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Python Data Cleaning Cookbook

You're reading from   Python Data Cleaning Cookbook Prepare your data for analysis with pandas, NumPy, Matplotlib, scikit-learn, and OpenAI

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Product type Paperback
Published in May 2024
Publisher Packt
ISBN-13 9781803239873
Length 486 pages
Edition 2nd Edition
Languages
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Author (1):
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Michael Walker Michael Walker
Author Profile Icon Michael Walker
Michael Walker
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Table of Contents (14) Chapters Close

Preface 1. Anticipating Data Cleaning Issues When Importing Tabular Data with pandas 2. Anticipating Data Cleaning Issues When Working with HTML, JSON, and Spark Data FREE CHAPTER 3. Taking the Measure of Your Data 4. Identifying Outliers in Subsets of Data 5. Using Visualizations for the Identification of Unexpected Values 6. Cleaning and Exploring Data with Series Operations 7. Identifying and Fixing Missing Values 8. Encoding, Transforming, and Scaling Features 9. Fixing Messy Data When Aggregating 10. Addressing Data Issues When Combining DataFrames 11. Tidying and Reshaping Data 12. Automate Data Cleaning with User-Defined Functions, Classes, and Pipelines 13. Index

Using random forest for imputation

Random forest is an ensemble learning method, using bootstrap aggregating, also known as bagging, to improve model accuracy. It makes predictions by repeatedly taking the mean of multiple trees, yielding progressively better estimates. We will use the MissForest algorithm in this recipe, which is an application of the random forest algorithm to missing value imputation.

MissForest starts by filling in the median or mode (for continuous or categorical variables respectively) for missing values, then uses random forest to predict values. Using this transformed dataset, with missing values replaced by initial predictions, MissForest generates new predictions, perhaps replacing the initial prediction with a better one. MissForest will typically go through at least 4 iterations of this process.

Getting ready

You will need to install the MissForest and MiceForest modules to run the code in this recipe. You can install both with pip.

How...

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