Question

class AgeClass
{
    string[] Names {get;set;}
    int Age {get;set;}
}

...

IEnumerable<AgeClass> myList = ...; // a few instances of AgeClass

now i want to get (out of myList) a

IEnumerable<KeyValuePair<string,int>> 

with a Pair of Name and Age. How to do this easily?

Answer 1

myList.SelectMany(
     x=> x.Names.Select(
          z => new KeyValuePair<string,int>(z,x.Age)));

Note that you must be aware that linq is creating a query – each time you enumerate this collection new one will be created based on current state of myList. To remove this effect simply add .ToList() to the end of this line.