To convert a dictionary to a JSON string in Python, use the built-in json.dumps() method. If you want to write a json file, use the json.dump() method.

As you can see from the above picture, the json.dumps() method accepts a dictionary as input and converts it into a JSON-formatted string.

import json

app_dict = {
    'name': 'messenger',
    'playstore': True,
    'company': 'Meta',
    'price': 100
}

print(app_dict)
# Output: {'name': 'messenger', 'playstore': True, 'company': 'Meta', 'price': 100}

print(type(app_dict))
# Output: <class 'dict'>

app_json = json.dumps(app_dict)


print(app_json)
# Output: {"name": "messenger", "playstore": true, "company": "Meta", "price": 100}

print(type(app_json))
# Output: <class 'str'>

If you analyze the output carefully, you can see that the Keys and string values are quoted; numbers and booleans are not.

Using a Nested Dictionary

If the input is a nested dictionary, it will create a json string with the same level of nesting.

import json

nested_app_dict = {
    'app_info': {
        'name': 'messenger',
        'playstore': True
    },
    'company_info': {
        'company_name': 'Meta',
        'price': 100
    }
}

print(nested_app_dict)
# Output:
# {'app_info': {'name': 'messenger', 'playstore': True},
#  'company_info': {'company_name': 'Meta', 'price': 100}}

print(type(nested_app_dict))
# Output: <class 'dict'>

app_json = json.dumps(nested_app_dict, indent=3)

print(app_json)
# Output:
# {
#    "app_info": {
#       "name": "messenger",
#       "playstore": true
#    },
#    "company_info": {
#       "company_name": "Meta",
#       "price": 100
#    }
# }

print(type(app_json))
# Output: <class 'str'>

While using json.dumps(), we passed indent = 3 argument for pretty-print json, which improves the readability of the JSON output, especially for nested structures.

Sorting Keys

import json

app_dict = {
    'name': 'messenger',
    'playstore': True,
    'company': 'Meta',
    'price': 100
}

print(app_dict)
# Output: {'name': 'messenger', 'playstore': True, 'company': 'Meta', 'price': 100}

print(type(app_dict))
# Output: <class 'dict'>

app_json = json.dumps(app_dict, sort_keys=True)

print(app_json)
# Output: {"company": "Meta", "name": "messenger", "playstore": true, "price": 100}

print(type(app_json))
# Output: <class 'str'>

import json

app_dict = {
    'name': 'messenger',
    'playstore': True,
    'company': 'Meta',
    'price': 100
}

print(app_dict)
# Output: {'name': 'messenger', 'playstore': True, 'company': 'Meta', 'price': 100}

print(type(app_dict))
# Output: <class 'dict'>

arr = [{x: app_dict[x]} for x in app_dict]

app_json_arr = json.dumps(arr, indent=3)

print(app_json_arr)
# Output:
# [
#    {
#       "name": "messenger"
#    },
#    {
#       "playstore": true
#    },
#    {
#       "company": "Meta"
#    },
#    {
#       "price": 100
#    }
# ]

print(type(app_json_arr))
# Output: <class 'str'>

You use the json.dump() method to write the dictionary to the file in JSON format.

The “with statement” context manager ensures the file is properly handled and closed after writing.

import json

app_dict = {
    'name': 'messenger',
    'playstore': True,
    'company': 'Meta',
    'price': 100
}

print(app_dict)
# Output: {'name': 'messenger', 'playstore': True, 'company': 'Meta', 'price': 100}

print(type(app_dict))
# Output: <class 'dict'>

with open('app.json', 'w') as json_file:
    json.dump(app_dict, json_file)

print("Dictionary has been successfully written to JSON File")

# Output: Dictionary has been successfully written to JSON File

Here is the written app.json file:

That’s all!

Krunal Lathiya

With a career spanning over eight years in the field of Computer Science, Krunal’s expertise is rooted in a solid foundation of hands-on experience, complemented by a continuous pursuit of knowledge.