Python program to convert a dictionary to JSON

How to convert a dictionary to JSON in python:

In this post, we will learn how to convert a dictionary to JSON in python. JSON or JavaScript Object Notation is a popular format that is used widely for interchange and store data.

It has many advantages like it is lightweight, it is easy for human and programming languages to read etc.

A JSON object can have key-value pairs and an array of values.

For example, the below is a JSON object:

{"name" : "Alex", "age" : 10}

For this object, two keys are there name and age and values for name is Alex and for age is 10.

What is dictionary in Python:

Dictionaries are use to store key-value pairs in Python. We can create a dictionary by putting all key-value pairs within a curly braces. For example:

givenDict = {"name": "Alex", "age": 19}

givenDict is a dictionary.

We can’t have any duplicate keys in python.

Converting dictionary to JSON in python:

We can convert a dictionary to a JSON object easily in python. Python provides a module called json that provides different methods to work with JSON values.

It provides a method called dumps, that can be used to convert a dictionary to JSON. This method returns the converted JSON value.

Python example program to convert dictionary to JSON:

Let’s take a look at the below program:

import json

givenDict = {"name": "Alex", "age": 19}

jsonDict = json.dumps(givenDict)

print(jsonDict)

For this example,

We are using import json to import the json module. dumps method is defined in this module.
givenDict is the given dictionary.
We are using json.dumps to convert the dictionary to a JSON and that value is stored in jsonDict.
The last line is printing the JSON data.

If you run this, it will print the below output:

{"name": "Alex", "age": 19}

Pretty print a JSON:

We can pass one more parameter index to json.dumps with a non-negative value. This is an integer value and it defines the indent level to use for pretty-print the JSON.

For example,

import json

givenDict = {"name": "Alex", "age": 19, "grade": "A"}

jsonDict = json.dumps(givenDict, indent=4)

print(jsonDict)

It will print:

{
    "name": "Alex",
    "age": 19,
    "grade": "A"
}

indent with None will make the most compact JSON.

And, if you pass 0, it will only insert newlines as like below:

{
"name": "Alex",
"age": 19,
"grade": "A"
}

Sorting the keys of a JSON:

We can also sort the keys of a JSON by using dumps. For that, we have to pass another parameter called sort_keys. This is False by default. If we pass True, it will sort the keys of the JSON.

For example,

import json

givenDict = {"name": "Alex", "age": 19, "grade": "A"}

jsonDict = json.dumps(givenDict, indent=4, sort_keys=True)

print(jsonDict)

It will sort the keys of the final JSON and print the data as like below:

{
    "age": 19,
    "grade": "A",
    "name": "Alex"
}

Writing Dictionary to a JSON file:

There is another method called dump defined in the json module. This method can be used to write the content of a dictionary to a file. It can be a JSON file or any other file.

This method takes two parameters: the first one is the dictionary that we need to convert and write and the second one is the pointer to the file.

For example:

import json

givenDict = {"name": "Alex", "age": 19, "grade": "A"}

with open("data.json", "w") as f:
    json.dump(givenDict, f)

It will print the content of givenDict to a file data.json.

You can also change the indent and sort the keys similar to dumps.

import json

givenDict = {"name": "Alex", "age": 19, "grade": "A"}

with open("data.json", "w") as f:
    json.dump(givenDict, f, indent=4, sort_keys=True)

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