Author: alerainfotech

Amazon’s data services form a powerful ecosystem for building scalable, serverless data lakes and warehouses. This guide explains the complete picture: from S3 to Glue to Athena and Redshift. You’ll learn what each component does, why it exists, when to use it, and how they work together. 🔹 Part 1: What Is Amazon S3? Amazon…

Python’s coroutines let you write concurrent, non-blocking code that’s readable, powerful, and fast. They’re especially helpful when you’re dealing with I/O operations like web requests or file access. But coroutines can be confusing — especially when you’re wondering:“If a coroutine gives up control using await, how does it ever finish its job?” Let’s explore all this in depth. 🔍 What…

When you start diving deeper into Python classes, you’ll likely come across strange-looking method names like __str__, __repr__, or __len__. These are dunder methods (short for “double underscore”), and they power many of Python’s built-in behaviors. But they also raise some excellent questions: This article brings clarity to all of these with clean examples and explanations. 1. Why Python Uses __str__() Instead…

One of Python’s most flexible and readable features is its support for variable-length arguments using *args and **kwargs. But if you’ve ever wondered: You’re in the right place. This guide explains it all, with clear examples, visual breakdowns, and pro tips for interviews and real-world use. 🧠 What Are *args and **kwargs? Syntax Name Accepts *args Positional arguments A tuple of unnamed values…

One of the most beautiful things about Python is the expressive, readable syntax it offers — especially in the form of list comprehensions and generator expressions. But behind the elegance lies some subtle performance and behavior differences that often come up in interviews and production code. This post explains: 🔷 What Is a List Comprehension? A list comprehension is a…

If you’re coming from Java, C++, or C#, one of the first things you’ll notice in Python is this: “Wait… how can I define def price(self) and def price(self, value) in the same class? Isn’t that illegal?” Yes — in Java, that’s method overloading.But in Python? Well… it depends. In this article, we’ll walk through: 🔍 Let’s Start with the Problem…

If you come from languages like Java, C++, or C#, you’re used to having strict access control: private, protected, public. But in Python, you might be surprised to find that private variables aren’t truly private. In this article, we’ll break down: ❓ Does Python Have Private Attributes? Short answer: No, not really. Python does not have real access modifiers…

Whether you’re preparing for interviews or building real-world systems, mastering the deque data structure and the sliding window technique will help you solve a class of problems quickly and efficiently. This post will walk you through: 🔷 What is deque? deque stands for double-ended queue, and it lives in Python’s collections module. It allows: ✅ Import and usage: from collections import dequedq = deque()dq.append(1)…

When solving problems like “find the top K largest elements”, you have two common strategies: At first glance, it may seem both approaches are similar — especially since we’re just storing K elements — but their performance and behavior differ significantly. 🔍 Scenario: Maintain Top 3 Elements Say you’re scanning a list or stream of numbers like this:…