Reference library

Python Code Samples

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

3 matches
Data pipelines & processing easy

Attach Source File Metadata to Records in Python

Add a source filename field to each record in a list by merging a new key into every dictionary using a dict unpacking comprehension.

lineage metadata dict-unpacking
Python 
from pathlib import Path
import json

def attach_source_metadata(records, source_file):
    """Attach source filename metadata to each record."""
    return [
        {**record, "source": Path(source_file).name}
        for record in records
    ]

if __name__ == "__main__":
    source = "/data/raw/customers.csv"
    …
15 0 Open
Big data & Spark easy

How to Truncate Lineage Back to a Checkpoint in Python

Walks a linked list of lineage nodes upward to find the nearest checkpoint and returns that node, truncating the lineage.

lineage checkpoint linked-list
Python 
class LineageNode:
    def __init__(self, name, parent=None, checkpoint=None):
        self.name = name
        self.parent = parent
        self.checkpoint = checkpoint

    def truncate_at_checkpoint(self):
        """Truncate lineage back to the last checkpoint."""
        current = self
        while current.check…
16 0 Open
Big data & Spark medium

Lazy Evaluation Transform Lineage Mock in Python

Build a mock lineage tracker for data transforms using lazy evaluation and function wrappers in Python.

lazy-evaluation lineage decorator
Python 
import functools


def lazy_transform(pipeline):
    """Build a mock lineage tracker using lazy evaluation."""
    lineage = []

    def wrap(func):
        @functools.wraps(func)
        def wrapper(*args, **kwargs):
            result = func(*args, **kwargs)
            lineage.append({"transform": func.__name__, "a…
16 0 Open

Browse by section

Each section groups closely related Python snippets.

Guide: free Python code samples library

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.