Book Image

The Data Science Workshop - Second Edition

By : Anthony So, Thomas V. Joseph, Robert Thas John, Andrew Worsley, Dr. Samuel Asare
5 (1)
Book Image

The Data Science Workshop - Second Edition

5 (1)
By: Anthony So, Thomas V. Joseph, Robert Thas John, Andrew Worsley, Dr. Samuel Asare

Overview of this book

Where there’s data, there’s insight. With so much data being generated, there is immense scope to extract meaningful information that’ll boost business productivity and profitability. By learning to convert raw data into game-changing insights, you’ll open new career paths and opportunities. The Data Science Workshop begins by introducing different types of projects and showing you how to incorporate machine learning algorithms in them. You’ll learn to select a relevant metric and even assess the performance of your model. To tune the hyperparameters of an algorithm and improve its accuracy, you’ll get hands-on with approaches such as grid search and random search. Next, you’ll learn dimensionality reduction techniques to easily handle many variables at once, before exploring how to use model ensembling techniques and create new features to enhance model performance. In a bid to help you automatically create new features that improve your model, the book demonstrates how to use the automated feature engineering tool. You’ll also understand how to use the orchestration and scheduling workflow to deploy machine learning models in batch. By the end of this book, you’ll have the skills to start working on data science projects confidently. By the end of this book, you’ll have the skills to start working on data science projects confidently.
Table of Contents (16 chapters)
Preface
12
12. Feature Engineering

Analyzing the Content of a Categorical Variable

Now that we've got a good feel for the kind of information contained in the online retail dataset, we want to dig a little deeper into each of its columns:

import pandas as pd
file_url = 'https://github.com/PacktWorkshops/'\
           'The-Data-Science-Workshop/blob'\
           '/master/Chapter10/dataset/'\
           'Online%20Retail.xlsx?raw=true'
df = pd.read_excel(file_url)

For instance, we would like to know how many different values are contained in each of the variables by calling the nunique() method. This is particularly useful for a categorical variable with a limited number of values, such as Country:

df['Country'].nunique()

You should get the following output:

38

We can see that there are...