Python 3.12: New Features You Should Know

Python 3.12 brings several exciting new features and optimizations. Let’s dive into the most significant changes.

1. Pattern Matching Enhancements

Pattern matching (introduced in Python 3.10) gets even better:

# More powerful pattern matching
match point:
    case (x, y) if x == y:
        print(f"Y = X at {x}")
    case (0, y):
        print(f"X=0 and Y={y}")
    case (x, 0):
        print(f"Y=0 and X={x}")
    case _:
        print("Some other point")

2. Performance Improvements

Python 3.12 includes several performance optimizations:

• Faster method calls: Up to 20% faster
• Reduced memory usage: More efficient object handling
• Improved startup time: Faster interpreter initialization

3. New Type System Features

Type Parameter Syntax

def find_first[T](items: list[T], target: T) -> int | None:
    for i, item in enumerate(items):
        if item == target:
            return i
    return None

TypedDict Improvements

from typing import TypedDict, Required, NotRequired

class Movie(TypedDict):
    title: str
    year: NotRequired[int]
    rating: Required[float]

# This is valid
movie: Movie = {"title": "The Matrix", "rating": 8.7}

4. New Standard Library Modules

tomllib for TOML Parsing

import tomllib

with open("config.toml", "rb") as f:
    config = tomllib.load(f)

5. Error Messages

More helpful error messages make debugging easier:

# Old error:
# TypeError: unsupported operand type(s) for +: 'int' and 'str'

# New error:
# TypeError: can only concatenate str (not "int") to str

6. New String Methods

# Remove prefix/suffix (now even more efficient)
url = "https://example.com"
clean_url = url.removeprefix("https://")  # "example.com"

# Case-insensitive string comparison
"Python".casefold() == "python"  # True

7. Asyncio Improvements

import asyncio

async def main():
    # New timeout context manager
    try:
        async with asyncio.timeout(10):  # 10 second timeout
            await long_running_task()
    except TimeoutError:
        print("The task took too long!")

Conclusion

Python 3.12 continues to improve the language with better performance, enhanced type hints, and more developer-friendly features. Whether you’re working on web development, data science, or automation, these new features will make your Python code more efficient and maintainable.