I have a question about IGrouping
and the Select()
method.
Let's say I've got an IEnumerable<IGrouping<int, smth>>
in this way:
var groups = list.GroupBy(x => x.ID);
where list
is a List<smth>
.
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(...); // <- ???
}
Can anybody suggest how to get the values (List<smth>
) from an IGrouping<int, smth>
in such a context?
var groups = list.GroupBy(x => x.ID);
Can anybody suggest how to get the values (List) from an IGrouping<int, smth> in such a context?
"IGrouping<int, smth> group" is actually an IEnumerable with a key, so you either:
foreach (IGrouping<int, smth> group in groups)
{
var thisIsYourGroupKey = group.Key;
List<smth> list = group.ToList(); // or use directly group.foreach
}
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();
foreach (var v in structure)
{
var group = groups.Single(g => 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.
From definition of IGrouping :
IGrouping<out TKey, out TElement> : IEnumerable<TElement>, IEnumerable
you can just iterate through elements like this:
IEnumerable<IGrouping<int, smth>> groups = list.GroupBy(x => x.ID)
foreach(IEnumerable<smth> element in groups)
{
//do something
}
More clarified version of above answers:
IEnumerable<IGrouping<int, ClassA>> groups = list.GroupBy(x => x.PropertyIntOfClassA);
foreach (var groupingByClassA in groups)
{
int propertyIntOfClassA = groupingByClassA.Key;
//iterating through values
foreach (var classA in groupingByClassA)
{
int key = classA.PropertyIntOfClassA;
}
}
Source: Stackoverflow.com