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Mastering Swift 5.3

You're reading from   Mastering Swift 5.3 Upgrade your knowledge and become an expert in the latest version of the Swift programming language

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Product type Paperback
Published in Nov 2020
Publisher Packt
ISBN-13 9781800562158
Length 418 pages
Edition 6th Edition
Languages
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Author (1):
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Jon Hoffman Jon Hoffman
Author Profile Icon Jon Hoffman
Jon Hoffman
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Table of Contents (23) Chapters Close

Preface 1. Taking the First Steps with Swift 2. Swift Documentation and Installing Swift FREE CHAPTER 3. Learning about Variables, Constants, Strings, and Operators 4. Optional Types 5. Using Swift Collections 6. Control Flow 7. Functions 8. Classes, Structures, and Protocols 9. Protocols and Protocol Extensions 10. Protocol-Oriented Design 11. Generics 12. Error Handling and Availability 13. Custom Subscripting 14. Working with Closures 15. Advanced and Custom Operators 16. Concurrency and Parallelism in Swift 17. Custom Value Types 18. Memory Management 19. Swift Formatting and Style Guide 20. Adopting Design Patterns in Swift 21. Other Books You May Enjoy
22. Index

Adding external parameter names

In the preceding examples in this section, we defined the parameters' names and value types in the same way we would define parameters in C code. In Swift, we are not limited to this syntax as we can also use external parameter names.

External parameter names are used to indicate the purpose of each parameter when we call a function. An external parameter name for each parameter needs to be defined in conjunction with its local parameter name. The external parameter name is added before the local parameter name in the function definition. The external and local parameter names are separated by a space.

Let's look at how to use external parameter names. But before we do, let's review how we have previously defined functions. In the following two examples, we will define a function without external parameter names, and then redefine it with external parameter names:

func winPercentage(team: String, wins: Int, loses...
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