Alex Spinov

Posted on Mar 25

Python One-Liners That Save Me Hours Every Week

#python #tutorial #beginners #productivity

Tiny Scripts, Big Time Savings

These are the Python one-liners I actually use in production — not clever tricks for interviews, but practical shortcuts that save real time.

File Operations

# Read entire file
content = open("data.txt").read()

# Read lines into list (stripped)
lines = [l.strip() for l in open("data.txt")]

# Write list to file
open("output.txt", "w").write("\n".join(lines))

# Count lines in a file
line_count = sum(1 for _ in open("huge_file.log"))

# Find all .py files recursively
from pathlib import Path
py_files = list(Path(".").rglob("*.py"))

Data Processing

# CSV to list of dicts
import csv
data = list(csv.DictReader(open("data.csv")))

# JSON file to dict
import json
config = json.loads(open("config.json").read())

# Flatten nested list
flat = [x for sublist in nested for x in sublist]

# Remove duplicates preserving order
unique = list(dict.fromkeys(items))

# Group items
from itertools import groupby
groups = {k: list(v) for k, v in groupby(sorted(items, key=key_fn), key=key_fn)}

Web Requests

# Quick GET request
import requests
data = requests.get("https://api.openalex.org/works?search=python&per_page=3").json()

# Download a file
open("file.zip", "wb").write(requests.get("https://example.com/file.zip").content)

# Check if URL is alive
is_alive = requests.head("https://example.com", timeout=5).status_code == 200

String Processing

# Extract emails from text
import re
emails = re.findall(r"[\w.+-]+@[\w-]+\.[\w.]+", text)

# Extract URLs from text
urls = re.findall(r"https?://[\S]+", text)

# Clean whitespace
clean = " ".join(text.split())

# Title case
title = "hello world from python".title()  # "Hello World From Python"

# Reverse a string
reversed_str = text[::-1]

System & CLI

# Quick HTTP server (run from terminal)
# python3 -m http.server 8000

# Quick JSON formatting
# echo '{"a":1}' | python3 -m json.tool

# Get current timestamp
from datetime import datetime
now = datetime.now().isoformat()

# Timer decorator
import time
timer = lambda f: lambda *a, **k: (t := time.time(), r := f(*a, **k), print(f"{f.__name__}: {time.time()-t:.2f}s"))[1]

Data Analysis (with DuckDB)

# Query CSV with SQL — one line
import duckdb
result = duckdb.sql("SELECT category, COUNT(*) FROM 'sales.csv' GROUP BY 1 ORDER BY 2 DESC").df()

# Quick stats
stats = duckdb.sql("SELECT COUNT(*), AVG(price), MIN(price), MAX(price) FROM 'products.csv'").fetchone()

API Calls

# Search academic papers (no key needed)
papers = requests.get("https://api.openalex.org/works", params={"search": "AI", "per_page": 5}).json()["results"]

# Get weather (no key needed)
weather = requests.get("https://api.open-meteo.com/v1/forecast", params={"latitude": 40.71, "longitude": -74.01, "current_weather": True}).json()["current_weather"]

# Get exchange rate (no key needed)
rate = requests.get("https://open.er-api.com/v6/latest/USD").json()["rates"]["EUR"]

The Pattern

Every one-liner follows the same principle: import → call → result in one expression.

No boilerplate. No classes. No 50 lines of setup for a simple task.

When it gets complex, I move to a proper script. But for quick tasks? These save me hours every week.

All My Scripts

I maintain a collection of ready-to-run Python scripts:

python-data-scripts — 10+ scripts for APIs, scraping, and data processing.

What Python one-liners do you use daily? Share your favorites — I'll add the best ones to the collection.

I write about practical Python and free APIs. Follow for more.

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