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iOS Object-Oriented Swift Properties Optional Property

Posted by GIUSEPPE GRAMMATICO
GIUSEPPE GRAMMATICO
9,255 Points

How to check optional is nil?

Referring to Optional Property i tried to print a comment when the optional parameter is nil.

my code is:

toy.batteries -------> value nil (i haven't save any value)

if toy.batteries != nil{ println("it's not nil") }else{ println("NIL!!!") }

I expect to print the else condition, but it doesn't. Could someone explain me why and how to get the result?

thanks (ps sorry for english)

2 Answers

David Quach
David Quach
1,479 Points

Try 

if let value = toy.batteries {
  print("Not nil")
} else {
  print("Nil")
}

The reason for this is because the property "batteries" would be an optional. To unwrap an optional you do the if let to unwrap.

GIUSEPPE GRAMMATICO
GIUSEPPE GRAMMATICO
9,255 Points
GIUSEPPE GRAMMATICO
GIUSEPPE GRAMMATICO
9,255 Points

Thanks David! I'm still programming basing my code on other kind of languages (php & actionscript ) and sometimes it's difficult to let go what you have apply for many years.

now it's clear best way to do it. :)