What this book covers
We can decompose this book into five general topics:
We’ll start with Acquiring Data From Sources. The first six projects will cover projects to acquire data for analytic processing from a variety of sources.
Once we have data, we often need to Inspect and Survey. The next five projects look at some ways to inspect data to make sure it’s usable, and diagnose odd problems, outliers, and exceptions.
The general analytics pipeline moves on to Cleaning, Converting, and Normalizing. There are eight projects that tackle these closely-related problems.
The useful results begin with Presenting Summaries. There’s a lot of variability here, so we’ll only present two project ideas. In many cases, you will want to provide their own, unique solutions to presenting the data they’ve gathered.
This book winds up with two small projects covering some basics of Statistical Modeling. In some organizations, this may be the start of more sophisticated data science and machine learning applications. We encourage you to continue your study of Python applications in the data science realm.
The first part has two preliminary chapters to help define what the deliverables are and what the broad sweep of the projects will include. Chapter 1, Project Zero: A Template for Other Projects is a baseline project. The functionality is a “Hello, World!” application. However, the additional infrastructure of unit tests, acceptance tests, and the use of a tool like tox or nox to execute the tests is the focus.
The next chapter, Chapter 2, Overview of the Projects, shows the general approach this book will follow. This will present the flow of data from acquisition through cleaning to analysis and reporting. This chapter decomposes the large problem of “data analytics” into a number of smaller problems that can be solved in isolation.
The sequence of chapters starting with Chapter 3, Project 1.1: Data Acquisition Base Application, builds a number of distinct data acquisition applications. This sequence starts with acquiring data from CSV files. The first variation, in Chapter 4, Data Acquisition Features: Web APIs and Scraping, looks at ways to get data from web pages.
The next two projects are combined into Chapter 5, Data Acquisition Features: SQL Database. This chapter builds an example SQL database, and then extracts data from it. The example database lets us explore enterprise database management concepts to more fully understand some of the complexities of working with relational data.
Once data has been acquired, the projects transition to data inspection. Chapter 6, Project 2.1: Data Inspection Notebook creates an initial inspection notebook. In Chapter 7, Data Inspection Features, a series of projects add features to the basic inspection notebook for different categories of data.
This topic finishes with the Chapter 8, Project 2.5: Schema and Metadata project to create a formal schema for a data source and for the acquired data. The JSON Schema standard is used because it seems to be easily adapted to enterprise data processing. This schema formalization will become part of later projects.
The third topic — cleaning — starts with Chapter 9, Project 3.1: Data Cleaning Base Application. This is the base application to clean the acquired data. This introduces the Pydantic package as a way to provide explicit data validation rules.
Chapter 10, Data Cleaning Features has a number of projects to add features to the core data cleaning application. Many of the example datasets in the previous chapters provide very clean data; this makes the chapter seem like needless over-engineering. It can help if you extract sample data and then manually corrupt it so that you have examples of invalid and valid data.
In Chapter 11, Project 3.7: Interim Data Persistence, we’ll look at saving the cleaned data for further use.
The acquire-and-clean pipeline is often packaged as a web service. In Chapter 12, Project 3.8: Integrated Data Acquisition Web Service, we’ll create a web server to offer the cleaned data for subsequent processing. This kind of web services wrapper around a long-running acquire-and-clean process presents a number of interesting design problems.
The next topic is the analysis of the data. In Chapter 13, Project 4.1: Visual Analysis Techniques we’ll look at ways to produce reports, charts, and graphs using the power of JupyterLab.
In many organizations, data analysis may lead to a formal document, or report, showing the results. This may have a large audience of stakeholders and decision-makers. In Chapter 14, Project 4.2: Creating Reports we’ll look at ways to produce elegant reports from the raw data using computations in a JupyterLab notebook.
The final topic is statistical modeling. This starts with Chapter 15, Project 5.1: Modeling Base Application to create an application that embodies lessons learned in the Inspection Notebook and Analysis Notebook projects. Sometimes we can share Python programming among these projects. In other cases, however, we can only share the lessons learned; as our understanding evolves, we often change data structures and apply other optimizations making it difficult to simply share a function or class definition.
In Chapter 16, Project 5.2: Simple Multivariate Statistics, we expand on univariate modeling to add multivariate statistics. This modeling is kept simple to emphasize foundational design and architectural details. If you’re interested in more advanced statistics, we suggest building the basic application project, getting it to work, and then adding more sophisticated modeling to an already-working baseline project.
The final chapter, Chapter 17, Next Steps, provides some pointers for more sophisticated applications. In many cases, a project evolves from exploration to monitoring and maintenance. There will be a long tail where the model continues to be confirmed and refined. In some cases, the long tail ends when a model is replaced. Seeing this long tail can help an analyst understand the value of time invested in creating robust, reliable software at each stage of their journey.
