Welcome to the Treehouse Community

Want to collaborate on code errors? Have bugs you need feedback on? Looking for an extra set of eyes on your latest project? Get support with fellow developers, designers, and programmers of all backgrounds and skill levels here with the Treehouse Community! While you're at it, check out some resources Treehouse students have shared here.

Looking to learn something new?

Treehouse offers a seven day free trial for new students. Get access to thousands of hours of content and join thousands of Treehouse students and alumni in the community today.

Start your free trial

iOS Swift 2.0 Functions Function Parameters Named Parameters

Manish Giri
Manish Giri
16,266 Points
Posted by Manish Giri
Manish Giri
16,266 Points

Error on omitting the local parameter name for first argument

While watching this lecture, I wrote this code - 

func concatenateStrings(a: String, b: String) -> String {
    return a + b
}

concatenateStrings("Hello", b: "Worlds")

But I got an error - 

Missing argument label 'a:' in call

Why is this so? My Xcode is ver 8.0, which (I think) uses Swift 3. Has the rule of omitting local parameter name for first argument changed?

1 Answer

David Lin
David Lin
35,864 Points
David Lin
David Lin
35,864 Points

Yes, Swift 3 requires explicitly labelling all parameters in function calls, including the first.