Based on the introduction Lucene

Consider the following collection of documents

Construction of a collection of documents inverted index

ID documents	Document Content	Document word list
1	Artificial intelligence has become the focus of Internet Conference	Artificial | intelligent | to be | focus | Internet | Assembly
2	Google launched the open source artificial intelligence system tools	Google | launch | Open Source | artificial | intelligent | System | Tools
3	Future of the Internet in Artificial Intelligence	Internet | the | future | in | artificial | Smart
4	Google open-source machine tool drills	Google | open-source | machine | Exercise | Tools

For the content of the document, first word, began inverted index

Inverted index construction process

Lexical item	Document frequency	Inverted record form
Artificial	3	1，2，3
intelligent	3	1，2，3
become	1	1
the Internet	2	1，3
General Assembly	1	1
focus	1	1
Google	2	2，4
roll out	1	2
Open source	2	2，4
system	1	2
tool	2	2，4
of	1	3
future	1	3
in	1	3
machine	1	4
Learn	1	4