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Python Data Cleaning Cookbook

You're reading from   Python Data Cleaning Cookbook Modern techniques and Python tools to detect and remove dirty data and extract key insights

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Product type Paperback
Published in Dec 2020
Publisher Packt
ISBN-13 9781800565661
Length 436 pages
Edition 1st Edition
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Authors (2):
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Michael B Walker Michael B Walker
Author Profile Icon Michael B Walker
Michael B Walker
Michael Walker Michael Walker
Author Profile Icon Michael Walker
Michael Walker
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Toc

Table of Contents (12) Chapters Close

Preface 1. Chapter 1: Anticipating Data Cleaning Issues when Importing Tabular Data into pandas 2. Chapter 2: Anticipating Data Cleaning Issues when Importing HTML and JSON into pandas FREE CHAPTER 3. Chapter 3: Taking the Measure of Your Data 4. Chapter 4: Identifying Missing Values and Outliers in Subsets of Data 5. Chapter 5: Using Visualizations for the Identification of Unexpected Values 6. Chapter 6: Cleaning and Exploring Data with Series Operations 7. Chapter 7: Fixing Messy Data when Aggregating 8. Chapter 8: Addressing Data Issues When Combining DataFrames 9. Chapter 9: Tidying and Reshaping Data 10. Chapter 10: User-Defined Functions and Classes to Automate Data Cleaning 11. Other Books You May Enjoy

Identifying and cleaning missing data

We have already explored some strategies for identifying and cleaning missing values, particularly in Chapter 1, Anticipating Data Cleaning Issues when Importing Tabular Data into pandas. We will polish up on those skills in this recipe. We will do this by exploring a full range of strategies for handling missing data, including using DataFrame means and group means, as well as forward filling with nearby values. In the next recipe, we impute values using k-nearest neighbor.

Getting ready

We will continue working with the National Longitudinal Survey data in this recipe.

How to do it…

In this recipe, we will check key demographic and school record columns for missing values. We'll then use several strategies to impute values for missing data: assigning the overall mean for that column, assigning a group mean, and assigning the value of the nearest preceding non-missing value. Let's get started:

  1. Import pandas...
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