Python code explainers

python

import re
from collections import Counter
from pathlib import Path

Ranking the top words in a PDF

text-processing regex counting

Intermediate 6 steps

python

import django_filters
from django import forms
from django.utils import timezone

Building a date-range FilterSet in Django

filtering querysets form-widgets

Intermediate 6 steps

python

import json
import hashlib
from datetime import timedelta

Idempotent payment endpoints in FastAPI

idempotency redis distributed-locking

Advanced 9 steps

python

from flask import Blueprint, jsonify, request, abort
 
v1 = Blueprint("users_v1", __name__)
v2 = Blueprint("users_v2", __name__)

Versioning a Flask API with Blueprints

api versioning blueprints rest

Intermediate 7 steps

python

import time
import threading
from enum import Enum
from functools import wraps

Building a circuit breaker in Python

circuit-breaker resilience decorators

Advanced 7 steps

python

from django.contrib.postgres.search import SearchQuery, SearchRank, SearchVector
from django.core.cache import cache
from django.db.models import F
from django.http import JsonResponse

Ranked full-text search in Django

full-text-search debouncing caching

Advanced 9 steps

python

import os
from datetime import timedelta

Class-based config in a Flask app factory

configuration app-factory inheritance

Intermediate 7 steps

python

import time
 
from flask import Flask, g, request

Timing requests with Flask hooks

middleware request-lifecycle instrumentation

Intermediate 5 steps

python

from pathlib import Path
 
from PIL import Image, ImageOps

Batch image resizing with Pillow

image-processing batch-jobs error-handling

Intermediate 8 steps

python

import base64
import hashlib
import hmac
import json

Building signed expiring tokens with HMAC

hmac authentication base64

Intermediate 7 steps

python

from decimal import Decimal, ROUND_HALF_UP
 
from babel.numbers import format_currency
from flask import Flask

Building a currency Jinja filter in Flask

template filters decimal precision internationalization

Intermediate 6 steps

python

from functools import wraps
 
import jwt
from flask import current_app, g, jsonify, request

How a JWT auth decorator works in Flask

decorators authentication jwt

Intermediate 6 steps

python

from django.contrib import admin
from django.utils import timezone
from django.utils.html import format_html

Custom columns in the Django admin

admin-customization computed-columns html-rendering

Intermediate 7 steps

python

from collections import defaultdict
from datetime import datetime
from openpyxl import load_workbook

Summarizing an Excel sheet with openpyxl

excel-parsing aggregation type-dispatch

Intermediate 7 steps

python

from django.contrib.auth.mixins import LoginRequiredMixin
from django.views.generic import ListView
 
from .models import Invoice

Building a scoped, filtered ListView in Django

class-based views queryset filtering authentication

Intermediate 7 steps

python

import click
 
 
@click.command()

Building a typed CLI with Click

cli decorators validation

Intermediate 7 steps

python

import csv
 
from django.http import StreamingHttpResponse
from django.utils.timezone import now

Streaming a CSV export in Django

streaming csv-export generators

Intermediate 7 steps

python

from pathlib import Path
 
import chardet

Reading text files of unknown encoding in Python

encoding byte-order-mark fallback

Intermediate 8 steps