How to get values from IGrouping

Question

I have a question about IGrouping and the Select   method   Let s say I ve got an IEnumerable lt IGrouping lt int  smth gt  gt  in this way   var groups   list GroupBy x   gt  x ID     where list is a List lt smth gt    And now I need to pass values of each IGrouping to another list in some way   foreach  var v in structure        v ListOfSmth   groups Select           lt -           Can anybody suggest how to get the values  List lt smth gt   from an IGrouping lt int  smth gt  in such a context

User · Answer

Assume that you have MyPayments class like

 public class Mypayment
{
    public int year { get; set; }
    public string month { get; set; }
    public string price { get; set; }
    public bool ispaid { get; set; }
}

and you have a list of MyPayments

public List<Mypayment> mypayments { get; set; }

and you want group the list by year. You can use linq like this:

List<List<Mypayment>> mypayments = (from IGrouping<int, Mypayment> item in yearGroup
                                                let mypayments1 = (from _payment in UserProjects.mypayments
                                                                   where _payment.year == item.Key
                                                                   select _payment).ToList()
                                                select mypayments1).ToList();

User · Answer

More clarified version of above answers   IEnumerable lt IGrouping lt int  ClassA gt  gt  groups   list GroupBy x   gt  x PropertyIntOfClassA    foreach  var groupingByClassA in groups        int propertyIntOfClassA   groupingByClassA Key         iterating through values     foreach  var classA in groupingByClassA                int key   classA PropertyIntOfClassA

User · Answer

From definition of IGrouping     IGrouping lt out TKey  out TElement gt    IEnumerable lt TElement gt   IEnumerable   you can just iterate through elements like this   IEnumerable lt IGrouping lt int  smth gt  gt  groups   list GroupBy x   gt  x ID  foreach IEnumerable lt smth gt  element in groups      do something

User · Answer

var groups   list GroupBy x   gt  x ID     Can anybody suggest how to get the values  List  from an IGrouping lt int  smth gt  in such a context    quot IGrouping lt int  smth gt  group quot  is actually an IEnumerable with a key  so you either   iterate on the group or use group ToList   to convert it to a List  foreach  IGrouping lt int  smth gt  group in groups       var thisIsYourGroupKey   group Key      List lt smth gt  list   group ToList           or use directly group foreach

User · Answer

foreach  var v in structure              var group   groups Single g   gt  g Key    v             v ListOfSmth   group ToList          First you need to select the desired group  Then you can use the ToList method of on the group  The IGrouping is a IEnumerable of the values

User · Answer

Since IGrouping lt TKey  TElement gt  implements IEnumerable lt TElement gt   you can use SelectMany to put all the IEnumerables back into one IEnumerable all together  List lt smth gt  list   new List lt smth gt     IEnumerable lt IGrouping lt int  smth gt  gt  groups   list GroupBy x   gt  x id   IEnumerable lt smth gt  smths   groups SelectMany group   gt  group   List lt smth gt  newList   smths ToList     Here s an example that builds runs  https   dotnetfiddle net DyuaaP Video commentary of this solution  https   youtu be 6BsU1n1KTdo

[c#] How to get values from IGrouping

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