JSON pickling

json.dumps() and json.dump()

• They’re both for serializing Python objects into JSON format, but they differ in their output destination
• 📌indent
  • Use this to indicate each level of indentation in the JSON output (number of spaces)

json.dumps()

• Converts a Python object (like a dictionary or list) into a JSON-formatted string.
  • Returns a string containing the JSON representation of the Python object. 
  • The “s” in dumps stands for “dump string.”

import json
a = ['foo', {'bar': ('baz', None, 1.0, 2)}]
test = json.dumps(a)
print(test)
#["foo", {"bar": ["baz", null, 1.0, 2]}]

• `dumps
  • Converts Python data into json
  • ```None“ → null
  • '' → ""
  • tuples → list

If we have a custom class:

import json
 
class Cat:
	def __init__(self, name, breed):
		self.name = name
		self.breed = breed
c = Cat("Cheese", "Tabby")
 
j = json.dumps(c.__dict__)
print(j) # {"name": "Cheese", "breed": "Tabby"}

json.dump()

• Serializes a Python object into a JSON-formatted string and writes it directly to a file-like object (e.g., a file opened in write mode).
  • Writes the JSON data directly to the specified file, rather than returning a string.
  • Ideal when you want to save Python data structures directly into a JSON file.

import json
 
data = {
    "name": "Bob",
    "age": 25,
    "city": "London"
}
 
with open("output.json", "w") as f:
    json.dump(data, f, indent=4)

jsonpickle

python3 -m pip install jsonpickle

import jsonpickle
 
class Cat:
	def __init__(self, name, breed):
		self.name = name
		self.breed = breed
c = Cat("Cheese", "Tabby")
 
frozen = jsonpickle.encode(c)
print(frozen)
# {"py/object": "__main__.Cat", "name": "Cheese", "breed": "Tabby"}
 
unfrozen = jsonpickle.decode(frozen)
print(unfrozen)
# <__main__.Cat object at 0x7fc1d310b2c0>