Python JSON Serialize Set
You are here because when you try to dump or encode Python set into JSON, you received an error, TypeError: Object of type set is not JSON serializable .
The built-in json module of Python can only handle Python primitives types that have a direct JSON equivalent. i.e., The fundamental problem is that the JSON encoder json.dump() and json.dumps() only knows how to serialize the basic types by default (e.g., dictionary, lists, strings, numbers, None, etc.). To solve this, we need to build a custom encoder to make set JSON serializable.
Further Reading:
In this article, we will see how to JSON Serialize Set. There are multiple ways to accomplish this.
Use the jsonpickle module to make Python set JSON serializable
jsonpickle is a Python library designed to work with complex Python Objects. You can use jsonpickle for serialization complex Python objects into JSON. Also, and deserialization from JSON to complex Python objects. jsonpickle allows more complex data structures to be serialized to JSON. jsonpickle is highly configurable and extendable.
- Install jsonpickle using pip. pip install jsonpickle
- Execute jsonpickle.encode(object) to serialize custom Python Object.
You can refer to Jsonpickle Documentation for more detail. Let’s see the jsonpickle example to make a set JSON serializable.
import json import jsonpickle from json import JSONEncoder sampleSet = print("Encode set into JSON using jsonpickle") sampleJson = jsonpickle.encode(sampleSet) print(sampleJson) # Pass sampleJson to json.dump() if you want to write it in file print("Decode JSON into set using jsonpickle") decodedSet = jsonpickle.decode(sampleJson) print(decodedSet) # to check if we got set after decoding decodedSet.add(95) print(decodedSet)Encode set into JSON using jsonpickle Decode JSON into set using jsonpickle
Use custom JSON Encoder to make Python set JSON serializable
Let’ see how to write custom encoder to JSON serializable Python set. Python json module provides a JSONEncoder to encode python types into JSON. We can extend by implementing its default() method that can JSON serializable set.
In default() method we will convert set into list using list(setObj)
The json.dump() and json.dumps() methods of the json module has a cls kwarg . Using this argument, you can pass a custom JSON Encoder, which tells dump or dumps method how to encode set into JSON formatted data.
JSONEncoder class has a default() method which will be used when we execute JSONEncoder.encode(object) . This method converts only basic types into JSON.
Your custom JSONEncoder subclass will override the default() method to serialize additional types. Specify it with the cls kwarg in json.dumps() method; otherwise, default JSONEncoder is used. Example: json.dumps(cls=CustomEncoder) .
import json from json import JSONEncoder # subclass JSONEncoder class setEncoder(JSONEncoder): def default(self, obj): return list(obj) sampleSet = print("Encode Set and Printing to check how it will look like") print(setEncoder().encode(sampleSet)) print("Encode Set nto JSON formatted Data using custom JSONEncoder") jsonData = json.dumps(sampleSet, indent=4, cls=setEncoder) print(jsonData) # Let's load it using the load method to check if we can decode it or not. setObj = json.loads(jsonData, object_hook=customSetDecoder) print("Decode JSON formatted Data") print(setObj) Encode Set and Printing to check how it will look like [65, 25, 85, 45] Encode Set nto JSON formatted Data using custom JSONEncoder [ 65, 25, 85, 45 ] Decode JSON formatted Data [65, 25, 85, 45]
So What Do You Think?
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Also, try to solve the Python JSON Exercise to have a better understanding of Working with JSON Data in Python.
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About Vishal
I’m Vishal Hule, Founder of PYnative.com. I am a Python developer, and I love to write articles to help students, developers, and learners. Follow me on Twitter
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