Python Machine Learning Cookbook

Analyzing the sentiment of a sentence

Sentiment analysis is one of the most popular applications of NLP. Sentiment analysis refers to the process of determining whether a given piece of text is positive or negative. In some variations, we consider "neutral" as a third option. This technique is commonly used to discover how people feel about a particular topic. This is used to analyze sentiments of users in various forms, such as marketing campaigns, social media, e-commerce customers, and so on.

How to do it…

1. Create a new Python file, and import the following packages:

   import nltk.classify.util
   from nltk.classify import NaiveBayesClassifier
   from nltk.corpus import movie_reviews

2. Define a function to extract features:

   def extract_features(word_list): ...