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Chapter 16: Strings and Type Casting

Text is everywhere in programming. User input, error messages, file names, web content, chat messages—all are strings. In this chapter, you'll learn how to create, manipulate, and validate text data using Python's powerful string capabilities.

You'll also learn type casting—how to safely convert between different data types. Need to turn user input (always a string) into a number for calculations? Need to display a calculation result as formatted text? Type casting is the bridge between different data representations.

By the end of this chapter, you'll be able to process text confidently and convert between types safely—two essential skills for building interactive programs.

What You'll Learn​

In this chapter, you'll master:

String Fundamentals and Operations​

  • Lesson 1: String Fundamentals — Understand what strings are, how to create them, and why they're immutable
  • Lesson 2: Essential String Methods — Use 5-7 core methods (upper, lower, split, join, replace, find, strip) to transform and search text
  • Lesson 3: F-String Formatting — Create dynamic, readable output by embedding expressions in strings

Type Conversion and Validation​

  • Lesson 4: Type Casting Fundamentals — Convert safely between int, float, str, and bool types
  • Lesson 5: Interactive String Explorer — Build a hands-on tool that demonstrates string operations and type casting with validation