--- title: "Python JSON: Easily Work With Dictionaries, Files, and Custom Objects" date: "2022-05-03" categories: - "learn-to-code" - "python-for-beginners-posts" coverImage: "JSON-3.jpg" --- # Python JSON: Easily Work With Dictionaries, Files, and Custom Objects JSON (JavaScript Object Notation) is perhaps the most popular data-interchange format. Python has a built-in JSON package that lets you conveniently and quickly encode and decode JSON to and from Python dictionaries, which share a similar key/value structure but are much easier to manipulate in Python. This tutorial will show you how to work with Python JSON and dictionaries to encode and decode JSON. In addition to serializing dictionaries to and from JSON strings, the Python json module also includes methods to write and read Python dictionaries as Python files easily. These methods are straightforward to use once you've seen how to serialize dictionaries to and from JSON strings. In addition to dictionaries, however, you may have times when you want to read a custom Python object from JSON or serialize it back. In this case, there are at least two approaches we can take. There's a little more involved than the dictionary case, but it's nevertheless not difficult. Let's get started! ## An Overview of the Python JSON Module The Python JSON module is included with the Python standard library and gives you everything you need to work with Python JSON data. Before we begin a detailed discussion of this module, let's briefly summarize the functions and classes exported by this JSON library and some non-library approaches we can take for custom classes.
Programming Task | Python JSON Library Function or Class. Names assume: import json | Advantages | Disadvantages |
Convert a Python dictionary to a JSON string | json.dumps | Extremely flexible and easy to use. Very little code. | Dictionaries as an internal data format are convenient but can be harder to maintain. Class members provide better documentation than dictionary keys of what an object should contain. |
Convert a JSON String to a Python dictionary | json.loads | As above | As above |
Write a Python dictionary object to a JSON file | json.dump | As above | As above |
Read a JSON file to a Python Dictionary object | json.load | As above | as above |
Reading and Writing a Custom Python Object to JSON | Approach 1: Add methods to the class itself. The JSON library may not be needed. | Convenient and obvious to readers of the class code. Methods is more likely to get maintained when the class changes. | Might lead to inconsistencies if it doesn't need to be done for all classes. Does not integrate with JSON package. May lead to invalid JSON. |
Reading and Writing a Custom Python Object to JSON | Approach 2: Write a custom json JSONDecoder and JSONEncoder. | Allows JSON functionality to follow "single responsibility" principle. Doesn't add functionality to class that it doesn't need natively. | May be unclear that it needs to be maintained when class changes. Increases code complexity. |