Book Image

Data Analysis with R, Second Edition - Second Edition

Book Image

Data Analysis with R, Second Edition - Second Edition

Overview of this book

Frequently the tool of choice for academics, R has spread deep into the private sector and can be found in the production pipelines at some of the most advanced and successful enterprises. The power and domain-specificity of R allows the user to express complex analytics easily, quickly, and succinctly. Starting with the basics of R and statistical reasoning, this book dives into advanced predictive analytics, showing how to apply those techniques to real-world data though with real-world examples. Packed with engaging problems and exercises, this book begins with a review of R and its syntax with packages like Rcpp, ggplot2, and dplyr. From there, get to grips with the fundamentals of applied statistics and build on this knowledge to perform sophisticated and powerful analytics. Solve the difficulties relating to performing data analysis in practice and find solutions to working with messy data, large data, communicating results, and facilitating reproducibility. This book is engineered to be an invaluable resource through many stages of anyone’s career as a data analyst.
Table of Contents (24 chapters)
Title Page
Copyright and Credits
Packt Upsell
Contributors
Preface
Index

Regular expressions


Suppose you find that there are commas separating every third digit of the numbers in a numeric column. How would you remove them? Or suppose you needed to strip a currency symbol from values in columns that hold monetary values so that you can compute with them as numbers. These, and vastly more complicated text transformations, can be performed using a most powerful tool, regular expressions.

What are regular expressions?

Regular expressions (or regexes, as it is commonly abbreviated) is a formal grammar for describing patterns in text/strings. In general purpose programming languages, it is often used for things like verifying user input, but it is most often used in the context of statistical programming to transform the textual representation of raw data. Regular expressions are—at once—the plural form of a single regular expression, a powerful tool, an idea, and a language for describing patterns in text.

You might ask yourself: How do I work with this? You might first...