Book Image

Python Natural Language Processing Cookbook

By : Zhenya Antić
Book Image

Python Natural Language Processing Cookbook

By: Zhenya Antić

Overview of this book

Python is the most widely used language for natural language processing (NLP) thanks to its extensive tools and libraries for analyzing text and extracting computer-usable data. This book will take you through a range of techniques for text processing, from basics such as parsing the parts of speech to complex topics such as topic modeling, text classification, and visualization. Starting with an overview of NLP, the book presents recipes for dividing text into sentences, stemming and lemmatization, removing stopwords, and parts of speech tagging to help you to prepare your data. You’ll then learn ways of extracting and representing grammatical information, such as dependency parsing and anaphora resolution, discover different ways of representing the semantics using bag-of-words, TF-IDF, word embeddings, and BERT, and develop skills for text classification using keywords, SVMs, LSTMs, and other techniques. As you advance, you’ll also see how to extract information from text, implement unsupervised and supervised techniques for topic modeling, and perform topic modeling of short texts, such as tweets. Additionally, the book shows you how to develop chatbots using NLTK and Rasa and visualize text data. By the end of this NLP book, you’ll have developed the skills to use a powerful set of tools for text processing.
Table of Contents (10 chapters)

Dividing sentences into words – tokenization

In many instances, we rely on individual words when we do NLP tasks. This happens, for example, when we build semantic models of texts by relying on the semantics of individual words, or when we are looking for words with a specific part of speech. To divide text into words, we can use NLTK and spaCy.

Getting ready

For this recipe, we will be using the same text of the book The Adventures of Sherlock Holmes. You can find the whole text in the book's GitHub repository. For this recipe, we will need just the beginning of the book, which can be found in the sherlock_holmes_1.txt file.

In order to do this task, you will need the nltk package, described in the Technical requirements section.

How to do it…

  1. Import the nltk package:
    import nltk
  2. Read in the book text:
    filename = "sherlock_holmes_1.txt"
    file = open(filename, "r", encoding="utf-8")
    text = file.read()
  3. Replace...