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Python Code Samples

Copy-ready Python snippets by topic and difficulty — short, focused, and runnable in the browser editor.

3 matches
Files & data medium

How to Atomically Write Files in Python with Temp File and Rename

Write a file atomically using a temporary file and os.replace so readers never see partial writes even if the process crashes mid-write.

atomic-write tempfile fsync
Python 
import os
import tempfile
from pathlib import Path

def atomic_write(path: str | Path, content: str) -> None:
    """Write content to path atomically using a temp file and rename."""
    path = Path(path)
    path.parent.mkdir(parents=True, exist_ok=True)

    fd, temp_path = tempfile.mkstemp(
        dir=str(path.par…
17 0 Open
Files & data medium

How to Write a List of Lines to a Text File Safely in Python

This code atomically writes a list of strings as lines to a text file using a temporary file and os.replace to prevent corruption.

files atomic-write pathlib
Python 
from pathlib import Path
import tempfile
import os

def write_lines_safely(lines: list[str], filepath: str | Path) -> None:
    """Write lines to a text file atomically to avoid corruption."""
    path = Path(filepath)
    path.parent.mkdir(parents=True, exist_ok=True)
    
    fd, temp_path = tempfile.mkstemp(dir=str…
13 0 Open
Database scaling & optimization easy

Simulate PostgreSQL Vacuum to Reclaim Space in Python

A Python class that safely rewrites a data file to remove deleted rows and reclaim physical space, mimicking PostgreSQL's VACUUM operation.

vacuum file-management database
Python 
import shutil
import os

class VacuumCleaner:
    """Simulates PostgreSQL-style vacuum reclaiming dead space in a file."""
    
    def __init__(self, filepath, fill_ratio=0.7, dead_marker="[DELETED]"):
        self.filepath = filepath
        self.fill_ratio = fill_ratio
        self.dead_marker = dead_marker
    
  …
13 0 Open

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Copy-ready Python snippets for learners and developers

PythonSkillset code samples are short, focused examples organised by topic and difficulty. Every snippet is server-rendered HTML — readable by search engines and easy to copy. Open any sample, read the notes, copy the code, then press Try in editor to run it in the browser with Pyodide.

How to use this library

  1. Pick a topic section — strings, lists, files, functions, and more
  2. Open a sample, read How it works, and copy the code block
  3. Run it in the IDE, tweak values, then take a related quiz or tutorial lesson

Samples vs tutorials and challenges

Samples are quick reference — one concept per page. For step-by-step teaching, use our Python tutorials. To test yourself, try quizzes or coding challenges. Clean up style with the Python formatter.

Related coding tools

Free online Python IDE Write and run Python in your browser — no install. Free Python code formatter Format with autopep8 — side-by-side PEP 8 cleanup.