Python JSON

Python JSON (JavaScript Object Notation)¶

Introduction to JSON in Python¶

• JSON (JavaScript Object Notation) is a lightweight format for storing and exchanging data.
• Python provides a built-in json module for working with JSON.
• JSON is widely used in web applications, APIs, and data exchange.

Parsing JSON: Convert JSON to Python¶

• The json.loads() method converts a JSON-formatted string into a Python dictionary.

In [1]:

import json

# JSON data as a string
json_data = '{ "name": "Alice", "age": 25, "city": "London"}'

# Convert JSON string to Python dictionary
python_dict = json.loads(json_data)

# Access values from the dictionary
print(python_dict["name"])  # Output: Alice
print(python_dict["age"])   # Output: 25

Alice
25

Converting Python Objects to JSON¶

• The json.dumps() method converts Python objects into a JSON string.
• Supported Python data types for conversion:
  • dict, list, tuple, str, int, float, bool, None

In [2]:

import json

# Python dictionary
data = {
    "name": "Alice",
    "age": 25,
    "city": "London"
}

# Convert to JSON string
json_string = json.dumps(data)

print(json_string)  # Output: {"name": "Alice", "age": 25, "city": "London"}

{"name": "Alice", "age": 25, "city": "London"}

Example Conversions¶

In [3]:

print(json.dumps({"language": "Python", "version": 3.10}))  # Dictionary to JSON
print(json.dumps(["ML", "AI", "Deep Learning"]))            # List to JSON
print(json.dumps(("NLP", "Computer Vision")))               # Tuple to JSON
print(json.dumps(42))                                       # Integer to JSON
print(json.dumps(19.99))                                    # Float to JSON
print(json.dumps(True))                                     # Boolean to JSON
print(json.dumps(None))                                     # None to JSON

{"language": "Python", "version": 3.1}
["ML", "AI", "Deep Learning"]
["NLP", "Computer Vision"]
42
19.99
true
null

Python to JSON Mapping¶

Python Data Type	JSON Equivalent
dict	Object
list	Array
tuple	Array
str	String
int	Number
float	Number
True	true
False	false
None	null

Working with Complex JSON Data¶

• JSON can store nested data structures like lists and dictionaries.

In [4]:

import json

# Complex Python data structure
user_profile = {
    "name": "Alice",
    "age": 25,
    "skills": ["Python", "Machine Learning"],
    "education": {
        "degree": "MSc",
        "field": "Computer Science"
    },
    "certified": True
}

# Convert Python dictionary to JSON
json_data = json.dumps(user_profile)

print(json_data)

{"name": "Alice", "age": 25, "skills": ["Python", "Machine Learning"], "education": {"degree": "MSc", "field": "Computer Science"}, "certified": true}

Formatting JSON Output¶

• JSON output can be formatted for readability using indent.

In [5]:

import json

# Nested dictionary
data = {
    "name": "Alice",
    "age": 25,
    "skills": ["Python", "Data Science"],
    "projects": [
        {"title": "NLP Model", "status": "Completed"},
        {"title": "Computer Vision", "status": "In Progress"}
    ]
}

# Convert to JSON with indentation
formatted_json = json.dumps(data, indent=4)

print(formatted_json)

### **Output:**
# {
#     "name": "Alice",
#     "age": 25,
#     "skills": [
#         "Python",
#         "Data Science"
#     ],
#     "projects": [
#         {
#             "title": "NLP Model",
#             "status": "Completed"
#         },
#         {
#             "title": "Computer Vision",
#             "status": "In Progress"
#         }
#     ]
# }

{
    "name": "Alice",
    "age": 25,
    "skills": [
        "Python",
        "Data Science"
    ],
    "projects": [
        {
            "title": "NLP Model",
            "status": "Completed"
        },
        {
            "title": "Computer Vision",
            "status": "In Progress"
        }
    ]
}

Customizing JSON Separators¶

• The default separator in JSON output is ", " for items and ": " for key-value pairs.
• We can change the separators for a more compact output.

In [7]:

import json

data = {
    "name": "Alice",
    "age": 25,
    "skills": ["Python", "Data Science"]
}

# Custom separator
compact_json = json.dumps(data, indent=4, separators=(". ", " = "))

print(compact_json)
### **Output:**
# {
#     "name" = "Alice".
#     "age" = 25.
#     "skills" = [
#         "Python".
#         "Data Science"
#     ]
# }

{
    "name" = "Alice". 
    "age" = 25. 
    "skills" = [
        "Python". 
        "Data Science"
    ]
}

Sorting Keys in JSON Output¶

• The sort_keys=True parameter sorts the dictionary keys alphabetically.

In [8]:

import json

data = {
    "age": 25,
    "name": "Alice",
    "city": "London"
}

# Convert to JSON with sorted keys
sorted_json = json.dumps(data, indent=4, sort_keys=True)

print(sorted_json)
### **Output:**
# {
#     "age": 25,
#     "city": "London",
#     "name": "Alice"
# }

{
    "age": 25,
    "city": "London",
    "name": "Alice"
}