Phantom Indexer

Phantom Indexer

The PhantomIndexer class in the provided code is an implementation of an indexer. An indexer is a program that processes data (in this case, text documents) to create an index for faster search and retrieval. The index created by the PhantomIndexer is based on the TF-IDF (Term Frequency-Inverse Document Frequency) algorithm, a common algorithm used in information retrieval.

Here's a brief overview of the PhantomIndexer class:

• The __init__ method initializes the indexer. It takes as input the name of the input file (filename) and the name of the output file (out). It also initializes several other attributes, such as the total number of documents (documents), the term frequency (tf), the inverse document frequency (idf), and the TF-IDF (tfidf).

• The calculate_tf method calculates the term frequency for each term in each document. The term frequency is the number of times a term appears in a document.

• The calculate_idf method calculates the inverse document frequency for each term. The inverse document frequency is a measure of how much information the term provides, i.e., if it's common or rare across all documents.

• The calculate_tfidf method calculates the TF-IDF for each term in each document. The TF-IDF is the product of the term frequency and the inverse document frequency. It is a measure of the importance of a term in a document in a corpus.

• The process method processes the data. It tokenizes the text, removes stop words, stems the words, and calculates the TF-IDF.

• The save method saves the TF-IDF and IDF to a file.

• The log method is used to log messages.

The PhantomIndexer class is used as follows:

1. An instance of the PhantomIndexer class is created with the input file name and the output file name.

2. The process method is called to process the data and calculate the TF-IDF.

3. The save method is called to save the TF-IDF and IDF to a file.

The output of the PhantomIndexer is a JSON file that contains the TF-IDF and IDF for each term in each document. This file can be used for fast search and retrieval of documents.