JSON Dumps() in Python

Parameters of json.dump() in Python

The json.dump() function in Python is used to write JSON data to a file-like object. Here are the commonly used parameters:

• obj: This is the Python object to be serialized to JSON format.
• fp: This is the file-like object where the JSON data will be written.
• skipkeys: A boolean value (default is False). If set to True, it skips keys in the obj that are not serializable.
• ensure_ascii: A boolean value (default is True). If set to True, it escapes non-ASCII characters as Unicode escape sequences. Setting it to False allows non-ASCII characters to be written as is.
• check_circular: A boolean value (default is True). Setting to False turns off checking for circular references within the data structure.

Return Values of json.dump() in Python

The json.dump() function in Python does not return a value. It writes the serialized JSON to the file-like object specified by the fp parameter. If you want to get the serialized JSON as a string, you can use the json.dumps() function instead.
The json.dumps() function takes the same parameters as the json.dump() function returns the serialized JSON as a string instead of writing it to a file.

Usage of JSON Dumps Function

Here are some of the uses of the JSON dumps function.

1. Converting a Dictionary to a JSON String

Json Dumps can be used to convert a dictionary into a JSON String.

• Python

Python

import json

data = {'name': 'John', 'age': 30, 'city': 'New York'}
json_string = json.dumps(data)
print(json_string)

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Output:

Explanation

Here, the data dictionary is passed as an argument to json.dumps(), which returns a JSON formatted string representing the dictionary.

2. Converting a List to a JSON String

Json Dumps is also used to convert a list into a JSON String.

• Python

Python

import json

data = ['apple', 'banana', 'cherry']
json_string = json.dumps(data)
print(json_string)

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Output:

Explanation

Here, the list is passed as an argument to json.dumps(), which returns a JSON formatted string representing the data list.

3. Format the JSON String with Indentation

Now we will discuss an example using the indent parameter to format the JSON string with indentation.

• Python

Python

import json

data = {'name': 'John', 'age': 30, 'city': 'New York'}
json_string = json.dumps(data, indent=4)
print(json_string)

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Output:

Explanation

In this code, Dictionary is passed as the first argument, and indent=4 is also given for the specific indentation and json.dumps() makes the indentation with four spaces.

4. Serialising a Python Object to a JSON String

Let us take an example of using a custom encoder to serialise a Python object to a JSON string.

• Python

Python

import json

class Person:
    def __init__(self, name, age):
        self.name = name
        self.age = age
    
def person_encoder(obj):
    if isinstance(obj, Person):
        return {'name': obj.name, 'age': obj.age}
    else:
        raise TypeError('Object of type Person is not JSON serializable')
        
person = Person('John', 30)
json_string = json.dumps(person, default=person_encoder)
print(json_string)

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Output:

Explanation

In this code, a Person class is defined with two arguments, name and age. json.dumps() method is called with the person as the first argument and the person_encoder() function as the default argument. This tells the json module to use the person_encoder() function to encode any Person objects it encounters during serialization.

Difference between JSON dump () and JSON dumps ()

Frequently Asked Questions

How to parse JSON dumps?

You can parse JSON dumps using json.loads() in Python, which converts a JSON string into a Python dictionary or list.

What does dump() do?

json.dump() serializes Python objects into JSON format and writes it to a file. It is used for saving data in JSON format.

Is JSON easy to parse?

Yes, JSON is easy to parse because it’s a lightweight, text-based format that’s straightforward to convert into native data structures using built-in functions like JSON.parse() in JavaScript or json.loads() in Python.

Conclusion

This article discusses the topic of JSON Dumps. We hope this blog has helped you enhance your knowledge of JSON Dumps. 

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