Sometimes, we want to JSON serialize sets with Python.

In this article, we’ll look at how to JSON serialize sets with Python.

How to JSON serialize sets with Python?

To JSON serialize sets with Python, we can use the json.dumps method with a custom json.JSONEncoder subclass.

For instance, we write

import json

class SetEncoder(json.JSONEncoder):
   def default(self, obj):
      if isinstance(obj, set):
         return list(obj)
      return json.JSONEncoder.default(self, obj)

s = json.dumps(set([1,2,3,4,5]), cls=SetEncoder)

to create the SetEncoder class which is subclass of the json.JSONEncoder class.

In it, we add the default method.

And in the default method, we return the set converted to a list if the obj object is a set.

And then we call json.JSONEncoder.default(self, obj) to serialize the obj object.

Next, we call json.dumps with a set and the cls argument set to SetEncoder to use SetEncoder to serialize the set into a JSON string.

Conclusion

To JSON serialize sets with Python, we can use the json.dumps method with a custom json.JSONEncoder subclass.