Like mentioned, groupby,etc all operate on functions, (map/reduce/filter/etc) are just named differently (select/aggregate/where/etc). What makes people love L

Like mentioned, groupby,etc all operate on functions, (map/reduce/filter/etc) are just named differently (select/aggregate/where/etc). What makes people love Linq is that it handles 2 different cases (identical syntax but different backing objects). 1: The in-memory variant does things lazily, select/aggregate/where produce enumeration objects so after the chain you add ToArray, ToList, ToDictionary,etc and the final object is built lazily with most of the chain executed on as few objects as possible (thus if you have an effective Where at the start, the rest of the pipeline will do very little work and very few allocations). 2: The compiler also helps the libraries by providing syntax-tree's, thus database Linq providers just translates the Linq to SQL and sends it off to the server, letting the server do the heavy lifting _with indexes_ so that we can query tables of arbitrary sizes with regular C# Linq syntax very quickly without most of it never going over the network.