How to Read a JSON Configuration File in Python

In many software projects, there is a need to utilize some form of configuration that can be easily managed and accessed. A popular choice for such a configuration file format is JSON (JavaScript Object Notation). In this tutorial, we’ll be discussing how to read a JSON configuration file in Python.

What is a JSON file?

A part of popular data exchange formats on the web, JSON is a text format that is completely language-independent but uses conventions that are familiar to programmers of the C-family of languages, including C, C++, C#, Java, JavaScript, Perl, Python, and many others. JSON structures can easily be read and written in Python with a basic understanding of lists and dictionaries, which makes it easy to work with.

Step 1: Importing necessary Python libraries

In Python, we have the built-in json module that allows us to read and write data in JSON format.

1
import json

Step 2: Open and load the JSON file

We can read the JSON file using the open() function and use the json.load() function to parse the JSON data.

1
2
with open('config.json') as file:
    data = json.load(file)
 
{
  "name": "John",
  "age": 30,
  "city": "New York"
}

Step 3: Access the JSON data

The JSON data is now stored into a Python object called ‘data’. We can easily access the values by treating it like a dictionary.

1
2
3
print(data['name'])
print(data['age'])
print(data['city'])

Full code

1
2
3
4
5
6
7
8
import json
 
with open('config.json') as file:
    data = json.load(file)
 
print(data['name'])
print(data['age'])
print(data['city'])

Output

"John"
"30"
"New York"

Conclusion

In this tutorial, we have covered how to read a JSON configuration file in Python. JSON is a widely used data format, and Python’s built-in json module makes it very easy to read such files and access the data within them.

Remember that the JSON file’s data is converted into a Python dictionary that you can access and manipulate like any other dictionary.