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Bite-sized Python tips to write cleaner, smarter, and faster code. Learn best practices, refactoring techniques, and optimization strategies to improve your Python skills and code quality.
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💡 In Python 3.14, uuid6, uuid7, and uuid8 were added:
UUID v6 → monotonic, time-ordered replacement for v1 (better sorting, no MAC leaks).
UUID v7 → combines timestamp ordering with randomness → great for DB primary keys.
UUID v8 → custom format playground for app-specific needs.
📌 #python_3_14 #uuid #databases #performance #customization
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Py Snack 🍿
Mar 29, 2026, 08:17 AM
🚫 Before:
data = b"abcdef" * 10**6
chunk = data[2:5] # makes a copy
✅ After:
# settings.py
data = b"abcdef" * 10**6
view = memoryview(data)[2:5] # zero-copy slice
🧠 ➤ memoryview avoids copying — slicing large bytes / bytearray objects creates views instead of duplicating data.
Perfect for parsing network packets, binary protocols, or huge files without ballooning memory usage.
📌 #memory #performance #python_internals #best_practices
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Py Snack 🍿
Mar 29, 2026, 08:17 AM
🚫 Before:
from contextvars import ContextVar
A = ContextVar("A")
token = A.set("val")
try:
...
finally:
A.reset(token)
✅ After (3.14+):
from contextvars import ContextVar
A = ContextVar("A")
with A.set("val"):
...
🧠 ➤ Token is now a context manager.
📌 #python_3_14 #contextvars #clean_code #syntax_sugar
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Py Snack 🍿
Mar 29, 2026, 08:17 AM
🚫 Before:
from uuid import uuid4
key = uuid4() # unique, but unordered
✅ After (3.14+):
from uuid import uuid7
key = uuid7() # unique + chronologically sortable
🧠 ➤ UUID v7 combines randomness with time ordering — perfect for DB keys (uniqueness + natural sort).
📌 #python_3_14 #uuid #databases #performance
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Py Snack 🍿
Mar 29, 2026, 08:17 AM
🚫 Before:
if user.is_admin:
delete_all_data()
else:
raise PermissionError("Not allowed!")
✅ After (Python 3.11+):
user.is_admin or raise PermissionError("Not allowed!")
delete_all_data()
🧠 ➤ raise as an expression makes the code shorter and cleaner.
📌 #basics #clean_code #syntax_sugar #python_3_11 #exceptions #tips #best_practices #control_flow
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Py Snack 🍿
Mar 29, 2026, 08:17 AM
🚫 Before:
def get_config_value(key: str) -> str:
with open("config.json") as f:
config = json.load(f)
return config[key]
✅ After:
from functools import cache
@cache
def get_config_value(key: str) -> str:
with open("config.json") as f:
config = json.load(f)
return config[key]
🧠 ➤ https://t.me/cache prevents repeated file reads (static configs only - use https://t.me/lru_cache(1) + os.path.getmtime() for dynamic)
📌 #basics #functions #performance #cache #functools #pythonic #clean_code #tips #optimization
92
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Py Snack 🍿
Mar 29, 2026, 08:17 AM
🚫 Before:
class Singleton:
_instance: "Singleton" | None = None
def __new__(cls, *args, **kwargs):
if cls._instance is None:
cls._instance = super().__new__(cls)
return cls._instance
✅ After:
# settings.py
class Settings:
...
settings = Settings()
🧠 ➤ Python modules are already singletons by nature — no need for custom Singleton classes that introduce hidden state, inheritance issues, and confusing behavior.
📌 #basics #pitfalls #singleton #clean_code #pythonic
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Py Snack 🍿
Mar 29, 2026, 08:17 AM
🚫 Before:
for item in data:
try:
self.assertEqual(process(item), expected(item))
except AssertionError as e:
print(f"Failed for {item}: {e}")
✅ After (Python 3.13+):
from test.support import subTests
with subTests(self):
for item in data:
with self.subTest(item=item):
self.assertEqual(process(item), expected(item))
🧠 ➤ subTests from http://test.support/ simplifies running multiple assertions inside one test.
➤ Failures in one subtest don’t stop others — better granularity and clearer reports.
➤ Perfect for parameterized or bulk input testing.
