Reference library

Python Code Samples

Medium snippets you can copy, study, and run in the browser editor.

8 matches
Files & data medium

How to Find Duplicate Files by Size and Hash in Python

Recursively scan a directory, group files by size, then hash candidates to identify exact duplicate files.

deduplication filesystem hashlib
Python
import hashlib
from pathlib import Path

def hash_file(path, chunk_size=8192):
    hasher = hashlib.md5()
    with open(path, 'rb') as f:
        while chunk := f.read(chunk_size):
            hasher.update(chunk)
    return hasher.hexdigest()

def find_duplicates(directory):
    size_map = {}
    for path in Path(dir…
17 0 Open
Algorithms & data structures medium

Find Missing Numbers, Duplicates, and Ranges in Python

Analyze a list to identify missing numbers, duplicate values, and contiguous ranges using sets and the Counter class.

algorithms sets counting
Python
def find_missing_duplicates_ranges(numbers):
    """Find missing numbers, duplicates, and ranges in a list."""
    from collections import Counter
    
    if not numbers:
        return {"missing": [], "duplicates": [], "ranges": []}
    
    full_range = set(range(min(numbers), max(numbers) + 1))
    present = set(n…
13 0 Open
Algorithms & data structures medium

How to Find Four Sum Quadruplets in Python (Sorted Demo)

Find all unique quadruplets in a sorted array that sum to a target, with duplicate skipping.

two-pointers sorting four-sum
Python
def four_sum(nums, target):
    nums.sort()
    result = []
    n = len(nums)

    for i in range(n - 3):
        if i > 0 and nums[i] == nums[i - 1]:
            continue
        for j in range(i + 1, n - 2):
            if j > i + 1 and nums[j] == nums[j - 1]:
                continue
            left, right = j + 1…
13 0 Open
Automation & scripting medium

Find and Delete Duplicate Files Using Hashing in Python

Walk a directory tree, compute SHA256 hashes for every file, and delete duplicates that share the same hash.

deduplication files hashing
Python
import hashlib
import os
from pathlib import Path

def file_hash(path, block_size=65536):
    """Return SHA256 hash of file content."""
    hasher = hashlib.sha256()
    with open(path, 'rb') as f:
        while chunk := f.read(block_size):
            hasher.update(chunk)
    return hasher.hexdigest()

def find_and_d…
51 0 Open
Data pipelines & processing medium

Build a Python Utility That Detects Duplicate Records Across Multiple Excel Sheets

A Python utility that uses pandas to find overlapping records across different Excel sheets based on specified key columns.

pandas excel data cleaning
Python
import pandas as pd
from pathlib import Path

def find_duplicate_records_across_sheets(file_path: str, key_columns: list, sheet_names: list) -> dict:
    """
    Detect duplicate records across multiple Excel sheets based on specified key columns.
    
    Args:
        file_path: Path to the Excel file
        key_co…
47 0 Open
System design patterns medium

Inbox pattern consumer dedupe mock in Python

Implements a mock inbox consumer that deduplicates incoming messages by ID, with automatic eviction of old seen IDs to prevent unbounded memory growth.

deduplication inbox-pattern dataclasses
Python
import json
from collections import deque
from dataclasses import dataclass, field
from hashlib import sha256
from typing import Any


@dataclass
class InboxConsumer:
    max_seen: int = 1000
    seen_ids: set = field(default_factory=set)
    seen_history: deque = field(default_factory=deque)

    def _mark_seen(self,…
13 0 Open
API design & gRPC medium

How to Build an Idempotency-Key POST Handler in Python

Python HTTP server mock that accepts POST requests and deduplicates them using an Idempotency-Key header, returning the same response for repeated calls.

http-server idempotency api-mock
Python
import hashlib
import json
from http.server import BaseHTTPRequestHandler, HTTPServer
from urllib.parse import urlparse


class MockAPI(BaseHTTPRequestHandler):
    responses = {}

    def do_POST(self):
        length = int(self.headers.get("Content-Length", 0))
        body = self.rfile.read(length).decode("utf-8")
…
14 0 Open
Reliability & rate limiting medium

At Least Once with Idempotent Consumer in Python

Implements a thread-safe idempotent consumer that processes each unique message exactly once, even when a producer sends duplicates under an at-least-once delivery model.

idempotency at-least-once threading
Python
import threading
import time
import uuid
from collections import Counter


class IdempotentConsumer:
    def __init__(self):
        self.processed = set()
        self._lock = threading.Lock()

    def consume(self, message_id, payload):
        with self._lock:
            if message_id in self.processed:
          …
16 0 Open

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