Welcome to the Treehouse Community

The Treehouse Community is a meeting place for developers, designers, and programmers of all backgrounds and skill levels to get support. Collaborate here on code errors or bugs that you need feedback on, or asking for an extra set of eyes on your latest project. Join thousands of Treehouse students and alumni in the community today. (Note: Only Treehouse students can comment or ask questions, but non-students are welcome to browse our conversations.)

Looking to learn something new?

Treehouse offers a seven day free trial for new students. Get access to thousands of hours of content and a supportive community. Start your free trial today.

iOS Swift Functions and Optionals Optionals What is an Optional?

Samar Khanna
Samar Khanna
1,757 Points

Understanding nil

So let me get this right. If i pass nil value as the condition in the if statement, the if statement recognises the condition as the BOOL value false?

Samar Khanna
Samar Khanna
1,757 Points

Also take this code: '''

func findApt (aptNumber : String) -> String? { let aptNumbers = ["101","202","303","404"] for tempAptNumber in aptNumbers { if ( tempAptNumber == aptNumber) { return aptNumber } } return nil }

if let culprit = findApt("202") { println("Apt found: (culprit)") }

let iAmGettingBugged = findApt("101") println(iAmGettingBugged) '''

Now in my console output, I am getting : "Apt found: 202" for my if statement, but "Optional("101")" for the ''' println(iAmGettingBugged) ''' code.

Why am i not getting the Optional("202") for the earlier IF statement?

Caleb Kleveter
Caleb Kleveter
Treehouse Moderator 37,862 Points

I'm not really sure, I don't know Swift yet, but it's on the list.

1 Answer

Caleb Kleveter
MOD
Caleb Kleveter
Treehouse Moderator 37,862 Points

Not quite, nil is when something is equal to nothing, look at the code below:

if text == nil
 NSLog(@"Return is nil")

text in the code above has nothing in it, ie. no content; the BOOL (Boolean) value of false means something is not true, like if I said text had a length of 100. Sorry if this doesn't make sense, it's hard to explain