Book Image

Python Data Analysis

By : Ivan Idris
Book Image

Python Data Analysis

By: Ivan Idris

Overview of this book

Table of Contents (22 chapters)
Python Data Analysis
Credits
About the Author
About the Reviewers
www.PacktPub.com
Preface
Key Concepts
Online Resources
Index

Sentiment analysis


Opinion mining or sentiment analysis is a hot, new research field dedicated to the automatic evaluation of opinions as expressed on social media, product review websites, or other forums. Often, we want to know whether an opinion is positive, neutral, or negative. This is, of course, a form of classification as seen in the previous section. As such, we can apply any number of classification algorithms. Another approach is to semiautomatically (with some manual editing) compose a list of words with an associated numerical sentiment score (the word "good" can have a score of 5 and the word "bad" a score of -5). If we have such a list, we can look up all words in a text document and, for example, sum up all the found sentiment scores. The number of classes can be more than three, like a five-star rating scheme.

We will apply Naive Bayes classification to the NLTK movie reviews corpus with the goal of classifying movie reviews as either positive or negative. First, we will...