FREE: Read a new Swift article every day – click here! >>

< Previous: Parameter labels   Next: Default parameters >

Omitting parameter labels

You might have noticed that we don’t actually send any parameter names when we call print() – we say print("Hello") rather than print(message: "Hello").

You can get this same behavior in your own functions by using an underscore, _, for your external parameter name, like this:

func greet(_ person: String) {
    print("Hello, \(person)!")
}

You can now call greet() without having to use the person parameter name:

greet("Taylor")

This can make some code more natural to read, but generally it’s better to give your parameters external names to avoid confusion. For example, if I say setAlarm(5) it’s hard to tell what that means – does it set an alarm for five o’clock, set an alarm for five hours from now, or activate pre-configured alarm number 5?

Test your Swift today

Think you know Swift? My book Swift Coding Challenges will put your Swift skills to the test – it's perfect for job interviews and more!

< Previous: Parameter labels   Next: Default parameters >
MASTER SWIFT NOW
Buy Testing Swift Buy Practical iOS 12 Buy Pro Swift Buy Swift Design Patterns Buy Swift Coding Challenges Buy Server-Side Swift (Vapor Edition) Buy Server-Side Swift (Kitura Edition) Buy Hacking with macOS Buy Advanced iOS Volume One Buy Advanced iOS Volume Two Buy Hacking with watchOS Buy Hacking with tvOS Buy Hacking with Swift Buy Dive Into SpriteKit Buy Swift in Sixty Seconds Buy Objective-C for Swift Developers Buy Beyond Code

Was this page useful? Let me know!

Average rating: 5.0/5

Click here to visit the Hacking with Swift store >>