Book Image

Python Data Cleaning Cookbook

By : Michael Walker
Book Image

Python Data Cleaning Cookbook

By: Michael Walker

Overview of this book

Getting clean data to reveal insights is essential, as directly jumping into data analysis without proper data cleaning may lead to incorrect results. This book shows you tools and techniques that you can apply to clean and handle data with Python. You'll begin by getting familiar with the shape of data by using practices that can be deployed routinely with most data sources. Then, the book teaches you how to manipulate data to get it into a useful form. You'll also learn how to filter and summarize data to gain insights and better understand what makes sense and what does not, along with discovering how to operate on data to address the issues you've identified. Moving on, you'll perform key tasks, such as handling missing values, validating errors, removing duplicate data, monitoring high volumes of data, and handling outliers and invalid dates. Next, you'll cover recipes on using supervised learning and Naive Bayes analysis to identify unexpected values and classification errors, and generate visualizations for exploratory data analysis (EDA) to visualize unexpected values. Finally, you'll build functions and classes that you can reuse without modification when you have new data. By the end of this Python book, you'll be equipped with all the key skills that you need to clean data and diagnose problems within it.
Table of Contents (12 chapters)

Chapter 6: Cleaning and Exploring Data with Series Operations

We can view the recipes in the first few chapters of this book as, essentially, diagnostic. We imported some raw data and then generated descriptive statistics about key variables. This gave us a sense of how the values for those variables were distributed and helped us identify outliers and unexpected values. We then examined the relationships between variables to look for patterns, and deviations from those patterns, including logical inconsistencies. In short, our primary goal so far has been to figure out what is going on with our data.

The recipes in this chapter demonstrate how to use pandas methods to update series values once we have figured out what needs to be done. Ideally, we need to take the time to carefully examine our data before manipulating the values of our variables. We should have measures of central tendency, indicators of distribution shape and spread, correlations, and visualizations in front of...