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

Building a BERTopic model

Because BERTopic is a Transformer-based model, in general, there is no need to preprocess the texts such as with stop word removal or lemmatization. Keeping the original structure of the text is important in the Transformer-based approach. Stop words are usually non-informative. If a document has a lot of stop words such as he, she, and they, the document is likely to have the non-informative topic -1, which we will see shortly. That being said, nowadays, many texts have typos and nouns can be singular or plural; the outcome of a BERTopic model on an unlemmatized corpus may have redundant keywords such as court and courts, or cup and cups. You still can apply stop word removal and lemmatization to compare the outcome.

Loading the data – no text preprocessing

I will load the same AG news data that we have been using in this book:

import pandas as pdimport numpy as np
pd.set_option('display.max_colwidth', -1)
path = “/content...