Inverted Index - Example

Example

Given the texts "it is what it is", "what is it" and "it is a banana", we have the following inverted file index (where the integers in the set notation brackets refer to the subscripts of the text symbols, etc.):

"a": {2} "banana": {2} "is": {0, 1, 2} "it": {0, 1, 2} "what": {0, 1}

A term search for the terms "what", "is" and "it" would give the set .

With the same texts, we get the following full inverted index, where the pairs are document numbers and local word numbers. Like the document numbers, local word numbers also begin with zero. So, "banana": {(2, 3)} means the word "banana" is in the third document, and it is the fourth word in that document (position 3).

"a": {(2, 2)} "banana": {(2, 3)} "is": {(0, 1), (0, 4), (1, 1), (2, 1)} "it": {(0, 0), (0, 3), (1, 2), (2, 0)} "what": {(0, 2), (1, 0)}

If we run a phrase search for "what is it" we get hits for all the words in both document 0 and 1. But the terms occur consecutively only in document 1.