The second example - an information retrieval search tool

According to Wikipedia (https://en.wikipedia.org/wiki/Information_retrieval), information retrieval is:

"The activity obtaining information resources relevant to an information need from a collection of information resources"

Usually, the information resources are a collection of documents and the information needed is a set of words, which summarizes our need. To do a quick search over the document collection, we use a data structure named inverted index. It stores all the words of the document collection, and for each word, a list of the documents that contains that word. In Chapter 5, Getting Data From the Tasks - The Callable and Future Interfaces, you constructed an inverted index of a document collection constructed with the Wikipedia pages with information about movies to construct a set of 100,673 documents. We have converted each Wikipedia page into a text file. This inverted index is stored in a text file where each line contains...