Chapter 13: Python Foundations
Python is one of the most readable programming languages ever written. That is not an accident. Its creator, Guido van Rossum, designed it in the early 1990s with one strong opinion: code is read far more often than it is written, so readability should come first. The result is a language that looks almost like plain English, where the structure of a program is visible at a glance.
Chapter 14: Dictionaries & String Handling
In Chapter 13, a variable held one value. That is fine for a single piece of information, but real data is never a single piece. A user has a name, an email, a plan, and a status. A server has a hostname, a port, a region, and an uptime. When those pieces belong together, you want to store them together — not scattered across four separate variables with no connection between them.
Chapter 15: Functions, Loops & OOP
Write the same block of code in three places and you have a problem. Change one, forget to change the others, and your program gives three different answers for the same question. The solution is a function — write the logic once, give it a name, and call it wherever you need it.