Code Clinic - HL7 Lab - Book 7: Nested Splits

Some fields are still glued together after the first split. Break an HL7 line on the pipe and a name field comes back as one lump with carets inside it, because HL7 stores data inside data. This book teaches the two-level split that takes it apart, pipe first for the fields, then caret inside a single field for its components, so a surname, a given name and a middle initial each end up somewhere you can reach. Method chaining shows how to write that as one expression when it reads clearly, and how to break it up when it does not. The four HL7 delimiters are set out plainly, the pipe, the caret, the tilde and the ampersand, with what each one separates. Then the awkward reality: components that arrive empty, and the safe access pattern built on a ternary that hands back a sensible default instead of an error. All of it gets packaged into a reusable parser function, and the closing chapter handles repeats, where a tilde packs several values into one field and a nested loop walks every one of them.

Eighteen A4 pages, in full color. Written in short sentences and plain English, for readers whose first language is not English and clearer for everyone else because of it.

Every code example in this book was run before the page was printed, so the output you read is the output you get. Instant PDF download. By M.R. Sterling.