Book Image

Practical Data Wrangling

By : Allan Visochek
Book Image

Practical Data Wrangling

By: Allan Visochek

Overview of this book

Around 80% of time in data analysis is spent on cleaning and preparing data for analysis. This is, however, an important task, and is a prerequisite to the rest of the data analysis workflow, including visualization, analysis and reporting. Python and R are considered a popular choice of tool for data analysis, and have packages that can be best used to manipulate different kinds of data, as per your requirements. This book will show you the different data wrangling techniques, and how you can leverage the power of Python and R packages to implement them. You’ll start by understanding the data wrangling process and get a solid foundation to work with different types of data. You’ll work with different data structures and acquire and parse data from various locations. You’ll also see how to reshape the layout of data and manipulate, summarize, and join data sets. Finally, we conclude with a quick primer on accessing and processing data from databases, conducting data exploration, and storing and retrieving data quickly using databases. The book includes practical examples on each of these points using simple and real-world data sets to give you an easier understanding. By the end of the book, you’ll have a thorough understanding of all the data wrangling concepts and how to implement them in the best possible way.
Table of Contents (16 chapters)
Title Page
Credits
About the Author
About the Reviewer
www.PacktPub.com
Customer Feedback
Preface

Variable names and contents


  • roads: The R dataframe containing the original data
  • roads.2011: The 2011 column of the roads dataframe
  • not.na: An array of logical that corresponds to the non-NA values of the 2011 column
  • roads.2011.cleaned: The 2011 column from the roads dataframe with the NA values removed
  • total.2011: The sum of the 2011 values
  • roads.num: The roads dataframe without the first column (just the numerical data)
  • roads.means: A vector containing the mean value of each row
  • roads.keep: A vector of logical that is True for rows for which the mean is less than 2000 (non-outliers)
  • roads2: The roads dataframe with outliers removed
  • roads.num2: The roads dataframe with the first column removed (just the numerical data) and the outliers removed
  • roads.means2: The vector of means with outliers removed
  • roads.num2.rowsums: The sum of the values in each row with the outliers removed (where a sum of 0 indicates that all values in the row are NA)
  • roads.keep2: A logical vector used to index the rows for which...