Natural Language Processing

This recipe will show you how to classify text into general topics. We will use supervised machine learning model called Support Vector Machines (SVM) and the 20 Newsgroups subject matter data set as the topic classifier. This recipe is based on Jinman Zhang's Cookbook.

This recipe with show you how to prepare Voronoi diagrams, one way of showing relationships between words in a text and a search term. In order to do this, we will employ the use of word embeddings. These represent individual words in a text as real-valued vectors in a confined vector space. This recipe is based on Kynan Ly's cookbook as seen on this notebook.

Multidimensional Scaling (MDS) is a method to convert sets of document terms into a data frame that can then be visualized. The distances expressed in the visualization show how similar, or dissimilar, the contents of one text are to another. This recipe deals with several advanced text analysis concepts and methods. Links are provided to additional information on these terms.

Panda Data frame: https://pandas.pydata.org/

TF-IDF: https://en.wikipedia.org/wiki/Tf%E2%80%93idf

Principal Component Analysis (PCA) is a method to convert sets of document terms into a data frame that can then be visualized. The distances expressed in the visualization show how similar, or dissimilar, the contents of one text are to another. PCA tries to identify a smaller number of uncorrelated variables, called "principal components" from the dataset. The goal is to explain the maximum amount of variance with the fewest number of principal components.  This recipe deals with several advanced text analysis concepts and methods.

Similar to finding People and Characters, finding locations in text is a common exploratory technique. This recipe shows how to extract places, countries, cities from a text. We will use Named-Entity Recognition (NER) module of NLKT library to achieve this. This recipe is based on Jinman Zhang's cookbook.

In this recipe we use 3 ebooks to show how topic analysis can identify the different topics each text represents. We will use Latent Dirichlet Allocation (LDA) approach which is the most common modelling method to discover topics. We can then spice it up with an interactive visualization of the discovered themes. This recipe is based on Zhang Jinman's notebook found on TAPoR.

NB: Any number of texts can be used, we choose 3 for this recipe.

Word frequencies and counts are text analysis methods that return results about the words in a text or set of texts. Counts return the amount of times a word is used in the text, whereas frequencies give a sense of how often a word is used in comparison to others in the text.

Tokenization is the process of splitting a sentence or a chunk of text into its constituent parts. These “tokens” may be the letters, punctuation, words, or sentences. They could even be a combination of all these elements. This recipe was adapted from a Python Notebook written by Kynan Lee.

Stemming and Lemmatization are text analysis methods that return the root word of derivative forms of the word. This is done by removing the suffixes of words (stemming) or by comparing the derivative words to a predetermined vocabulary of their root forms (lemmatization). This recipe was adapted from a Python Notebook written by Kynan Lee.

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