Comments by vl2 (Top 1 by date)

Probably you did not get the idea of the functional programming. It is all about transforming the immutable data structures. It is not quite correct to call it "querying". It might be a surprise for you, but you can code arbitrary complex stuff without a single destructive assignment operation (since lambda calculus is Turing-complete). To understand LINQ better you have to learn Haskell.