10 })
.Concat(Enumerable.Range(23, 2)
.Select(x => new { ID = x, Item = "ITEM02", Quantity = 50 }));
// query you're asking for
var output =
input.GroupBy(x => x.Item) // group by Item first
.Select(g => g.Select((v, i) => new { v, i }) // select indexes within group
.GroupBy(x => x.i / 10) // group items from group by index / 10
.Select(g2 => g2.Select(x => x.v)) // skip the indexes as we don't need them anymore
.SelectMany(g2 => // flatten second grouping results and apply Sum logic
g2.Count() == 10
// if there are 10 items in group return only one item with Quantity sum
? new[] { new { Item = g.Key, Quantity = g2.Sum(x => x.Quantity) } }
// if less than 10 items in group return the items as they are
: g2.Select(x => new { Item = g.Key, Quantity = x.Quantity })))
.SelectMany(g => g); // flatten all results