Book Image

Hands-On Data Preprocessing in Python

By : Roy Jafari
5 (2)
Book Image

Hands-On Data Preprocessing in Python

5 (2)
By: Roy Jafari

Overview of this book

Hands-On Data Preprocessing is a primer on the best data cleaning and preprocessing techniques, written by an expert who’s developed college-level courses on data preprocessing and related subjects. With this book, you’ll be equipped with the optimum data preprocessing techniques from multiple perspectives, ensuring that you get the best possible insights from your data. You'll learn about different technical and analytical aspects of data preprocessing – data collection, data cleaning, data integration, data reduction, and data transformation – and get to grips with implementing them using the open source Python programming environment. The hands-on examples and easy-to-follow chapters will help you gain a comprehensive articulation of data preprocessing, its whys and hows, and identify opportunities where data analytics could lead to more effective decision making. As you progress through the chapters, you’ll also understand the role of data management systems and technologies for effective analytics and how to use APIs to pull data. By the end of this Python data preprocessing book, you'll be able to use Python to read, manipulate, and analyze data; perform data cleaning, integration, reduction, and transformation techniques, and handle outliers or missing values to effectively prepare data for analytic tools.
Table of Contents (24 chapters)
1
Part 1:Technical Needs
6
Part 2: Analytic Goals
11
Part 3: The Preprocessing
18
Part 4: Case Studies

Log transformation

We should use this data transformation when an attribute experiences exponential growth and decline across the population of our data objects. When you draw a box plot of these attributes, you expect to see fliers, but those are not mistaken records, nor are they unnatural outliers. Those significantly larger or smaller values come naturally from the environment.

Attributes with exponential growth or decline may be problematic for data visualization and clustering analysis; furthermore, they can be problematic for some prediction and classification algorithms where the method uses the distance between the data objects, such as KNN, or where the method drives its performance based on collective performance metrics, such as linear regression.

These attributes may sound very hard to deal with, but there is a very easy fix for them – log transformation. In short, instead of using the attribute, you calculate the logarithms of all of the values and use them...