Book Image

Hands-On Data Analysis with Pandas - Second Edition

By : Stefanie Molin
5 (1)
Book Image

Hands-On Data Analysis with Pandas - Second Edition

5 (1)
By: Stefanie Molin

Overview of this book

Extracting valuable business insights is no longer a ‘nice-to-have’, but an essential skill for anyone who handles data in their enterprise. Hands-On Data Analysis with Pandas is here to help beginners and those who are migrating their skills into data science get up to speed in no time. This book will show you how to analyze your data, get started with machine learning, and work effectively with the Python libraries often used for data science, such as pandas, NumPy, matplotlib, seaborn, and scikit-learn. Using real-world datasets, you will learn how to use the pandas library to perform data wrangling to reshape, clean, and aggregate your data. Then, you will learn how to conduct exploratory data analysis by calculating summary statistics and visualizing the data to find patterns. In the concluding chapters, you will explore some applications of anomaly detection, regression, clustering, and classification using scikit-learn to make predictions based on past data. This updated edition will equip you with the skills you need to use pandas 1.x to efficiently perform various data manipulation tasks, reliably reproduce analyses, and visualize your data for effective decision making – valuable knowledge that can be applied across multiple domains.
Table of Contents (21 chapters)
Section 1: Getting Started with Pandas
Section 2: Using Pandas for Data Analysis
Section 3: Applications – Real-World Analyses Using Pandas
Section 4: Introduction to Machine Learning with Scikit-Learn
Section 5: Additional Resources

Adding and removing data

In the previous sections, we frequently selected a subset of the columns, but if columns/rows aren't useful to us, we should just get rid of them. We also frequently selected data based on the value of the mag column; however, if we had made a new column holding the Boolean values for later selection, we would have only needed to calculate the mask once. Very rarely will we get data where we neither want to add nor remove something.

Before we begin adding and removing data, it's important to understand that while most methods will return a new DataFrame object, some will be in-place and change our data. If we write a function where we pass in a dataframe and change it, it will change our original dataframe as well. Should we find ourselves in a situation where we don't want to change the original data, but rather want to return a new copy of the data that has been modified, we must be sure to copy our dataframe before making any changes: