json Dump Python With Example

Here, you’ll learn how to use the Python json module to save Python serialized objects as JSON formatted data to a file or a string using the Python JSON module. We’ll discuss python dump method here.

The JSON module has two methods for converting Python objects to JSON format:

• The json.dump() used to write Python serialized object as JSON formatted data into a file.
• The json.dumps() method is used to encodes any Python object into JSON formatted String.

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The above methods will help to do following operations:

• Python serialised objects are encoded as JSON structured data.
• Write Python objects to a JSON file by encoding and decoding them.
• PrettyPrinted JSON data
• Skip nonbasic types while JSON encoding
• Perform compact encoding to save file space
• Handle non-ASCII data while encoding JSON

json.dump() method

The json.dump() method is used to write a Python object into a file as JSON formatted data.

Syntax of json.dump():

json.dump(obj, fp, *, skipkeys=False, ensure_ascii=True, check_circular=True, allow_nan=True, cls=None, indent=None, separators=None, default=None, sort_keys=False, **kw)

json.dumps() method

The json.dumps() method is used to write a Python object into a JSON String..

Syntax of json.dumps():

json.dumps(obj, *, skipkeys=False, ensure_ascii=True, check_circular=True, allow_nan=True, cls=None, indent=None, separators=None, default=None, sort_keys=False, **kw)

Parameters:

• obj : This is a Python serializable object which you want to convert into a JSON format.
• fp: Thiis is a file pointer used to write JSON formatted data into file.
• skipkeys (default: False): when it true then dict keys that are not of a basic type, (str, int, float, bool, None) will be skipped instead of raising a TypeError.
• ensure_ascii (default: True): The result will have all incoming non-ASCII characters escaped. If false, these characters will be output as-is.
• allow_nan (default: True): JavaScript equivalents (NaN, Infinity, -Infinity) will be used. If False it will be a ValueError to serialize out of range float values (nan, inf, -inf).
• indent : It’s used to pretty-print JSON to make it more readable.
• sort_keys (default: False) : The output of dictionaries will be sorted by key if its set to True

How To Use json.dump() method

Let’s convert Python dictionary into a JSON formatted String using json.dumps() method.

import json

# sample dict
test_Dict = {
    "name": "Adam",
    "age": 40,
    "salary": 5400
}
js_str = json.dumps(test_Dict)
print(js_str)

Output:

{"name": "Adam", "age": 40, "salary": 5400}

json dump To file Using json.dump() method

In this example, we are going to convert the Python dictionary into a JSON format and write it into a file.

import json

sampleDict = {
    "name": "Adam",
    "age": 40,
    "salary": 5400
}

with open("employee.json", "w") as write_file:
    json.dump(sampleDict, write_file) # encode dict into JSON
print("Done writing JSON data into .json file")

Output:

Done writing JSON data into .json file