Part 4: Collections & Generics

Work with Kotlin’s collections and write reusable, type-safe code.

What You’ll Learn

• Arrays and the core collections: List, Set, Map
• Read-only vs mutable collections
• Collection operations: map, filter, fold, groupBy
• Sequences and lazy evaluation
• Generics, constraints, variance (in/out), and reified

Chapters

Chapter	Description
Collections	Arrays, lists, sets, maps; read-only vs mutable
Collection Operations	Transform, filter, aggregate, group
Sequences	Lazy vs eager evaluation
Generics	Generic functions/classes, constraints
Variance & Reified Types	in/out, star projection, reified

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Table of contents

• Collections
• Collection Operations
• Sequences
• Generics
• Variance & Reified Types