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How to Detect Expired Domains Using Python
Parse a list of domain registration data and compare expiry dates to today to find expired domains.
import datetime
# List of test domains with fake registration and expiry dates
# Format: (domain, registration_date, expiry_date)
test_domains = [
('example.com', '2020-01-15', '2024-01-15'), # Expired
('google.com', '1997-09-15', '2026-09-15'), # Still active
('test-site.org', '2019-06-01', '2023-06-0…Find Most Active Contributors in a Repository with Python
Filter recent commits by date and count the most active contributors using Counter and datetime.
from collections import Counter
from datetime import datetime, timedelta
# Simulated commit data
commits = [
{"author": "Alice", "timestamp": datetime.now() - timedelta(days=1)},
{"author": "Bob", "timestamp": datetime.now() - timedelta(days=2)},
{"author": "Alice", "timestamp": datetime.now() - timedelta…Calculate Time Difference Across Time Zones in Python
Compute the current time difference in hours between two time zones given their UTC offsets using Python's datetime and timezone modules.
from datetime import datetime, timezone, timedelta
def time_difference(from_tz_offset, to_tz_offset):
"""
Calculate time difference in hours between two time zones given their offsets from UTC.
Offsets are in hours (e.g., -5 for EST, +5.5 for IST).
"""
tz1 = timezone(timedelta(hours=from_tz_offset…How to Archive Old Files by Age in Python
Move files older than a specified number of days from a source directory to an archive directory using Python's pathlib and shutil modules.
import os
import shutil
import time
from pathlib import Path
def archive_old_files(source_dir: str, archive_dir: str, days_old: int) -> None:
cutoff_time = time.time() - (days_old * 86400) # 86400 seconds in a day
archive_path = Path(archive_dir)
archive_path.mkdir(parents=True, exist_ok=True)
for i…How to Build a Dated Backup Filename with Timestamp in Python
Generate unique backup filenames with a timestamp using Python's datetime module and f-strings.
from datetime import datetime
def build_backup_filename(base_name: str, extension: str = "bak") -> str:
"""Generate a dated backup filename with timestamp."""
timestamp = datetime.now().strftime("%Y%m%d_%H%M%S")
return f"{base_name}_{timestamp}.{extension}"
if __name__ == "__main__":
backup_file = bu…Serialize Python dict to JSON with custom default for datetime
Convert a Python dict containing datetime and set objects into JSON by providing a custom default serializer.
import json
from datetime import datetime
def custom_serializer(obj):
if isinstance(obj, datetime):
return obj.isoformat()
if isinstance(obj, set):
return list(obj)
return str(obj)
data = {
"name": "Alice",
"created_at": datetime(2024, 3, 15, 10, 30, 45),
"tags": {"python", "j…Aggregate Log Errors Count by Hour in Python
Counts ERROR log lines per hour using regex and Counter, returning a sorted dictionary of hourly totals.
import re
from collections import Counter
from datetime import datetime
def aggregate_errors_by_hour(log_lines):
pattern = re.compile(r'^(\d{4}-\d{2}-\d{2} \d{2}):\d{2}:\d{2}.*ERROR')
hourly_counts = Counter()
for line in log_lines:
match = pattern.match(line)
if match:
ho…Build a Live Countdown Timer for Events in Python
A Python script that displays a real-time countdown to a target date and time, updating every second in the console.
import datetime
import time
def countdown(event_name, target_datetime):
"""Displays a live countdown to a target datetime."""
while True:
now = datetime.datetime.now()
remaining = target_datetime - now
if remaining.total_seconds() <= 0:
print(f"\n🚀 {event_name} is happening…How to Backup an SQLite Database with a Timestamp in Python
Backs up an SQLite database file to a timestamped copy using the sqlite3 backup API.
import sqlite3
import shutil
from datetime import datetime
from pathlib import Path
def backup_database(db_path: str, backup_dir: str = "backups") -> Path:
db = Path(db_path)
backup_folder = Path(backup_dir)
backup_folder.mkdir(exist_ok=True)
timestamp = datetime.now().strftime("%Y%m%d_%H%M%S")
…How to Filter Docker Containers for Pruning in Python
Simulate Docker's container prune by filtering a JSON list for exited containers older than a cutoff, returning pruned IDs and space freed.
import json
from datetime import datetime, timedelta
def parse_docker_ps(json_output: str, older_than_hours: int = 24) -> list:
containers = json.loads(json_output)
cutoff = datetime.now() - timedelta(hours=older_than_hours)
return [
c for c in containers
if datetime.fromisoformat(c["crea…How to Find Stale GitHub Issues in Python
Filter a list of GitHub issues to find those not updated within a configurable number of days using Python datetime arithmetic.
import os
from datetime import datetime, timezone, timedelta
import re
# Simulated GitHub issue data structure
SAMPLE_ISSUES = [
{"number": 101, "title": "Login button not working", "updated_at": "2025-06-01T12:00:00Z", "assignee": "alice"},
{"number": 102, "title": "Fix database migration error", "updated_at…Parse WHOIS Data with Python Regex
Extract domain registration fields from a mock WHOIS record using regex and compute days until expiration.
import re
from datetime import datetime
def parse_whois(whois_text: str) -> dict:
"""Extract key registration fields from a mock WHOIS record."""
