Book Image

The Handbook of NLP with Gensim

By : Chris Kuo
Book Image

The Handbook of NLP with Gensim

By: Chris Kuo

Overview of this book

Navigating the terrain of NLP research and applying it practically can be a formidable task made easy with The Handbook of NLP with Gensim. This book demystifies NLP and equips you with hands-on strategies spanning healthcare, e-commerce, finance, and more to enable you to leverage Gensim in real-world scenarios. You’ll begin by exploring motives and techniques for extracting text information like bag-of-words, TF-IDF, and word embeddings. This book will then guide you on topic modeling using methods such as Latent Semantic Analysis (LSA) for dimensionality reduction and discovering latent semantic relationships in text data, Latent Dirichlet Allocation (LDA) for probabilistic topic modeling, and Ensemble LDA to enhance topic modeling stability and accuracy. Next, you’ll learn text summarization techniques with Word2Vec and Doc2Vec to build the modeling pipeline and optimize models using hyperparameters. As you get acquainted with practical applications in various industries, this book will inspire you to design innovative projects. Alongside topic modeling, you’ll also explore named entity handling and NER tools, modeling procedures, and tools for effective topic modeling applications. By the end of this book, you’ll have mastered the techniques essential to create applications with Gensim and integrate NLP into your business processes.
Table of Contents (24 chapters)
1
Part 1: NLP Basics
5
Part 2: Latent Semantic Analysis/Latent Semantic Indexing
9
Part 3: Word2Vec and Doc2Vec
12
Part 4: Topic Modeling with Latent Dirichlet Allocation
18
Part 5: Comparison and Applications

Using the model as an information retrieval tool

Establishing a search engine involves many significant engineering tasks, so in this section, we’ll go through the essential steps to deploy an LSI model to be part of a search engine. These steps are as follows:

  1. Load the saved objects.
  2. Preprocess the new document.
  3. Score the new document to get the latent topic scores.
  4. Calculate the similarity scores with the new document.
  5. Find documents with high similarity scores.

First, we will load the four saved objects. The objects include the dictionary list, the model, the BoW object, and the TF-IDF object.

Loading the dictionary list

Gensim has a utility function called datapath. It points to the physical location of the file. Here is the code for it:

from gensim.corpora import Dictionaryfrom gensim.test.utils import datapath
dict_file = datapath(path + “/gensim_dictionary_AGnews”)
gensim_dictionary = Dictionary.load(dict_file)
...