📌 #basics #testing #unittest #pythonic #3_13_update #subTests #clean_code #tips #test_automation
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Py Snack 🍿
Mar 29, 2026, 08:17 AM
🚫 Before:
def calculate_discount(price: float, discount: float) -> float:
"""Calculate final price after discount."""
if price < 0:
raise ValueError("Price cannot be negative")
if not 0 <= discount <= 100:
raise ValueError("Discount must be between 0 and 100")
return price * (1 - discount / 100)
✅ After:
from pydantic import validate_call
from typing import Annotated
from pydantic.types import Gt, Ge, Le
@validate_call
def calculate_discount(
price: Annotated[float, Gt(0)],
discount: Annotated[float, Ge(0), Le(100)]
) -> float:
return price * (1 - discount / 100)
🧠 ➤ typing. Annotated with predicates like Gt/Le (from pydantic or typing_extensions) embeds constraints directly in type hints, keeping signatures self-documenting while staying type-checker friendly.
📌 #basics #pydantic #typing #annotations #validation #pythonic #clean_code #tips #type_safety #best_practices
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Py Snack 🍿
Mar 29, 2026, 08:17 AM
🚫 Before:
def clean(data: list[int]) -> list[int]:
for x in data:
if x < 0:
data.remove(x)
return data
print(clean([1, -2, -3, 4])) # [1, -3, 4]
✅ After:
def clean(data: list[int]) -> list[int]:
return [x for x in data if x >= 0]
print(clean([1, -2, -3, 4])) # [1, 4]
🧠 ➤ Removing while iterating shifts indexes and skips items.
📌 #basics #lists #pythonic #clean_code #pitfalls #tips #list_comprehension #best_practices #performance
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Py Snack 🍿
Mar 17, 2026, 11:57 PM
🚫 Before:
if user.is_authenticated:
send_welcome_email(user)
✅ After
user.is_authenticated and send_welcome_email(user)
🧠 ➤ In Python, and evaluates the second expression only if the first is true, enabling concise conditional calls without else.
📌 #basics #clean_code #short_circuit #tips #syntax_sugar #best_practices
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Py Snack 🍿
Dec 6, 2025, 02:42 AM
🚫 Before:
def move_file(src, dst, overwrite=False): ...move_file("a.txt", "b.txt", True)
✅ After
def move_file(src, dst, /, *, overwrite=False): ...move_file("a.txt", "b.txt", overwrite=True)
🧠 ➤ / makes src and dst positional-only — prevents accidental argument mix-ups.
➤ * makes overwrite keyword-only — avoids confusing third positional arg.
📌 ?q=%23basics ?q=%23functions ?q=%23clean_code
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Py Snack 🍿
Dec 6, 2025, 02:42 AM
🚫 Before:
if type(obj) == list: handle_list(obj)
✅ After
if isinstance(obj, list): handle_list(obj)
🧠 ➤ type(obj) == list checks for exact type only — won’t catch subclasses!
➤ isinstance considers inheritance — more correct and flexible.
➤ Use isinstance for type checks by default.
📌 ?q=%23basics ?q=%23pitfalls ?q=%23type_checking ?q=%23isinstance ?q=%23clean_code ?q=%23oop ?q=%23tips
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Py Snack 🍿
Dec 3, 2025, 07:34 AM
🚫 Before:
import asyncio, aiohttpTOTAL_REQUESTS = 1_000_000async def fetch(session, url): async with session.get(url) as resp: return await resp.text()async def main(): urls = [f"https://api.site/{i}" for i in range(TOTAL_REQUESTS)] async with aiohttp. ClientSession() as session: tasks = [fetch(session, url) for url in urls] await asyncio.gather(*tasks) # 💥 OOM / rate-limitasyncio.run(main())
✅ After
import asyncio, aiohttpTOTAL_REQUESTS = 1_000_000sem = asyncio. Semaphore(1000)async def fetch(session, url): async with sem: try: async with session.get(url) as resp: return await resp.text() except aiohttp. ClientError: return Noneasync def main(): urls = [f"https://api.site/{i}" for i in range(TOTAL_REQUESTS)] async with aiohttp. ClientSession() as session: for i in range(0, len(urls), 10_000): chunk = urls[i:i+10_000] tasks = [fetch(session, url) for url in chunk] await asyncio.gather(*tasks)asyncio.run(main())
🧠 ➤ Avoid memory blowups & rate-limit bans. Use semaphores + chunking like a pro.
📌 ?q=%23asyncio ?q=%23aiohttp ?q=%23performance
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