Book description
Discover how to describe your data in detail, identify data issues, and find out how to solve them using commonly used techniques and tips and tricks
Key Features
- Get well-versed with various data cleaning techniques to reveal key insights
- Manipulate data of different complexities to shape them into the right form as per your business needs
- Clean, monitor, and validate large data volumes to diagnose problems before moving on to data analysis
Book Description
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.
What you will learn
- Find out how to read and analyze data from a variety of sources
- Produce summaries of the attributes of data frames, columns, and rows
- Filter data and select columns of interest that satisfy given criteria
- Address messy data issues, including working with dates and missing values
- Improve your productivity in Python pandas by using method chaining
- Use visualizations to gain additional insights and identify potential data issues
- Enhance your ability to learn what is going on in your data
- Build user-defined functions and classes to automate data cleaning
Who this book is for
This book is for anyone looking for ways to handle messy, duplicate, and poor data using different Python tools and techniques. The book takes a recipe-based approach to help you to learn how to clean and manage data. Working knowledge of Python programming is all you need to get the most out of the book.
Table of contents
- Python Data Cleaning Cookbook
- Why subscribe?
- Contributors
- About the author
- About the reviewers
- Packt is searching for authors like you
- Preface
- Chapter 1: Anticipating Data Cleaning Issues when Importing Tabular Data into pandas
- Chapter 2: Anticipating Data Cleaning Issues when Importing HTML and JSON into pandas
- Chapter 3: Taking the Measure of Your Data
-
Chapter 4: Identifying Missing Values and Outliers in Subsets of Data
- Technical requirements
- Finding missing values
- Identifying outliers with one variable
- Identifying outliers and unexpected values in bivariate relationships
- Using subsetting to examine logical inconsistencies in variable relationships
- Using linear regression to identify data points with significant influence
- Using k-nearest neighbor to find outliers
- Using Isolation Forest to find anomalies
-
Chapter 5: Using Visualizations for the Identification of Unexpected Values
- Technical requirements
- Using histograms to examine the distribution of continuous variables
- Using boxplots to identify outliers for continuous variables
- Using grouped boxplots to uncover unexpected values in a particular group
- Examining both the distribution shape and outliers with violin plots
- Using scatter plots to view bivariate relationships
- Using line plots to examine trends in continuous variables
- Generating a heat map based on a correlation matrix
-
Chapter 6: Cleaning and Exploring Data with Series Operations
- Technical requirements
- Getting values from a pandas series
- Showing summary statistics for a pandas series
- Changing series values
- Changing series values conditionally
- Evaluating and cleaning string series data
- Working with dates
- Identifying and cleaning missing data
- Missing value imputation with K-nearest neighbor
-
Chapter 7: Fixing Messy Data when Aggregating
- Technical requirements
- Looping through data with itertuples (an anti-pattern)
- Calculating summaries by group with NumPy arrays
- Using groupby to organize data by groups
- Using more complicated aggregation functions with groupby
- Using user-defined functions and apply with groupby
- Using groupby to change the unit of analysis of a DataFrame
- Chapter 8: Addressing Data Issues When Combining DataFrames
- Chapter 9: Tidying and Reshaping Data
-
Chapter 10: User-Defined Functions and Classes to Automate Data Cleaning
- Technical requirements
- Functions for getting a first look at our data
- Functions for displaying summary statistics and frequencies
- Functions for identifying outliers and unexpected values
- Functions for aggregating or combining data
- Classes that contain the logic for updating series values
- Classes that handle non-tabular data structures
- Other Books You May Enjoy
Product information
- Title: Python Data Cleaning Cookbook
- Author(s):
- Release date: December 2020
- Publisher(s): Packt Publishing
- ISBN: 9781800565661
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