.NET 4.0 Generics Beginner's Guide

Time for action – set to default if there is more than one matching elements

Follow the given steps:

1. Copy the following as a query to LINQPad:

   int[] numbers = { 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11};
   int n = numbers.SingleOrDefault(c => c % 2 == 0 && c % 6 == 0);
   n.Dump();

2. Run the query and you will see the following output:
   

Output is 6 because numbers has 2 and 6 and only 6 matches the predicate passed as the argument to the SingleOrDefault() method call.

The following diagram explains how the SingleOrDefault() method behaves in two different situations:

So SingleOrDefault() is just Single() with the default value attached. So, if you think usage of Single() ...