Book Image

NLTK Essentials

By : Nitin Hardeniya
Book Image

NLTK Essentials

By: Nitin Hardeniya

Overview of this book

<p>Natural Language Processing (NLP) is the field of artificial intelligence and computational linguistics that deals with the interactions between computers and human languages. With the instances of human-computer interaction increasing, it’s becoming imperative for computers to comprehend all major natural languages. Natural Language Toolkit (NLTK) is one such powerful and robust tool.</p> <p>You start with an introduction to get the gist of how to build systems around NLP. We then move on to explore data science-related tasks, following which you will learn how to create a customized tokenizer and parser from scratch. Throughout, we delve into the essential concepts of NLP while gaining practical insights into various open source tools and libraries available in Python for NLP. You will then learn how to analyze social media sites to discover trending topics and perform sentiment analysis. Finally, you will see tools which will help you deal with large scale text.</p> <p>By the end of this book, you will be confident about NLP and data science concepts and know how to apply them in your day-to-day work.</p>
Table of Contents (17 chapters)
NLTK Essentials
Credits
About the Author
About the Reviewers
www.PacktPub.com
Preface
Index

Summary


In this chapter we talked about all the data wrangling/munging in the context of text. We went through some of the most common data sources, and how to parse them with Python packages. We talked about tokenization in depth, from a very basic string method to a custom regular expression based tokenizer.

We talked about stemming and lemmatization, and the various types of stemmers that can be used, as well as the pros and cons of each of them. We also discussed the stop word removal process, why it's important, when to remove stop words, and when it's not needed. We also briefly touched upon removing rare words and why it's important in text cleansing—both stop word and rare word removal are essentially removing outliers from the frequency distribution. We also referred to spell correction. There is no limit to what you can do with text wrangling and text cleansing. Every text corpus has new challenges, and a new kind of noise that needs to be removed. You will get to learn over time...