Python Dictionaries Guide

Python Dictionaries: A Complete Guide for Beginners

Python dictionaries allow developers to store and manage data in a key-value pair format, making them essential for efficient data manipulation.

What is a Python Dictionary?

A Python dictionary is an unordered, mutable, and indexed collection of key-value pairs.

As of Python version 3.7, dictionaries are ordered. In Python 3.6 and earlier, dictionaries are unordered.

Creating a Dictionary

student = {
    "name": "John Doe",
    "age": 20,
    "course": "Computer Science"
}

device = dict(brand="Apple", model="iPhone 13", price=999)

Accessing Dictionary Elements

print(student["name"])  # Output: John Doe
print(device.get("brand"))  # Output: Apple

Modifying a Dictionary

student["age"] = 21
student["grade"] = "A"
device.pop("price")

Dictionary Methods

• keys() – Returns a list of keys.
• values() – Returns a list of values.
• items() – Returns a list of key-value pairs.
• update() – Merges another dictionary into the existing one.
• pop() – Removes an item based on the key.

print(student.keys())
print(student.values())

Dictionary Comprehension

squares = {x: x*x for x in range(1, 6)}
print(squares)

Use Cases of Dictionaries

• Storing configurations in applications.
• Caching and memoization for performance optimization.
• Representing JSON data in APIs.
• Grouping and counting occurrences in datasets.

Conclusion

Python dictionaries are an indispensable tool for developers, offering efficiency, flexibility, and ease of use.

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