Join Scott Gardner for an in-depth discussion in this video Extend concrete types, part of Swift 3 Essential Training: Beyond the Basics.
- [Narrator] Extensions enable you to add new functionality…to existing types, including any types…in the Swift standard library,…or in third party APIs.…This allows you to customize these types…to best meet your needs.…I'm starting out with a string constant…and have accessed its character's count…to get the length of the string.…Wouldn't it be nice if I could just access…a length property instead?…I'll write an extension on string to do exactly that.…To define an extension, write the extension keyword…followed by the name of the type you want to extend…and then curly braces to enclose its body.…
I'll add a length calculated property to string…that simply returns characters dot count.…Self is implied here.…I could have written self dot characters dot count,…but it's not necessary.…Now I can use length on any string instance.…Extensions can be used to add computed properties,…but not stored properties,…and extensions can be used to add new initializers,…methods, and subscripts, and even nested types.…
A type can have multiple extensions defined on it.…
- Adding source files, resources, links, and literals
- Adding pages to a playground
- Using overflow operators and bitwise operators
- Using ranges with strings
- Creating complex sequences
- Chaining higher-order functions
- Defining lazy properties
- Using failable initializers
- Mutating methods
- Working with singletons
- Nesting function types
- Creating error types and recursive enumerations
- Extending concrete types
- Referencing selectors and key paths
- Working with protocol-oriented programming
- Defining class-only protocols and optional protocols
- Using option sets, type checking, and casting operators
Skill Level Intermediate
Core Data for iOS and macOS Enterprise Developerswith Jon Bott1h 46m Intermediate
Distributing Your iOS App for Testing with TestFlightwith Ron Buencamino35m 10s Intermediate
iOS App Development: Test-Driven Developmentwith Harrison Ferrone2h 14m Intermediate
3. Strings and Characters
4. Sequences and Collections
5. Control Flow
6. Value and Reference Types
9. Access Control
Understand access control3m 47s
Next steps1m 2s
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