learn-co-students / dsc-json-xml-intro-houston-ds-111819

JSON and XML - Introduction

Introduction

In this section, you'll learn about two additional data types: JSON and XML. Both are extensively used on the web, XML being the older of the two formats, and JSON being the new standard data format for the web. Additionally, you'll also learn about recursive python functions.

Working with JSON and XML

A substantial part of the job of a professional data scientist is to find and access data. You've spent a bunch of time looking at how to pull information from relational databases, but there is lots of information you might need to work with that is either not in a relational database, or that is not exposed to you via a relational database.

For example, you might work with a third party website that has a lot of geographical data (perhaps points of interest near state highways). Within their company, they may well store the data within a relational database, but you might have to access it using an API (an Application Programming Interface - a way your computer can talk to their computer to go get some information!). Over the next couple of sections, we'll be looking at accessing data through APIs and enough HTML and CSS to get started with web scraping (downloading information automatically from websites). In this section, you'll look at a couple of key data storage formats that you may well come across when retrieving data from other web applications or from inside your company.

JSON and XML

You'll start off this section with a brief introduction to both JSON and XML so you know what they look like and their relative strengths and weaknesses. You'll then get some hands-on practice loading and parsing data from both JSON and XML formatted files into Python.

JSON Schemas

Once you've learned how to import data that has been stored in the JSON format, you'll look at JSON schemas - a way to describe the expected structure of a given JSON file.

Recursive Functions

Next, you'll take a bit of a sidestep to introduce recursive functions. A recursive function is one that calls itself - perhaps many times. Recursive functions can be used to write incredibly terse and powerful solutions to certain types of problems. They take quite a while to get used to, but once you learn how to use them you'll be surprised at how often they can help you to solve a problem that would otherwise be much more difficult (or even impossible) to solve. You’ll be introduced to them now because recursive functions can be a very powerful tool for parsing JSON or XML documents that could have very deeply embedded information (e.g. a person has worked at many companies, each company has many addresses and each address has much staff, each of which has an email address).

Exploring JSON Schemas

Finally, you'll get a lot more practice working with JSON schemas, exploring unknown schemas, accessing and manipulating data inside a JSON file and then converting JSON to alternate data formats. This lab will be a great chance for you to practice your Python programming skills, work with recursive functions and get comfortable with importing and transforming JSON data - something you may well have to do on a regular basis as a professional data scientist.

Summary

Whether it’s from an API or a NoSQL store, it's quite possible that some of the data you find yourself working with will be stored using either XML or JSON. In this section, you'll build the confidence to be able to import and transform such data.