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R Data Mining

You're reading from   R Data Mining Implement data mining techniques through practical use cases and real-world datasets

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Product type Paperback
Published in Nov 2017
Publisher Packt
ISBN-13 9781787124462
Length 442 pages
Edition 1st Edition
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Author (1):
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Andrea Cirillo Andrea Cirillo
Author Profile Icon Andrea Cirillo
Andrea Cirillo
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Table of Contents (16) Chapters Close

Preface 1. Why to Choose R for Your Data Mining and Where to Start 2. A First Primer on Data Mining Analysing Your Bank Account Data FREE CHAPTER 3. The Data Mining Process - CRISP-DM Methodology 4. Keeping the House Clean – The Data Mining Architecture 5. How to Address a Data Mining Problem – Data Cleaning and Validation 6. Looking into Your Data Eyes – Exploratory Data Analysis 7. Our First Guess – a Linear Regression 8. A Gentle Introduction to Model Performance Evaluation 9. Don't Give up – Power up Your Regression Including Multiple Variables 10. A Different Outlook to Problems with Classification Models 11. The Final Clash – Random Forests and Ensemble Learning 12. Looking for the Culprit – Text Data Mining with R 13. Sharing Your Stories with Your Stakeholders through R Markdown 14. Epilogue
15. Dealing with Dates, Relative Paths and Functions

Looking for context in text – analyzing document n-grams

What was the main limitation of our wordclouds? As we said, the absence of context. In other words, we were looking at isolated words, which don't help us to derive any meaning apart from the limited meaning contained within the single words themselves.

This is where n-gram analysis techniques come in. These techniques basically involve tokenizing the text into groups of words rather than into single words. These groups of words are called n-grams.

We can obtain n-grams from our comments dataset by simply applying the unnest_tokens function again, but this time passing "ngrams" as value to the token argument and 2 as the value to the n argument:

comments %>% 
unnest_tokens(bigram, text, token = "ngrams", n = 2) -> bigram_comments

Since we specified 2 as the value for the...

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