#### Overview of this book

Data structures and algorithms are more than just theoretical concepts. They help you become familiar with computational methods for solving problems and writing logical code. Equipped with this knowledge, you can write efficient programs that run faster and use less memory. Hands-On Data Structures and Algorithms with Kotlin book starts with the basics of algorithms and data structures, helping you get to grips with the fundamentals and measure complexity. You'll then move on to exploring the basics of functional programming while getting used to thinking recursively. Packed with plenty of examples along the way, this book will help you grasp each concept easily. In addition to this, you'll get a clear understanding of how the data structures in Kotlin's collection framework work internally. By the end of this book, you will be able to apply the theory of data structures and algorithms to work out real-world problems.
Preface
Free Chapter
Section 1: Getting Started with Data Structures
A Walk Through - Data Structures and Algorithms
Arrays - First Step to Grouping Data
Section 2: Efficient Grouping of Data with Various Data Structures
Understanding Stacks and Queues
Maps - Working with Key-Value Pairs
Section 3: Algorithms and Efficiency
Deep-Dive into Searching Algorithms
Understanding Sorting Algorithms
Section 4: Modern and Advanced Data Structures
Collections and Data Operations in Kotlin
Introduction to Functional Programming
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Assessments

# Lambda and higher-order functions

In programming, a lambda, or lambda expression, generally refers to anonymous functions (functions without names or declarations). In Kotlin, a lambda expression starts with { and ends with }. It is called the anonymous function/lambda expression, since it doesn't contain a formal function declaration/name, but, rather, uses something more like a variable, containing an expression for a computation. Note that every lambda is a function, but every function might not be a lambda.

Lambda is strictly a language feature that isn't supported by all languages; for instance, Java didn't have support for lambda expressions till Java 8 came out, and till then, it only supported anonymous objects (instances of classes) for lambda, and not anonymous functions; in other words, you first had to create an interface, and only then could you pass...