Job Ready Python

Lesson 20Processing JSON Files

This is the third lesson on working with files using Python. In the previous two lessons, we learned about working with basic text files and with CSV files. In this lesson, the focus shifts to working with JSON files, which can represent unstructured datasets and with key:value pairs. Like with the other file formats, we can use Python scripts to read JSON files, add (or append) content to an existing file, and create new files.

LEARNING OBJECTIVES

By the end of this lesson, you will be able to:

• Open, read, and display JSON files.
• Append content to an existing JSON file.
• Replace data in an existing JSON file with new data.

NOTE The data files for this book are in the JobReadyPython.zip file, which you can download from www.wiley.com/go/jobreadypython. Some of the examples use the data file prize.json, which is included in the zipped data files folder provided for this lesson. This is a large file, so the examples in this lesson are truncated to save space. Run the code on your own computer to see the full output.

PROCESSING JSON FILES

Python has a built-in package called JavaScript Object Notation (JSON), which can be used to work with JSON data. The abbreviation is pronounced like the name “Jason.” We use JSON to store unstructured datasets in a format that allows us to transfer data from one system to another, in the same way we use CSV to transfer structured datasets.

We say that JSON is unstructured because we can create records ...