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Python Machine Learning Cookbook

You're reading from   Python Machine Learning Cookbook 100 recipes that teach you how to perform various machine learning tasks in the real world

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Product type Paperback
Published in Jun 2016
Publisher Packt
ISBN-13 9781786464477
Length 304 pages
Edition 1st Edition
Languages
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Authors (2):
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Vahid Mirjalili Vahid Mirjalili
Author Profile Icon Vahid Mirjalili
Vahid Mirjalili
Prateek Joshi Prateek Joshi
Author Profile Icon Prateek Joshi
Prateek Joshi
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Toc

Table of Contents (14) Chapters Close

Preface 1. The Realm of Supervised Learning FREE CHAPTER 2. Constructing a Classifier 3. Predictive Modeling 4. Clustering with Unsupervised Learning 5. Building Recommendation Engines 6. Analyzing Text Data 7. Speech Recognition 8. Dissecting Time Series and Sequential Data 9. Image Content Analysis 10. Biometric Face Recognition 11. Deep Neural Networks 12. Visualizing Data Index

Preprocessing data using tokenization

Tokenization is the process of dividing text into a set of meaningful pieces. These pieces are called tokens. For example, we can divide a chunk of text into words, or we can divide it into sentences. Depending on the task at hand, we can define our own conditions to divide the input text into meaningful tokens. Let's take a look at how to do this.

How to do it…

  1. Create a new Python file and add the following lines. Let's define some sample text for analysis:
    text = "Are you curious about tokenization? Let's see how it works! We need to analyze a couple of sentences with punctuations to see it in action."
  2. Let's start with sentence tokenization. NLTK provides a sentence tokenizer, so let's import this:
    # Sentence tokenization
    from nltk.tokenize import sent_tokenize
  3. Run the sentence tokenizer on the input text and extract the tokens:
    sent_tokenize_list = sent_tokenize(text)
  4. Print the list of sentences to see whether...
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