Build Lists with Comprehensions

Introduction

This is the first lesson of chapter 11 in the Comprehensions, Lambdas, Closures, and I/O section of PCAP-31-03 (22% of the score, 9 of 40 items). It covers objective 5.1: list comprehensions, including the if operator and nested comprehensions. A comprehension is a compact expression that builds a new collection from an existing sequence. It replaces the common pattern "create an empty list, loop, append".