群和总结选择许多C＃？

Question

我有一个传入的数组，每行的计数和一个字符串表示一个或多个按键的下划线分隔。

每个我想组和求和总其中如果键出现在一行中，共有5，通过下划线分割的每个项目具有它们的总增加5

我被键只是不知道如何做到这一点的LINQ表示...

class Owl 
    { 
     public int SpeciesCount { get; set; } 
     public string BandIdentifier { get; set; } 
    } 

public class GoOwl 
{ 
    public GoOwl(Owl[] owls) 
    { 
     //just making a list of test data to illustrate what would be coming in on the array 
     var owlList = new List<Owl>(); 
     owlList.Add(new Owl { SpeciesCount = 2, BandIdentifier = "OWL1" }); 
     owlList.Add(new Owl { SpeciesCount = 1, BandIdentifier = "OWL1_OWL2_OWL3" }); 
     owlList.Add(new Owl { SpeciesCount = 2, BandIdentifier = "OWL3" }); 
     owlList.Add(new Owl { SpeciesCount = 5, BandIdentifier = "OWL2_OWL3" }); 

     //i'd ideally like to have something like a row for each band identifier split on underscore plus a total species count.. 
     //where you'd sum the species count for each underscored item and group 


    } 
} 

以下将所需的输出为单猫头鹰对象

["OWL1", 3] 
["OWL2", 6] 
["OWL3", 8] 

我仍然不是很让小号electMany ..

干杯

Answer 1

用流利的sytnax：

//For each 'owlItem' in the owlList, select an anonymous objects for each key in the BandIdentifier string, keeping track of the associated SpeciesCount 
//Since each call to Split('_').Select(...) produces an IEnumerable of those anonymous objects, use SelectMany to flatten the IEnumerable to IEnumerables 
owlList.SelectMany(owlItem => owlItem.BandIdentifier.Split('_') 
       .Select(key => new { OwlKey = key, owlItem.SpeciesCount })) 
      //Group together those anonymous objects if they share the same key 
      .GroupBy(info => info.OwlKey) 
      //For each of the groups, sum together all the associated SpeciesCounts 
      .Select(group => new { group.Key, SpeciesCount = group.Sum(info => info.SpeciesCount) })' 

Answer 2

好像你想要这个：

var results = 
    owlList.SelectMany(owl => owl.BandIdentifier.Split('_'), 
         (owl, band) => new { owl, band }) 
      .GroupBy(x => x.band) 
      .Select(group => new Owl 
        { 
         BandIdentifier = group.Key 
         SpeciesCount = group.Sum(g => g.SpeciesCount) 
        }); 

或者在查询语法：

var results = 
    from owl in owlList 
    from band in owl.BandIdentifier.Split('_') 
    group owl by band into group 
    select new Owl { 
     BandIdentifier = group.Key 
     SpeciesCount = group.Sum(g => g.SpeciesCount) 
    }; 

Answer 3

var owlResults = owlList 
      //Use SelectMany to split and select all species 
      //and have a select to get the count along with the species 
      .SelectMany(O => O.BandIdentifier.Split('_') 
       .Select(owl => new { Species = owl, Count = O.SpeciesCount })) 
      //Here you can group and get the sum 
      .GroupBy(O => O.Species) 
      .Select(owl => new { Species = owl.Key, Count = owl.Sum(o => o.Count) });