What is the purpose of using "Select" multiple times in this LINQ query?

Question

I came across some code like this:

Dim results = From item In New List(Of Integer) From {1, 2, 3}
              Select item
              Select item

I am surprised that Select item twice is legal. It seems to behave exactly the same as if there was only one Select line. I tried converting to C# and it produces a compile error.

Is there any reason to use multiple Selects? Could this ever cause the query to behave differently?

Answer 1

the C# equivalent syntax would be :

var results = from item in new List<int> {1, 2, 3}
              select item into item
              select item;

That way you create a new scope to "chain" queries or quoted from the VB.Net documentation (see links) The Select clause introduces a new set of range variables for subsequent query clauses (you can see the into C# keyword documention or the Select VB.Net clause documentation for further information and examples)