This was a long chapter, but it was an essential step into the universal patterns of data transformations and their reflection in the F# 4.0 core library. The knowledge you acquired will support the process of idiomatic blueprinting of an arbitrary data transformation by prompting you to build your F# code around the handful of retained reference points. When you mentally dissect your task at hand into a composition of functions along the patterns covered here, the high-quality library functions are always available for you to quickly compose from them an error-free and adequately performant solution.

The next chapter will continue with the data transformation theme, looking into F# data queries and the subject of data parsing.