Reference library

Python Code Samples

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

3 matches
Algorithms & data structures easy

Segregate Negative Numbers Before Positives in Python

Reorders a list so all negative numbers appear before non-negative numbers while preserving the original relative order of elements.

lists partition stability
Python
def segregate_negatives(numbers):
    """Segregate negatives before positives without altering relative order."""
    negatives = [n for n in numbers if n < 0]
    positives = [n for n in numbers if n >= 0]
    return negatives + positives


if __name__ == "__main__":
    sample = [3, -1, 4, -5, 2, -9, 0]
    result =…
14 0 Open
Testing & modern typing easy

Dependency Injection in Python for Testability

Inject a config dependency into a service so you can swap a real environment-based config for a fake one in tests.

dependency-injection testing mocking
Python
import os


class Config:
    """Simple config loader that can be easily faked in tests."""
    def get(self, key, default=None):
        return os.environ.get(key, default)


class UserService:
    def __init__(self, config):
        self.config = config

    def get_timeout(self):
        return int(self.config.get(…
16 0 Open
ML engineering pipelines medium

How to Detect Data Drift with PSI in Python

Calculate the Population Stability Index (PSI) in Python to compare expected vs actual distributions and detect data drift in machine learning pipelines.

data drift psi monitoring
Python
import numpy as np

def calculate_psi(expected, actual, buckets=10):
    """Calculate Population Stability Index (PSI) between two distributions."""
    # Create bucket edges based on expected distribution percentiles
    edges = np.percentile(expected, np.linspace(0, 100, buckets + 1))
    edges[-1] = np.inf  # Ensur…
13 0 Open

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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.