patterns = {
"domain": r"Domain Name:\s*(.+)",
"registrar": r"Registrar:\s*(.+)",
"creation_date": r"Creation Date:\s*(.+)",
"expir…Parse cron expression and compute next run datetime in Python
Parse a 5-field cron expression and compute the next matching datetime starting from a given base time.
from datetime import datetime, timedelta
import re
def parse_cron_and_next_run(cron_expr, base_time=None):
"""Parse a cron expression and compute the next run time."""
if base_time is None:
base_time = datetime.now().replace(second=0, microsecond=0)
fields = cron_expr.split()
if len(fields) !…Group Python Events into Sessions with a Gap Timeout
Groups timestamped events into sessions, starting a new session when the time gap exceeds a specified timeout.
from itertools import groupby
from datetime import datetime, timedelta
def session_window_group(events, gap_seconds=300):
"""Group events into sessions where gap > gap_seconds starts a new session."""
if not events:
return []
events = sorted(events, key=lambda x: x[0])
sessions = []
c…How to Convert Data Types in a Python Data Pipeline
Demonstrates a simple Python data pipeline that converts string values to proper types (bool, int, float, datetime) and outputs structured JSON.
import json
from datetime import datetime
def convert_value(value):
"""Convert string values to appropriate Python types."""
if value.lower() == "true":
return True
if value.lower() == "false":
return False
if value.isdigit():
return int(value)
try:
return float(val…How to Parse Data in Python: A Beginner's Helper
This helper parses a JSON payload, extracts user names, emails, and signup dates, then summarizes the results.
import json
from datetime import datetime
from typing import Dict, List
def parse_data(payload: str) -> Dict[str, List]:
"""Parse a JSON payload and extract useful fields."""
raw = json.loads(payload)
users = raw.get("users", [])
parsed = {
"names": [],
"emails": [],
"signup_…Rollback dataset to previous snapshot pointer in Python
A SnapshotManager class stores timestamped data snapshots and rolls back to the most recent snapshot at or before a target time.
from datetime import datetime, timedelta
class SnapshotManager:
def __init__(self):
self.snapshots = {} # timestamp -> data
self.current_pointer = None
def create_snapshot(self, data):
timestamp = datetime.now()
self.snapshots[timestamp] = data
self.current_pointer =…Mock ECS Task Run Stop Status Dict in Python
Build a mock ECS task status dictionary with RUNNING/STOPPED states using the standard library.
from datetime import datetime, timezone
def mock_ecs_task_status(task_id: str, state: str = "RUNNING") -> dict:
"""Return a mock ECS task status dictionary."""
return {
"taskArn": f"arn:aws:ecs:us-east-1:123456789012:task/cluster/{task_id}",
"taskDefinition": "arn:aws:ecs:us-east-1:1234567890…Data Conversion Helper Functions in Python
A set of beginner-friendly helper functions to convert between JSON strings and Python data, parse dates, and read/write files using pathlib.
from datetime import datetime
from pathlib import Path
import json
def to_json(data, indent=2):
"""Convert Python data to pretty-printed JSON string."""
return json.dumps(data, indent=indent, default=str)
def from_json(json_string):
"""Parse JSON string back into Python data."""
return json.loads(jso…How to Format Data with Python's datetime and JSON Helpers
A beginner-friendly set of helper functions to format dates and safely read/write JSON files in Python.
from datetime import datetime
from pathlib import Path
import json
def format_today(pattern: str = "%Y-%m-%d") -> str:
"""Return today's date formatted with the given pattern."""
return datetime.now().strftime(pattern)
def load_json(file_path: str) -> dict:
"""Read and parse a JSON file safely."""
…How to freeze time in Python tests with freezegun
Use the freezegun decorator to freeze datetime.now() at a fixed timestamp so tests that depend on current time run deterministically.
from datetime import datetime
from freezegun import freeze_time
@freeze_time("2024-01-15 12:30:00")
def test_frozen_time():
now = datetime.now()
return now
if __name__ == "__main__":
result = test_frozen_time()
print(result)Mock datetime with time-machine in Python
Use the time-machine library to travel to a fixed datetime when running tests or scripts, mocking datetime.utcnow().
from time_machine import travel
from datetime import datetime
@travel("2020-01-01 10:30:00")
def check_date():
return datetime.utcnow()
if __name__ == "__main__":
print(check_date())Mock datetime.now to freeze time in Python
Use unittest.mock.patch to replace datetime.now with a fixed value so your code always sees the same time during tests.
from datetime import datetime
from unittest.mock import patch
def current_message():
now = datetime.now()
return f"Current time: {now:%Y-%m-%d %H:%M:%S}"
if __name__ == "__main__":
with patch("__main__.datetime") as mock_dt:
mock_dt.now.return_value = datetime(2024, 3, 15, 10, 30, 0)
prin…How to Serialize and Deserialize JSON Event Payloads in Python
Define an EventPayload class with custom to_json and from_json methods to convert event objects to JSON strings and back, using datetime parsing.
import json
from datetime import datetime
class EventPayload:
def __init__(self, event_id, event_type, timestamp, data):
self.event_id = event_id
self.event_type = event_type
self.timestamp = timestamp
self.data = data
def to_json(self):
return json.dumps({
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