Friends Don’t Let Friends Write Mediocre Code

Pragmatic Mindset¶

/praɡˈmatɪk/ adjective - dealing with things sensibly and realistically in a way that is based on practical rather than theoretical considerations. - Oxford’s Google Dictionary

Mediocre code sucks, I’ve been there. I’ve written it. I’ve reviewed worse. Picture a chump-me-hammering out scripts with no tests, pip install chaos, and prayers to the gods of bytes it’d run on someone else’s machine. The journey to pragmatism? It is me, fed up with endless rewrites, saying ‘no more.’

Mediocre code is not GPT-3.5’s vibe-salad disaster, it is just code I can not stand. Yeah, I said it. My case for pragmatism is here to make you hate it too. It’s okay to disagree; in fact, I expect you to in some cases. It means you’re pragmatic after all.

This book is meant to drag mediocre code into the light, showing you a path from mediocrity to pragmatism through Terrible, Better, and Pragmatic. It draws on lessons learned from hours spent reading, writing, debugging, reviewing, experimenting, and making dozens of mistakes while building Python solutions.

Example I: OOP to functional to nothing. Sometimes, no code is the best code.

from pathlib import Path


class DataLoader:
   def __init__(self, file_path: Path) -> None:
       self.file_path = file_path

   def load(self) -> str:
       with open(self.file_path, "r") as file:
           return file.read()


def main() -> None:
   file_path = Path("README.md")
   loader = DataLoader(file_path)
   data = loader.load()
   print(data)


if __name__ == "__main__":
   main()

from pathlib import Path


def load(file_path: Path) -> str:
   with open(file_path, "r") as file:
       return file.read()


def main() -> None:
   file_path = Path("README.md")
   data = load(file_path)
   print(data)


if __name__ == "__main__":
   main()

from pathlib import Path


def main() -> None:
   file_path = Path("README.md")
   data: str = file_path.read_text()
   print(data)


if __name__ == "__main__":
   main()

Example II: Take word-counting: I used to cobble together if-else messes, reinventing the wheel like a rookie. Then I stumbled on stdlib defaultdict, simpler, less embarrassing, but still yet not pragmatic. Enter Counter: one clean stdlib line that does it right. It’s not about being clever, it’s about being simple. Master stdlib, and you’ll stop writing junk.

from typing import Iterable 


def get_word_counts(words: Iterable[str]) -> dict[str, int]:
   word_counts = {}

   for word in words: 
       if word in word_counts:
           word_counts[word] += 1
       else:
           word_counts[word] = 1
   
   return word_counts


if __name__ == "__main__":
   from pathlib import Path

   words = iter(Path("README.md").read_text().lower().split())
   print(get_word_counts(words=words))

from collections import defaultdict
from typing import Iterable 


def get_word_counts(words: Iterable[str]) -> dict[str, int]:
   word_counts = defaultdict(int)

   for word in words:
       word_counts[word] += 1

   return dict(word_counts)


if __name__ == "__main__":
   from pathlib import Path

   words = iter(Path("README.md").read_text().lower().split())
   print(get_word_counts(words=words))

from collections import Counter
from typing import Iterable 


def get_word_counts(words: Iterable[str]) -> dict[str, int]:
   word_counts = Counter(words)

   return dict(word_counts)


if __name__ == "__main__":
   from pathlib import Path

   words = iter(Path("README.md").read_text().lower().split())
   print(get_word_counts(words=words))

We can write Python code in a thousand ways -OOP, functional, or what have you. A pragmatic mindset says, I don’t care about the paradigm fetish. I care about code that works, changes without a meltdown, and doesn’t make onboarding a nightmare. If I can’t understand and test it in ten minutes, it’s trash.

Are You Still My Friend?¶

So, you’re pragmatic, eh? Then you are still my friend. Pragmatic Python is a book my alter-ego always wanted to write to my democratic self. It is fiercely opinionated way to programming with Python. It is a way for a friend, an opinonated one, who don’t let friends write mediocre code.

Who I am? Your Friend, Silly.¶

I’m Prayson Wilfred Daniel, Principal Data Scientist at _42, and I’ve written mediocre code. I got sick of rewrites, so I flipped the script. Now, I build solutions that suck-less: community-driven and design patterns-ish that make code easy to change, test, and onboard. CI/CD testing? Mandatory, I have been tested. This is my Arrange, Act, and Assert book.

I ditched pandas bloat for polars, requests for httpx, unittest for pytest. Legacy’s dead; uv and ruff run my show. This book’s my alter-ego’s fight, pragmatic, no-BS code that works. Friends don’t let friends settle for less.

I bring a hefty dose of Danish sarcasm to the table and don’t take everything too seriously, because, let’s be real, religiously following ideas, best practices, design patterns or rules is a total buzzkill (and frankly anti-pragmatic).