Hey, I’m Nitin 👋

You think dictionary lookup is always O(1). That’s only half the story. Today, you understand how dictionaries actually work. Today’s Goal By the end of today, you will: Understand how dictionaries store data Learn how hashing works Understand collisions and their impact Know when O(1) breaks down The Illusion user = { "name": "John", "age": 30 } You think: This is just key-value storage Reality: This is a highly optimized hash table Dictionary Internal Model key -> hash(key) -> index -> slot -> value Dictionary does NOT scan all keys. It jumps directly using hash. ...

You think a list is just a collection of items. It is not. It is a memory-managed structure with real trade-offs. Today, you stop using data structures blindly. Today’s Goal By the end of today, you will: Understand how lists, tuples, and sets work internally Learn time and space complexity Choose the right structure based on behavior and cost The Illusion data = [1, 2, 3] You think this stores values. Reality: [ ptr | ptr | ptr ] -> references to objects A list stores references, not values. ...

If you think x = 10 means “x stores 10”… you are already misunderstanding Python. Today, we fix that. Today’s Goal By the end of today, you will: Understand how Python stores data in memory Learn references vs values Understand mutability Avoid hidden bugs The Illusion You write: x = 10 y = x You think: x and y both store 10 Wrong. What Actually Happens Memory: [10] ← object x ─────┐ ├──→ [10] y ─────┘ Variables do not store values. They store references to objects. ...

You write Python. But Python is not executing your code the way you think. Today, you stop treating Python as magic. Today’s Goal By the end of today, you will: Understand how Python executes your code Learn what happens between .py to execution Build a mental model of the Python interpreter The Illusion You write: x = 10 y = x + 5 print(y) You assume: Python reads this line by line and runs it That assumption is wrong. ...