6 ms·
Idle question: how did we end up with the term "inverted index" for this sort of thing? The term "index" is used because of an analogy to the index of a book.
by mjw1007 5y ago
Idle question: how did we end up with the term "inverted index" for this sort of thing?
The term "index" is used because of an analogy to the index of a book. But the so-called "inverted" index is the same way round as a book's index: you look up a word and it gives something analogous to page numbers.
- 0des 5y agoSometimes coining a new term is so attractive that people cannot resist. Imagine having that on your resume.
- pvg 5y agoIt's the opposite of 'forward index', the wikipedia page (and its references) cover some of the background. I think you're overestimating how much this terminology is based on one particular kind of book index - indexing even before electronic computers was more sophisticated than that. https://en.wikipedia.org/wiki/Inverted_index https://en.wikipedia.org/wiki/Inverted_index
- mjw1007 5y agoLooking at that, I get the impression that the story is: - someone introduced the term "inverted file" for this sort of thing (which is sensible terminology) - later people started considering these things to be a sort of database index - so they started saying "inverted index" without paying attention to what that implies as an English phrase
- pvg 5y agoI don't think that's the story, again, I think you're overemphasizing a particular kind of book index you're familiar with. Here's usage of 'direct' and 'inverted' index from 1903 that I just googled up https://books.google.com/books?id=O0AwAQAAMAAJ&pg=PA422&dq=%22%22+inverted+index+%22%22&hl=en&newbks=1&newbks_redir=0&sa=X&ved=2ahUKEwib2a-b1uDzAhXE854KHcaGB74QuwV6BAhBEAc#v=onepage&q=%22%22%20inverted%20index%20%22%22&f=false https://books.google.com/books?id=O0AwAQAAMAAJ&pg=PA422&dq=%...
- mjw1007 5y agoThat's an index of deeds, and the distinction there is that "direct" is indexed by the grantor and "inverted" is indexed by grantee. I don't think that's the same thing at all.
- pvg 5y agoI think it shows quite clearly that your theory that Information Retrieval nerds just got confused/misapplied a particular kind of book index is inaccurate and that IR nerds have been around for longer than one might think.
- pdpi 5y agoBooks (especially technical books) often have two indices: The forward index in the beginning of the book, which gives you a list of chapters/sections and where to find them; and the reverse index at the end that gives you a list of terms and gives you a list of of places to find each term.