Introduction

In this chapter, we’ll further our understanding of Booleans and Boolean expressions, learn about branching and flow control, comparisons and conditions, and some convenient string methods.

Learning objectives

• You will learn more about Booleans, how to construct a truth table, and how to combine Booleans using the connectives and and or.
• You will learn how to write if, if/else, if/elif, and if/elif/else statements in Python, which allow program execution to follow different branches based on certain conditions.
• You will learn how to test for identity with is, and the difference between equivalence and identity.
• You will learn how to represent decisions using and decision trees.
• You will learn a little about input validation.
• You will learn how to use convenient string methods such as .upper(), .lower(), and .capitalize().

Terms and string methods introduced

• Boolean expression
• branching
• comparison operator
• conditional
• De Morgan’s Laws
• decision tree
• equivalence
• identity
• if, elif, and else
• is
• lexicographic order
• string methods .upper(), .lower(), and .capitalize()
• truth value
• truthiness and falsiness

Copyright © 2023–2025 Clayton Cafiero

No generative AI was used in producing this material. This was written the old-fashioned way.