DEV Community

Anna lilith
Anna lilith

Posted on

10 Python One-Liners Every Developer Should Know

#python #beginners #tips #programming

Python one-liners that save time and look impressive.

1. Flatten a List 

flat = [item for sublist in nested for item in sublist]
Enter fullscreen mode Exit fullscreen mode

2. Count Occurrences 

from collections import Counter
counts = Counter(my_list)
Enter fullscreen mode Exit fullscreen mode

3. Dictionary Comprehension 

squared = {x: x**2 for x in range(10)}
Enter fullscreen mode Exit fullscreen mode

4. Filter and Map 

result = list(map(lambda x: x*2, filter(lambda x: x > 0, numbers)))
Enter fullscreen mode Exit fullscreen mode

5. Sort by Key 

sorted_list = sorted(data, key=lambda x: x['name'])
Enter fullscreen mode Exit fullscreen mode

6. Matrix Transpose 

transposed = list(zip(*matrix))
Enter fullscreen mode Exit fullscreen mode

7. Unique Elements 

unique = list(set(my_list))
Enter fullscreen mode Exit fullscreen mode

8. File Read 

lines = open('file.txt').read().splitlines()
Enter fullscreen mode Exit fullscreen mode

9. Chunk List 

chunks = [lst[i:i+n] for i in range(0, len(lst), n)]
Enter fullscreen mode Exit fullscreen mode

10. Deep Flatten 

def flatten(lst):
    return [x for item in lst for x in (flatten(item) if isinstance(item, list) else [item])]
Enter fullscreen mode Exit fullscreen mode

More Python tools at https://create-openings-unsigned-garden.trycloudflare.com.

🔧 Ready to Use These Tools?

Don't build from scratch — I've packaged these solutions (and 390+ more) as ready-to-run Python tools.

🛒 Browse Anna's Digital Products

  • ✅ Tested & verified code
  • âš¡ Instant delivery via crypto (BTC/XMR)
  • 💰 Starting at $25
  • 🔧 Python tools, bots, scrapers & automation

Pay with Bitcoin or Monero. Instant download after confirmation.

Get the Full Code

Want the complete working system? I've packaged 400+ production-ready Python automation tools, each with full source code, documentation, and instant crypto delivery.

Browse the collection: https://petroleum-board-hawaii-lol.trycloudflare.com

What's included:

  • 400+ Python scripts — browser automation, crypto payments, web scraping, bots, and more
  • Instant delivery — pay with Bitcoin/Monero, receive download link immediately
  • Full source code — not snippets, complete working tools you can run today
  • Free updates — buy once, get all future additions

Featured products:

Each tool has a live code preview on the store — see exactly what you're buying before you pay.

Top comments (0)